IT
THE LIBRARY
OF
THE UNIVERSITY
OF CALIFORNIA
LOS ANGELES
THE OPHTHALMOSCOPE
AND
HOW TO USE IT
THORINGTON
BY THE SAME AUTHOR
Refraction and How to Refract
Third Edition. With 215 Illustrations, many of
which are from original drawings, seven being colored.
Cloth, net, $J.50.
From. The New York Medical Record:
"Can be recommended not only to beginners in the study
of ophthalmology, but to those practitioners and students as
well whose limited knowledge of mathematics precludes the
study of Helmholtz or Donders. ' '
Retinoscopy (The Shadow Test)
In the Determination of Refraction at One Meter
Distance with the Plane Mirror.
Fourth Edition. 51 Illustrations, a number of
which are in colors. Cloth, net, $J.OO.
THE OPHTHALMOSCOPE
AND
HOW TO USE IT
WITH COLORED ILLUSTRATIONS, DESCRIPTIONS, AND
TREATMENT OF THE PRINCIPAL DISEASES
OF THE FUNDUS
JAMES THORINGTON, A.M., M.D.
AUTHOR OF "REFRACTION AND HOW TO REFRACT" (THIRD EDITION) AND "RETINOS-
COPY" (FOURTH EDITION); PROFESSOR OF DISEASES OF THE EYE IN THE PHILA-
DELPHIA POLYCLINIC AND COLLEGE FOR GRADUATES IN MEDICINE; MEMBER
OF THE AMERICAN OPHTHALMOLOGICAL SOCIETY; FELLOW OF
THE COLLEGE OP PHYSICIANS; ETC.
73 illustrations 12 Colored plates
PHILADELPHIA
P. BLAKISTON'S SON & CO.
IOI2 WALNUT STREET
1906
COPYRIGHT, 1906, BY P. BLAKISTON'S SON & Co.
PRESS OF
THE NEW ERA PRINTKG&
LAHCASTER. PA,
PREFACE.
THIS book has been written for the student and
general practitioner who desires to obtain a work-
ing knowledge of the ophthalmoscope with the in-
terpretations of its findings, and has not the time,
ordinarily, to study a large text-book on the dis-
eases of the eye, in which the subject is too deeply
embedded for immediate comprehension.
While it is admitted by every intelligent practi-
tioner that the ophthalmoscope for the detection
of many diseases is frequently a necessity, yet to
be able to use the instrument does not mean that
the observer must be an expert ophthalmologist.
With the ophthalmoscope, the examiner may
see conditions pictured which signify disease of the
brain, spinal cord, heart, kidney, blood, blood-
vessels, etc., that he might not detect in any other
way, thus making a diagnosis with certainty and
satisfaction.
In the preparation of the manuscript and the
arrangement of these pages and chapters, the
writer has planned to be systematic and practical,
so that starting with the consideration of the oph-
thalmoscope and its optic principles as also the
optic principles and anatomy of the eye, the reader
is brought to a knowledge of the normal eye and
VI PREFACE.
has a colored sketch presented of a healthy eye
ground as a guide for comparative descriptions.
Finally the reader is given a comparison of the
normal with the pathologic, so that when he sees
a certain condition in the eye ground, he will know
at once whether the appearance indicates health,
or an anomaly or disease, and the structure or
structures involved. However, to enhance the
value of the work, the writer has selected for his
descriptions and illustrations those diseases of the
eye ground which appeal to the general practitioner
in every-day practice. The sketches in color were
made by a noted artist and under the writer's per-
sonal supervision, from individual patients in his
own practice. These sketches, made by the aid of
artificial light, should be studied under similar con-
ditions (see page in).
The subject of prognosis and treatment of the
various diseases described has not been exhausted,
but has been sufficiently touched upon to give the
reader a proper understanding of the subject with-
out making a work of this character unnecessarily
large.
120 S. EIGHTEENTH ST., PHILADELPHIA, PA.
January, 1906.
CONTENTS.
CHAPTER I.
THE OPHTHALMOSCOPE. CHOICE OF AN OPH-
THALMOSCOPE. VARIETIES. ILLUMINATION. -
THE MIRROR. MYDRIATICS. OBSERVER. PA-
TIENT. HOW TO USE THE OPHTHALMOSCOPE.
DIRECT AND INDIRECT METHODS. OBLIQUE IL-
LUMINATION i
CHAPTER II.
OPTICS. LIGHT. REFLECTION. R EFRACTION.
LENSES. HYPERMETROPIA. MYOPIA. ASTIGMA-
TISM. ESTIMATING THE REFRACTION BY THE
DIRECT AND INDIRECT METHODS AND RETINO-
SCOPY 44
CHAPTER III.
ANATOMY AND ANOMALIES OF THE EYE. 79
CHAPTER IV.
THE NORMAL EYE GROUND 108
CHAPTER V.
STRUCTURAL ALTERATIONS OR CHANGES IN THE
CORNEA, AQUEOUS HUMOR, IRIS, LENS AND
VITREOUS HUMOR WHICH ARE INDICATIVE OF
DISEASE OR INJURY 128
vii
Vlll CONTENTS.
CHAPTER VI.
VISUAL ACUITY. FIELD OF VISION. PERIMETRY. .. 140
CHAPTER VII.
RETINAL VESSELS. HEMORRHAGES. PIGMENT.
CHANGES. HYPEREMIA. ANEMIA. EMBOLISM.
THROMBOSIS 148
CHAPTER VIII.
DISEASES OF THE RETINA 176
CHAPTER IX.
DISEASES OF THE OPTIC NERVE 229
CHAPTER X.
DISEASES OF THE CHOROID. GLAUCOMA 259
INDEX 287
LIST OF ILLUSTRATIONS.
PLATES
PACE.
I. Normal Fundus To face 1 18
II. Embolism of the Central Artery " 164
III. Thrombosis of the Central Vein (So-
called Hemorrhagic Retinitis) " 172
IV. Albuminuric Retinitis " 190
V. Albuminuric Retinitis of Pregnancy.... " 198
VI. Retinitis Diabetica " 202
VII. Retinitis Pigmentosa " 208
VIII. Detachment of the Retina " 216
IX. Atrophy of the Optic Nerve (Post Pap-
illitic Atrophy) also Medullated Nerve-
fibers " 248
X. Primary Optic Atrophy " 252
XI. Retino-Choroiditis " 264
XII. Glaucoma " 278
TEXT FIGURES.
1. The Loring Ophthalmoscope 3
2. The Morton Ophthalmoscope 5
3 and 4. The DeZeng Luminous Ophthalmoscope... 7
5. The Student Lamp and Cover Chimney with Ad-
justable Bracket 10
6. Author's Iris Diaphragm Chimney n
7. Author's Schematic Eye 14
8. Correct Position for Direct Ophthalmoscopy 23
9. Correct Position for Holding the Ophthalmoscope. 24
ix
X LIST OF ILLUSTRATIONS.
PAGE.
10. Very Faulty Position of Holding the Ophthalmo-
scope 25
11. Direct Ophthalmoscopy, Outlined in Hypermetropia 28
12. Direct Ophthalmoscopy, Outlined in Myopia 29
13. Position for Indirect Ophthalmoscopy 30
14. Author's Condensing Lens 31
15. Indirect Ophthalmoscopy, Outlined 33
1 6. Oblique or Focal Illumination 38
17. Oblique or Focal Illumination and Object Magni-
fied with Condensing Lens , 39
18. Loupe 40
19. Oblique or Focal Illumination with Object Magni-
fied with Loupe 41
20. Cover Chimney with Condensing Lens Attached. . . 42
21. Illustrating Intensity of Light 45
22. Parallel Rays Refracted by a Convex Lens Form-
ing a Convergent Pencil 46
23. Parallel Rays Reflected by a Concave Mirror Form-
ing a Convergent Pencil 46
24. Illustrating a Divergent Pencil 48
25. Reflection 50
26. Reflection from a Plane Mirror 51
27. Lateral Inversion 52
28. Reflection by a Concave Mirror 54
29. Erect Image Formed by a Concave Mirror 54
30. Inverted Image Formed by a Concave Mirror 55
31. Image Formed by a Convex Mirror 56
32. Perpendicular to Plane Surfaces 58
33. Refraction 58
34. Maximum Deviation 59
35. Minimum Deviation 59
36. 37, and 38. Convex Lenses 60
39, 40, and 41. Concave Lenses 61
42. Prism Formation of a Convex Lens 62
43. Prism Formation of a Concave Lens 62
LIST OF ILLUSTRATIONS. XI
PAGE.
44. Parallel Rays Passing Through a Convex Lens. . . 63
45. Parallel Rays Passing Through a Concave Lens ... 63
46. Conjugate Foci 64
47. Negative Focus 65
48. Inverted Image Formed by a Convex Lens 65
49. Erect and Magnified Image Formed by a Convex
Lens 66
50. Image Formed by a Concave Lens 66
51 and 52. Convex and Concave Cylinder Lenses 68
53. Cylinder Axis 69
54. Parallel Rays Passing Through a Convex Cylinder. 69
55. Parallel Rays Passing Through a Concave Cylinder. 70
56. Hypermetropic Eye at Rest 70
57. Hypermetropic Eye Refracted 71
58. Emmetropia 71
59. Myopic Eye at Rest 71
60. Myopic Eye Refracted 72
61. Horizontal Section of the Right Eye 80
62. Varieties of Persistent Pupillary Membrane 101
63. Various Forms of Opacity of the Crystalline Lens. . 102
64. Head of the Optic Nerve no
65. To Determine the Position of a Fixed Opacity in
the Eye 138
66. Randall's Test Letters 140
67. Gould's Test Letters 141
68. Illiterate Card 142
69. McHardy's Perimeter 143
70. Field Charts 144
71. Form Field Showing Contraction in All Meridians. 212
72. Form Field in Partial Detachment of the Retina. . . 220
73. Depressions in Optic Disc 233
THE OPHTHALMOSCOPE
AND
HOW TO USE IT
CHAPTER I.
THE OPHTHALMOSCOPE. CHOICE OF AN OPHTHALMOSCOPE.
VARIETIES. ILLUMINATION. THE MIRROR. MYDRIATICS.
OBSERVER. PATIENT. HOW TO USE THE OPHTHALMO-
SCOPE. DIRECT AND INDIRECT METHODS. OBLIQUE
ILLUMINATION.
Ophthalmoscope. From o<0aX/xos, " eye "; and
ayoTreiv, " to observe " or literally " to view an eye."
An instrument used for studying the media and
interior of an eye.
Choice of an Ophthalmoscope. As the purpose
of an ophthalmoscope is to permit the observer to
see clearly the interior of an eye, therefore in select-
ing an ophthalmoscope it is not at all necessary to
obtain the most expensive or most complicated in-
strument, but rather to select the one which will
answer the purpose for which it is intended. The
original ophthalmoscope of Helmholtz (1851) is
a crude affair and is now a museum curiosity, as
the ophthalmoscope of the present day excels the
2 THE OPHTHALMOSCOPE.
Helmholtz instrument in every particular. There
is an infinite variety of ophthalmoscopes in the
market, but for the general student the modified
instrument of Loring appears to meet with most
favor in America, and the Morton, an excellent in-
strument, is quite popular abroad.
The Loring Ophthalmoscope (Fig. i). The
mirror of the Loring instrument is concave, with
a radius of curvature of 40 centimeters, giving
therefore a principal focus at 20 centimeters. The
sight-hole of this mirror is round and usually about
3^2 millimeters in diameter, cut through the glass.
As an improvement over such a mirror and to take
its place, the writer would recommend the mirror
used on his own ophthalmoscope which has a radius
of curvature of 15 centimeters and the sight-hole
2 millimeters in diameter, not cut through the glass,
but made by simply removing the quicksilver. The
glass left at the sight-hole gives additional reflect-
ing surface and at the same time does away with
annoying reflexes or aberrations which often oc-
cur when the glass is perforated. The small sight-
hole is an advantage also when looking through
small pupils. The mirror should be of thin glass
and the silvering of the very best quality. The
mirror can be tilted to an angle of 25 degrees, is
oblong in shape, 18 by 33 millimeters, and is se-
cured at the middle of its ends (Fig. i) by two
elevated screws to the cover on a revolving milled
wheel. This milled wheel or disk contains fifteen
THE LORING OPHTHALMOSCOPE. 3
small spheric lenses, each 6 millimeters in diameter,
set in the form of a circle near its circumference.
The series of spheric lenses of different strength
range from I D. to 8 D. and from + i D. to
FRONT BACK
FIG. i. Loring Ophthalmoscope.
+ 7 D. The central opening is left free, does not
contain a lens and is marked o. Each lens may be
turned in succession to the sight-hole by revolving
the milled wheel or disk with the end of the index
4 THE OPHTHALMOSCOPE.
finger of the hand which holds the instrument ( Fig.
10). When it is necessary to use a lens stronger
than 8 D. or -f- 7 D., there is an additional quad-
rant ("back" view, Fig. i), which can be super-
imposed and turned into place at the sight-hole;
this quadrant contains four lenses, 0.50 D. and
16 D.; also + 0.50 D. and + 16 D. With this
quadrant and the spheres in the milled wheel any
combination or strength of lens from 0.50 D. to
-24 D. and +0.50 D. to +23 D. (a series of
sixty- four) may be placed at the sight-hole, as
shown by the following table.
Plus. Mill us.
I
1 2
2 3
3 4
4 5
5 6
6 7
7 8
Bring up + 16 Bring up 16
+ i6C 8= 8 i6C + 7= 9
7=9 +6= 10
6=10 +5= ii
5 = ii +4= 12
4=12 +3= 13
3=i3 +2= 14
2=14 +1= 15
i = 15 +0= 16
0=16 i= 17
+ 1 = 17 2= 18
+ 2=18 3= 19
-(-3=19 4 = 20
+ 4 = 20 5= 21
-(-5 = 21 6= 22
+ 6 = 22 7 = 23
THE MORTON OPHTHALMOSCOPE.
Plus.
Bring up -f- 0.50
C + i =
0.50
1-50
2.50
3-50
4-50
5-50
6.50
7-50
Bring up 0.50
Minus.
8 = 24
= 0.50
: 1 = 1.50
: 2 = 2.50
: 3 = 3-50
4 = 4.50
: s = 5-50
: 6=1 6.50
: 7 = 7-50
8 = 8.50
An index immediately beneath the sight-hole of
the instrument records the strength of lens in whole
numbers that is being used. In the Morton instru-
ment each lens is projected before the sight-hole
FIG. 2. Morton Ophthalmoscope.
through an endless groove and propelled by a driv-
ing wheel and cogs at the lower end of the instru-
ment (Fig. 2). In this Loring instrument the
6 THE OPHTHALMOSCOPE.
minus lenses are numbered in red figures and the
plus lenses in white. The Morton uses the reverse
of these colors, i. e., white for the minus lenses and
red for the plus. When the 0.50 lens (plus or mi-
nus) is in position then its strength must be added
to or subtracted from the whole number at the
sight-hole. By the foregoing table it will be noted
that 8.50 and + 7.50 are the highest half-num-
bers that can be obtained or are ever necessary for
any purpose. The handle of either ophthalmoscope
is made partly of brass and partly of bone; this
latter can be unscrewed when the instrument is to
be placed in its case. In the case with the ophthal-
moscope there is a convex lens of + 16 D., which
will be described later.
The Luminous Ophthalmoscope (Figs. 3 and
4), DeZeng Patent. This instrument is the Lor-
ing ophthalmoscope just described with the addi-
tion of an electric light attachment and a mirror of
different size and shape. This mirror is plain, cir-
cular in form, 14 millimeters in diameter, with one
millimeter of its upper area cut away horizontally.
The flat top edge of the mirror is on a level with the
lower edge of the sight-hole in the ophthalmoscope ;
this mirror is placed at an angle of 43 degrees and
firmly secured to the instrument as it is never neces-
sary to tilt it. The observer in looking through the
sight-hole always looks over the mirror and never
through it. The handle of the instrument is hollow
and carries the electric wires to a small 5-volt lamp
THE LUMINOUS OPHTHALMOSCOPE.
in the handle. Between the lamp and the mirror is
placed a very strong planoconvex lens. The rays
FIG. 3. FIG. 4.
DeZeng Luminous Ophthalmoscope. Two-thirds size.
of light from the filament falling upon the convex
lens are refracted very convergently and after re-
8 THE OPHTHALMOSCOPE.
flection from the mirror converge to a point one
inch distant (Fig. 4). The luminous ophthalmo-
scope is so convenient for use in the wards of
a hospital, etc., and renders ophthalmoscopy so
much less difficult that the instrument at once com-
mends itself to every physician. This instrument
is ideal both for the direct and indirect method,
and has the following points of merit : The mirror
and light are stationary, thus giving the observer
any liberty of movement necessary without any loss
of the reflection from the mirror, the mirror never
requires any tilting, the brilliancy or intensity of the
illumination at the fundus by virtue of the light
being so close to the mirror far exceeds that of the
non-luminous instrument, and for the same reason
the size of the retinal illumination is made about
five times larger than that by the old style instru-
ment. The heat from the electric lamp is infinitesi-
mal. An electric light attachment is also made for
the Morton ophthalmoscope.
Electricity to supply the luminous ophthalmo-
scope may be furnished by a portable, storage, or
dry cell battery or by the Edison street current.
No matter what the supply may be, there should
always be a convenient rheostat attacluncnt at liand
so that the operator may know that he is not using
more current than the delicate lamp can possibly
endure.
The Thorner Ophthalmoscope is a large sta-
tionary instrument and an expensive one. It is
HOW TO USE THE OPHTHALMOSCOPE. 9
used principally for magnification and class demon-
stration and is therefore not a part of the subject
matter of this manual.
How to Use the Ophthalmoscope. While the
beginner in ophthalmoscopy may see into an eye
the first time he makes the attempt, yet proficiency
with the use of the ophthalmoscope does not come
except by long and constant practice. The pupil
of an eye in health appears to an observer as black
(the eye of an albino excepted) ; this is due to the
fact that the observer's eye does not ordinarily in-
tercept any of the rays of light which return from
the eye. Rays of light entering an eye are returned
by that eye toward their immediate source and
therefore, if an observer wishes to see into or
study the interior of an eye, he must have his own
eye in the path of the returning rays. To accom-
plish this, the observer places a mirror in front of
his eye and reflects light into the pupil of another
eye, and as the rays return from the eye under ob-
servation, to the mirror from which they came, the
observer is able to receive some of these return
rays into his own eye through a small opening
which has been previously made in the mirror.
Several important matters should receive very
careful attention from the student or beginner be-
fore he attempts to use the ophthalmoscope, and
these points will be taken up seriatim.
The Room. This should be darkened by draw-
ing the shades or closing the blinds, the darker
10
THE OPHTHALMOSCOPE.
the room the better, though it is not at all necessary
to have the walls painted black or draped in black
cloth. All lights except the one in use should, if
possible, be excluded from the dark room. If the
surgeon has a convenient room adjoining his office
and so desires, he may have it fitted up as a " dark
room " by having the walls and ceiling painted
black or draped in black felt, as just suggested.
The Light. A candle flame is almost useless
as it is not steady and moves with each current of
air. Gas is the most common and convenient illumi-
FIG. 5. Student lamp with cover chimney, on adjustable bracket.
nant, as nearly every house, even in the smallest
city, is piped for the purpose, and with rubber
tubing this may be brought to any adjustable stand.
A good quality of kerosene, in a modern lamp, may
be used if gas cannot be had. The student lamp is
good, but the flame is rather narrow. The student
lamp on a bracket is good if the cover chimney
THE LIGHT.
I I
is used ( Fig. 5 ) . To use daylight it would be nec-
essary to have a round opening i l / 2 inches in di-
ameter in the closed blind or drawn shade, and this
opening would have to be exactly placed to meet
the conveniences of the office furniture. But day-
light is an uncertain quantity and cannot be relied
upon. There is one thing in favor of daylight how-
ever, and that is we can see
the eye ground in its natural
coloring and not altered by
the yellow coloring from the
reflected gas or lamp light.
The regular i6-candle-power
electric light with its narrozv
filament is somewhat objec-
tionable, though some obser-
vers use it, preferably with a
ground glass bulb or the coiled
filament. There is no objec-
tion to the Welsbach light if
the mantle is intact. What-
ever variety of light is used it
should have the qualifications
of being steady and bright,
a white light if possible. The Argand burner is
the most generally employed and most satisfactory
when on a convenient right-angled bracket ( Fig. 5 )
which can be raised or lowered, and is capable of
lateral movement. The flame or electric light may
be exposed or covered with the iris diaphragm
FIG. 6. Author's Iris Dia-
phragm Chimney.
12 THE OPHTHALMOSCOPE.
chimney (Fig. 6). If the luminous ophthalmoscope
is used, the question of light is settled at once, as
the filament gives a point of light which is perfect.
And furthermore, the light and mirror of this in-
strument being two fixed points, the observer has
no trouble in keeping his light in position for reflec-
tion and does not have to tilt his mirror, and for
bedside work the observer can follow the eye of the
most restless patient without losing the reflection.
Reflection from the Mirror. It has already
been stated that the concave mirror on the ophthal-
moscope has a radius of curvature of 40 centi-
meters (16 inches) and this means that if the light
is placed 20 centimeters (8 inches) from the mirror,
the rays of light would be reflected parallel. This
should be borne in mind for occasionally parallel
rays are required and this is a good way to obtain
them, and if divergent rays are required the light
must be placed at six or seven inches. If the
light is just 40 centimeters from the mirror, then
the reflected rays would have a convergence of
40 centimeters, as this distance represents the cen-
ter of curvature (c.c. in Fig. 29).
To summarize:
1. To obtain parallel rays of light reflected from
the mirror, place the light 20 centimeters distant.
2. To obtain divergent rays of light reflected
from the mirror, place the light closer than 20
centimeters.
3. To obtain convergent rays of light reflected
MOVEMENT OF THE MIRROR. 13
from the mirror, place the light beyond 20 centi-
meters. The further the light is beyond 20 centi-
meters from the mirror, the greater the conver-
gence.
For most ophthalmoscopic work convergent rays
are employed, but when studying minute changes
in the retina, nerve-head, vitreous, etc., a faint
light is sometimes required, and at other times in
studying gross changes, the brightest or most in-
tense light obtainable is necessary ; the former may
be obtained by reducing the size of the flame in use,
or substituting a plane mirror. With the luminous
ophthalmoscope and a convenient rheostat a very
intense light, or one of moderate strength, may be
obtained. A concave mirror gives a more brilliant
illumination than a plane mirror, and each has its
particular advantages, as in certain instances, just
referred to; and mirrors with different radii of
curvature could be used to advantage, but too many
mirrors are an inconvenience. The Morton oph-
thalmoscope has a concave and also a plane mirror
which may be used independently. Light from the
concave mirror usually falls as a converging cone
of light, and the base of the cone is the mirror, but
when examining an eye by the direct method (Fig.
8) then only those rays around the sight-hole of
the mirror enter the patient's pupil.
Movement of the Mirror. The mirror must
always be tilted toward the light. When looking
into the eye from a short distance and before be-
THE OPHTHALMOSCOPE.
ginning a study of the fundus of the eye, it is well
to reflect the light into the eye by moving or rotat-
ing the handle of the ophthalmoscope, so that the
light passes through the different meridians, hori-
FIG. 7. The Author's Schematic Eye.
zontally, vertically and diagonally, and in this way
opacities and the character of the refraction of the
eye, may be promptly recognized. These conditions
will be referred to elsewhere in the text.
Schematic Eye (Fig. 7). Before hurrying to
MYDRIATICS. 15
look into a patient's eye, the beginner will feel
much more confident if he has acquired previous
experience, by looking into one of the many sche-
matic eyes to be found in the shops. While ad-
mitting that the schematic eye has its disadvan-
tages or imperfections and is not equal to the
human eye in all particulars, yet it has just those
qualifications which make it so essential for the
beginner with the ophthalmoscope, namely, (a) it
does not wink; (b) it does not suffer from photo-
phobia (dread of light) ; (c) it does not suffer from
lacrimation; (d) it does not get tired; (e) its retina
does not suffer from light stimulus; and, best of
all, (/) it has a dilated pupil.
Mydriatics. (Drugs which dilate the pupil.)
When using the ophthalmoscope to examine the
live eye, it is certainly an advantage to have the
pupil dilated, especially so for the novice, but this
condition is often a great inconvenience to the pa-
tient, and some patients will positively refuse to
have any " drops " used, while others will permit
the use of the drops, but find fault on account of
the resulting discomfort, and others will have a
dread of resulting impaired sight, or another
patient might have glaucoma (Chapter XI. and
Plate XII.), a disease which would preclude the
use of a drug which would crowd the iris into the
angle of the anterior chamber. Fortunately for the
beginner as well as for the expert, with the ophthal-
moscope, the disc (optic nerve head) is the princi-
l6 THE OPHTHALMOSCOPE.
pal part of the fundus usually affected by glaucoma,
and it is this part which is most easily examined
without a mydriatic. The great thing therefore
for the student is to learn to use the ophthalmoscope
on the schematic eye and when he has mastered
the technic, to then learn as soon as possible to ex-
amine the same schematic eye by adjusting to it
a small pupil made by cutting a 3^ millimeter
round opening in a card. After some considerable
practice in this way, sufficient skill will have been
obtained whereby the student will be able to tell
when looking into the human eye whether there
is any disease present, and whether this disease
precludes the use of a mydriatic or if it will
be necessary to employ a mydriatic so that the
interior of the eye may be studied more mi-
nutely. If glaucoma is not present and there
are no symptoms of glaucoma, then if necessary
for further examination, or refraction or further
study, a mydriatic may be employed. One of the
safest mydriatics, and one that has but a brief effect
and appears to have the least amount of danger at-
tached to its use, as far as the production of glau-
coma is concerned, is a fresh 4 per cent, solution
of cocain ; one or two drops of this solution should
be placed on the upper part of the eyeball as the
upper lid is held upwards and the patient looks
downwards; the solution passing freely over the
cornea and its margins is soon absorbed. Cocain
used in this way will give a maximum dilation of
MYDRIATICS. 17
the pupil in about twenty minutes. This dilation
will last for a few hours ordinarily, but as cocain
has very little, if any, effect on the accommodation,
the patient will not object to the temporary photo-
phobia, which passes away as soon as the pupil
regains its normal size. After the examination has
been completed under cocain mydriasis, the writer
urges and advises counteracting the mydriatic ef-
fect by instilling a weak solution of eserin, one
drop of a l / grain to the ounce of distilled water.
This is simply a matter of extreme prudence and
can do no harm, but might possibly do an immense
amount of good. A 2 per cent, solution of euthala-
min may be used in preference to cocain. If there
is any disease of the interior of the eye that is
injuring the sight or may injure the sight later
on, then it is certainly the part of caution on the
part of the surgeon to so inform the patient before
using a mydriatic, so that if the patient's vision
becomes impaired later on, the surgeon may not be
accused of any wrong doing from having used
drops. In competent hands there is very little if
any danger from the use of mydriatics. 1 One drop
1 Hughlings-Jackson, Lectures on Optic Neuritis, Med. Times and
Gazelle, September 16, 1871 : " If we use the ophthalmoscope, or if
we use atropin, or if we apply a blister to the head, or adopt any new
kind of treatment, the patient may blame us for his blindness, if he
saw well before such procedures. A patient who reads the smallest
print and supposes his sight to be good, may have double optic neu-
ritis. The use of atropin affects his sight for near objects gravely,
and if, from advance of the neuritic process, what I may call ' retinal
sight,' fails before the effect of the atropin has passed off, he very
1 8 THE OPHTHALMOSCOPE.
of a solution of homatropin hydrobromate (one
grain to the ounce of water) will answer the same
purpose as the cocain solution, but the effect is more
lasting and has some action on the accommodation.
The Observer. If the observer has any de-
cided refractive error, he should wear his correct-
ing glasses, and at the same time should learn as
soon as possible to relax his accommodation when
using the ophthalmoscope, so that when he looks
at the eye ground and has to turn a lens in front
of the sight-hole to get a clear picture, he will
know at once that the lens so used is an approxi-
mate estimate of the refraction of the eye being
examined. As a general rule, the beginner's
accommodation makes him apparently myopic or
near-sighted, as he strains his eye in his efforts to
see the nerve or fundus about an inch or two dis-
tant, but he need not worry or make himself un-
happy about this, but go ahead and use any lens
that will enable him to see the nerve and eye-ground
or whatever he wishes-, and later on he will learn
to relax his accommodation and then use a weaker
naturally blames us for the subsequent permanent affection of his
sight. A patient, when asked how long his sight had been bad, re-
plied : ' Only since the drops had been put in.' We must, then, when
we discover neuritis, sight being good, tell the patient that his eyes
are not really good, and that we are anxious about his sight.
Whether we give this warning or not, we shall be blamed by an unin-
telligent patient for ' tampering with his eyes.' We must, however,
act for our patient's good, regardless of selfish considerations. In
very many cases we can see enough for diagnostic purposes without
using atropin."
THE OBSERVER. 19
lens at the sight-hole. However, he should not de-
lay in his efforts to learn to relax his accommoda-
tion and the ability to do so, he will find one of the
most difficult things in the whole of ophthalmo-
scopy, and it will take him some time to accomplish
it. There are three reasons for the beginner to
wear any necessary correcting glasses and to learn
to relax his accommodation, i. e., (a) that he may
see clearly and with the least amount of effort; his
eyes, in other words, should be in an emmetropic
condition (see Emmetropia, p. 71 ) ; (b) that he may
not develop headaches and eye strain, and (c) that
he may not count his own refractive error as be-
longing to, or as a part of the patient's eye con-
dition, which he would be very likely to do, if
he did not wear his glasses or make due allow-
ance for his own refractive error. A good way
for the observer to learn to relax his accommo-
dation, is to place a pair of plus three diopter
spheres over his correcting glasses and practice
reading ordinary sized print, such as is used in
this book, and to read it at thirteen inches distant,
which is the principal focal distance of the spheric
lenses used. Another way to relax the accommo-
dation when looking into the eye, is to imagine
that the eye ground or disc is very distant, in
place of being an inch or so away. Another very
good way to accomplish the same thing, is to learn
at once to keep both eyes wide open. Too many
students will insist upon squinting one eye shut or
2O THE OPHTHALMOSCOPE.
holding it shut while using the other eye, and the
result is, they will accommodate several diopters
more than there is any real necessity for doing.
This habit of squinting one eye is a very bad habit
indeed and one which many students have had
great difficulty to overcome. Another and excel-
lent way to learn to relax the accommodation, and
one which others have appreciated, is to practice
on the schematic eye. The schematic eye has an
index which records emmetropia, hypermetropia,
and myopia, so the beginner may set the eye at any
number of diopters of hypermetropia or myopia and
then taking the ophthalmoscope in hand, he must
learn to see the eye ground of the schematic eye
with the lens at the sight-hole in the ophthalmoscope
which corresponds to the amount of the refractive
error indicated by the index. For instance, if the
schematic eye is set for 3 D. of hypermetropia, then
the + 3 D. must be turned into the sight-hole of
the ophthalmoscope, when the observer views the
eye ground, and he must learn to see the details
of the fundus with this + 3 D. and no other lens.
The approximate estimation of the various refrac-
tive errors, will become comparatively easy as soon
as the student learns to relax his accommodation.
This will be referred to later (Chapter II.).
Position of the Observer. The observer should
be comfortably seated at the side of the patient cor-
responding to the eye he is to examine, if examin-
ing the right eye, the observer should be on the
POSITION OF LIGHT. 21
patient's right; if the left eye, then on the pa-
tient's left side. When examining the right eye
the ophthalmoscope is held in the right hand
and before the right eye (Fig. 8) ; and in the left
hand and before the left eye when examining the
left eye. The examiner's eye should be a little
above or higher than the patient's eye. The ex-
aminer's head should be tilted slightly in the di-
rection of his shoulder corresponding to the eye
he is using (Fig. 9).
To meet all the requirements for the comfort of
the observer, he will do well to have a stool with
revolving top or seat, that he may adjust his posi-
tion promptly and to suit the individual patient.
Position of Light. If the mirror on the oph-
thalmoscope is of 40 centimeter radius, then to
begin the examination, the light should be about
this distance to one side and back of the patient
and on a level with the patient's eye ; in other words,
the light should be placed at an angle of 45 degrees
with the plane of the patient's face, so as to illumi-
nate the outer half of the eye-lashes of the eye to be
examined, and it may be well also to have the tip
of the patient's nose illuminated at the same time
(Fig. 8). The beginner should appreciate these
points of position, for if the light cannot take
this direction from the flame, and the flame should
be back of the patient's ear, then there cannot be
any reflection from the mirror when close in front
of the patient's eye, as the temple and ear would
22 THE OPHTHALMOSCOPE.
cut off the light from the mirror. Many students
when learning to use the ophthalmoscope, neglect
this position of the light, and when they get close
to the eye to examine it, lose the reflection and
wonder why they lose it.
Position of Patient. The patient should be
seated in a comfortable chair without arms (Fig.
8), and be instructed to look straight ahead into
vacancy, or across the room at some large object
about on a level with his eyes; in this way his ac-
commodation will relax considerably and his pupil
will be larger. He is also instructed to change the
direction of his vision only when told to do so.
Under no circumstances should the patient be al-
lowed to look at a light or into the mirror, as the
light stimulus falling upon the macula, will cause
the pupil to contract. If the patient is a child and
will not concentrate the vision as just directed,
then it will be necessary to have some one stand
back of the observer, and, by snapping the fingers
or clapping the hands, or dangling a bunch of keys
or a watch, attract the child's attention, and thus
keep it from looking into the mirror. If the pa-
tient has a squint, it will be necessary when ex-
amining the squinting eye to have the fixing eye
covered with a folded handkerchief, or held gently
shut with the finger, or shielded with a card, and
in this way the squinting eye will ordinarily turn
straight and the observer will have an opportunity
to examine it. With children it may be necessary
POSITION OF PATIENT.
24 THE OPHTHALMOSCOPE.
to employ the indirect method (Fig. 13). The
patient and observer should each keep both eyes
open. The one exception to this, is when the pa-
tient has a squint as just stated.
How to Hold the Ophthalmoscope. The ob-
server should hold the ophthalmoscope as vertical
as possible and have the sight-hole directly in front
FIG. 9. Correct position of holding the ophthalmoscope. Top of in-
strument resting in the hollow of the brow and the side resting on or
touching the side of the nose. Ophthalmoscope is held vertically before
the right eye and the observer's head is inclined slightly toward the
right shoulder with the arm close to the side. Without changing the
position of the instrument the observer can easily turn the milled wheel
with the tip of his index finger, as shown in Fig. 10.
HOW TO HOLD THE OPHTHALMOSCOPE. 25
of his pupil and close to his eye. The upper mar-
gin of the ophthalmoscope resting in the hollow
of the brow, and the side of the instrument against
the side of the nose (Fig. 9). The observer's arm
should be at his side and not form an angle with
FIG. 10. Very faulty position of holding the ophthalmoscope for direct
examination. The arm and hand and handle of the ophthalmoscope are
turned outward. The index finger, however, is in the correct position
for turning the milled wheel, as referred to in Fig. 9.
his body. If the arm of the hand holding the
ophthalmoscope is bent outward (Fig. 10), and
not kept vertical, then when the observer gets
close to the patient's eye his hand is liable to, and
4
26 THE OPHTHALMOSCOPE.
very likely will, strike the patient's nose, an evi-
dent indication of want of skill or experience.
How to Use the Ophthalmoscope. There are
two ways, or methods, of using the ophthalmo-
scope; one is called the direct, and the other the
indirect method. The direct method (Fig. 8)
gives an erect, virtual, and enlarged image of the
interior of the eye, while the indirect method (Fig.
13) gives or produces an inverted and real image,
but much less magnified than the direct. The
principle of the direct method is similar to a sim-
ple microscope, and the indirect to a compound
microscope.
The Direct Method. Executing the several
details as just given as regards the room, the
light, etc., the observer begins his examination
at a distance of 25 or 30 centimeters from the
eye, never closer, and at this distance he re-
flects the light into the eye and observes a " red
glare " which occupies the previously black pupil.
This red glare is called the " reflex " and is due
to the reflection from the choroidal (vascular)
coat of the eye. The color of this reflex varies,
(a) with the size of the pupil, (b) transparency
of the media (cornea, aqueous, lens and vitreous),
(c) the refraction, (d) the amount of pigment in
the eye ground, and (e) with detachment of the
retina, growths, etc. Having obtained the reflex,
it will be well for the observer to practice keeping
the light on the pupil, by changing his distance
SIZE OF IMAGE. 2J
while still holding the ophthalmoscope in front of
his eye, approaching the eye as close as an inch
or two; this must be done slowly and not with a
rush. The direct method, therefore, is so called
from the fact that the observer looks directly into
the eye. A detailed description of the eye ground
is given in Chapter IV.
Size of the Image of the Eye Ground. In this
direct method of looking into the eye, the optic
nerve head, retinal vessels, etc., are all enlarged
on account of the strong refracting or magnify-
ing power of the cornea and lens; the result is,
that on account of the enlargement the eye ground
seems to be at some distance behind the eye (Figs,
ii and 12). The nerve head in an emmetropic
eye, as seen with the ophthalmoscope, appears
about 25 millimeters in diameter, and about 250
millimeters distant. The actual distance of this
nerve head from the nodal point in the lens, is
about 15 millimeters, therefore the actual size of
the nerve head must be 15/250 of 25, or 3/2, or
1.5 millimeters; then 15, the nodal distance, is to
the supposed distance, 250 millimeters, as the ac-
tual size, 1.5 is to the magnified size, 25; which is
16.6, the magnification; or, to put it mathematically
15:250:: 1.5:25=16.6.
In other words, when the emmetropic nerve head
is observed, it appears about 16.6 times larger than
it actually is. The disc of a hypermetropic eye
28
THE OPHTHALMOSCOPE.
appears smaller than that of an emmetropic eye,
and the disc of a myopic eye appears larger. Just
as the nerve head appears magnified, so the ves-
sels of the eye ground appear correspondingly
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enlarged and this becomes extremely interesting,
when it is known that some of the small vessels
of the retina are less than 1/700 of an inch in
diameter, and the largest vessels less than i/ioo
THE INDIRECT METHOD.
of an inch. The capillaries of the retina in health
are invisible with the ophthalmoscope.
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The Indirect Method (Fig. 13). To examine
the eye ground by the indirect method, the ob-
server requires a convex lens of about 13 diopters
in addition to his ophthalmoscope. The convex
THE OPHTHALMOSCOPE.
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THE INDIRECT METHOD. 31
lens which comes in the case with the ophthalmo-
scope (+ 16 D.) is usually too strong and of too
small aperture, and on this account the writer
prefers his condensing lens, as pictured in Fig.
FIG. 14. Author's Condensing Lens. Two-thirds size.
14 (reduced one-third in size). This lens has a
metal rim which assists in preserving the lens
from breakage and a convenient handle which
makes it much easier to manipulate. To make
the indirect examination, the light (as bright as
possible) may be placed, (i) as in the direct
method, and the observer may keep his position
at the side of the patient corresponding to the
eye to be examined, or (2) the light may be placed
above the patient's head, or (3) on a level with
the top of the patient's head. It is customary
with many observers to take a seat in front of
the patient, but this is not at all necessary, and in
fact it is sometimes quite unnecessary and rather
to be avoided. Whether the observer sits at one
side or in front of the patient, his eye should be
32 THE OPHTHALMOSCOPE.
about 16 or 20 inches from the eye under obser-
vation, when beginning the examination. At this
distance and the light in position, with the patient's
right eye to be examined, the observer holds the con-
densing lens with his thumb and index finger of
his left hand, and rests his little and ring fingers
on the patient's right temple or forehead, so that
the condensing lens is about two or three inches
from the eye. Then, with the ophthalmoscope
held in the usual position before his right eye, the
observer reflects the light through the condens-
ing lens into the eye and very slowly approaches
or moves back from the eye until he recognizes
a retinal vessel or the optic disc; he must remem-
ber, however, that he is not looking into the eye,
but is viewing an aerial image of the eye ground
formed in the air between the condensing lens and
the ophthalmoscope. This image, besides being
aerial, is inverted, and has undergone lateral in-
version, so that the right side of the eye ground
becomes the left side of the image, and the left
side of the eye ground becomes the right side of
the image, the upper portion of the eye ground
becomes the lower portion of the image, the lower
portion of the eye ground becomes the upper por-
tion of the image (Fig. 15). While making this
examination the patient is directed to look straight
ahead, then to gradually turn the eye in various
directions to suit the observer's wishes. In this
way, various portions of the eye ground are care-
THE INDIRECT METHOD.
33
fully inspected or studied. The disc is generally
the principal part of the eye ground or part of
the image first looked for, and to bring it into
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view at once the patient is told to look a little to
the observer's right when examining the right
eye, and to the observer's left when examining
the left eye. It has already been mentioned that
34 THE OPHTHALMOSCOPE.
the patient should be told to rotate his eye in dif-
ferent directions as the observer tells him, but
this is not always satisfactory, as many patients
will turn the eye too far, and therefore it may be
just as well to have a nervous patient fix his gaze in
one direction and let the observer learn to move the
lens, slowly upward, downward, inward, outward
and diagonally. The observer must also learn to
move the lens closer to the eye or to bring it away
from the eye, as necessary, and in this way get the
most distinct image. It may be necessary at times to
rotate the lens on its axis. The stronger the con-
densing lens employed, the larger the view of the
fundus, but the details will be smaller; the weaker
the condensing lens, the smaller will be the view
of the fundus, but with larger, magnified individ-
ual points in the image- To relieve the observer's
accommodation and to magnify the aerial image
la plus four lens is usually placed at the sight-hole
of the ophthalmoscope. This plus four lens, cor-
responds to the eye piece of the microscope; when
examining eyes that are highly myopic it may be
omitted. Practicing the indirect method, the ob-
server sees a larger part of the eye ground at one
time than by the direct method, but it is not mag-
nified to the same extent as in the direct method.
It is a method, however, that is easier and more
convenient in many ways than the direct, and yet
many ophthalmologists neglect to use it. It is a
method too that does not necessarily require a
THE INDIRECT METHOD. 35
dilated pupil. It is a method that is occasionally
of great convenience in the clinic, when objection-
able (unclean) patients come for examination, and
the physician desires to keep at a good distance.
Both the direct and indirect methods should be
practiced and they are comparatively easy when
the patient has large pupils, but with very small
pupils a detailed and satisfactory examination,
while it may be obtained, is often difficult. When
practicing the indirect method, the observer should
keep both eyes open as with the direct method.
And he may use his right eye when looking at the
patient's right eye, and his left when looking at
the patient's left, or he may use his right eye in
each instance. This is purely a matter of conveni-
ence. While viewing the disc with the indirect
method, some approximation of the refraction may
be obtained when the condensing lens is gradu-
ally withdrawn from the eye.
1. When the image of the disc appears to in-
crease in size, the refraction is myopic; and if
2. The image of the disc diminishes in size, the
refraction is hypermetropic ; and if
3. The image of the disc does not change in
size, it is emmetropic.
4. For astigmatism. If the image of the disc,
which is the part usually selected for making this
estimate, appears of uniform size in one meridian,
whether the condensing lens is brought closer to
or removed from the eye, then that meridian is
36 THE OPHTHALMOSCOPE.
emmetropic, but if the meridian grows smaller as
the lens is withdrawn from the eye, then that me-
ridian is hypermetropic, if it grew larger then it
would be myopic. Withdrawing the condensing
lens and all meridians appear to grow smaller but
one more so than the other then the condition is
one of compound hypermetropia. If all meridians
grew larger but one more so than another then
the condition would be one of compound myopic
astigmatism.
The image growing smaller in one meridian and
larger in the other, as the condensing lens is with-
drawn from the eye, would signify mixed astig-
matism.
To study the presence of an elevation of the
disc or the elevation of a growth or detachment,
or to study the depth of a cupping of the disc, then
after getting the aerial image and moving the ob-
jective lens from side to side and up and down,
the near points of the image will appear to move
faster than the points beyond; this is known as
the parallactic movement.
The Size of the Image of the Eye Ground.
This depends upon the refraction of the eye and
the distance of the convex lens from the eye under
examination. In the standard (emmetropic) eye
the size of the image is always the same, no mat-
ter how far away from the eye the convex lens is
held. To estimate the size of the image, as seen
in the standard eye, all that is necessary to know
OBLIQUE ILLUMINATION. 37
is the principal focus of the condensing lens em-
ployed: if + 13 D., then the image is formed at
about 75 millimeters (three inches), and remem-
bering that the nerve head in the standard eye is
15 millimeters back from the nodal point, the size
of the image will be to the size of the nerve head,
(if that is what is looked at in the image) as their
respective distances from the nodal point and con-
densing lens, or as 15 is to 75, which equalsj^ the
magnification. Comparing the two methods of ex-
amination, the direct and the indirect, the former,
while it gives a smaller view of the fundus, yet it
is greatly magnified, sixteen times as compared to
five by the indirect, hence for the examination of
a minute point, such as a hemorrhage or growth
or foreign substance, small detachment, etc., the
direct method, is far superior to the indirect. The
direct method gives an erect image and the ob-
server recognizes at once each point of the eye
ground in its correct anatomic position. With the
direct method the observer can turn a lens into
the sight-hole of the ophthalmoscope, which ap-
proximately corrects the refractive error of the
eye under observation.
Oblique Illumination, or Focal Illumination.
The cornea, aqueous humor, lens and anterior por-
tion of the vitreous body, should have careful con-
sideration, for a clear view of the eye ground
depends upon the transparency of these media.
This is a most important part of the examination
THE OPHTHALMOSCOPE.
O15LIOUK ILLUMINATION.
39
H <L> H
*- <n
'"
'S -
4O THE OPHTHALMOSCOPE.
and the cautious physician will not omit this part
of the study, especially if a clear view of the eye
ground, cannot be obtained with the ophthalmo-
scope. This method of examination is called the
oblique or focal, because the light is usually con-
densed from the side by means of a lens and made
to fall successively upon and into the cornea, aque-
ous humor, lens and anterior portion of the vitre-
ous humor. The source of light or illumination,
lamp or gas flame, is placed one or two feet from
the head of the patient and to the side correspond-
ing to the eye to be examined, and at the same
time a little to the front and above the level of
the eye (Fig. 16). A con-
vex lens of short focus,
+ 13 D. or + 16 D., is held
in the hand of the surgeon,
between the light and the
eye under examination, and
about three inches from the
eye, so that the converging
FIG. 1 8. Loupe. J
pencil from the lens is
thrown upon and into the eye. As the lens is
moved from side to side and up and down and
diagonally, each part of the cornea, aqueous and
iris may be carefully inspected. Or, in place of
moving the condensing lens, it may be held still,
and the patient told to rotate the eye in certain
given directions. When a minute point, is to
be carefully examined by itself, then the con-
OBLIQUE ILLUMINATION.
U to
J5 C
H c
2 i 1
o rt ~
e. ^
42 THE OPHTHALMOSCOPE.
densing lens, must be moved closer to the eye or
away from it until the apex of the cone of con-
verging rays will fall directly upon the point se-
lected. To study the anterior layers of the vitre-
ous and the peripheral portions of the lens of the
eye, it is often necessary to dilate the pupil, and
the light must now be placed a little more to the
FIG. 20. Cover chimney with condensing lens.
front of the eye under examination (Fig. 19).
The patient's head should also be tilted a little
backwards and the observer must get a little to
one side, so as not to intercept the rays from the
light. If the observer wishes to magnify the part
under examination, he may do so by holding an-
other lens of the same focus, or of stronger power,
between the thumb and index finger of his other
hand, and gaze at the spot through this second
lens (Fig. 17). Another convenient way to mag-
nify the part looked at, or to examine for foreign
substances (cinders, etc.) is to use a " loupe." This
OBLIQUE ILLUMINATION. 43
is pictured in Figs. 18 and 19. A very good way to
condense the light onto the cornea when the sur-
geon wishes to use his hands for another purpose,
for instance when removing a foreign substance,
is to have a strong lens from the trial case placed
in the notch in front of the iris diaphragm, on the
cover chimney, or to use a cover chimney with tele-
scopic attachment as shown in Fig. 20.
CHAPTER II.
OPTICS. LIGHT. REFLECTION. REFRACTION. LENSES.
HYPERMETROPIA. MYOPIA. ASTIGMATISM. ESTIMAT-
ING THE REFRACTION BY THE DIRECT AND INDIRECT
METHODS AND RETINOSCOPY.
To assist the beginner in ophthalmoscopy, who
should have a general knowledge of the optic prin-
ciples on which the ophthalmoscope is constructed,
and also the optic principles of the eye he is to ex-
amine, the writer has prepared this chapter, bor-
rowing freely from his work on " Refraction and
How to Refract."
Light. Light is that form of energy which
acting upon the organ of sight renders visible the
object from which it proceeds. This energy is prop-
agated in waves in all directions from a luminous
body and with a velocity in a vacuum of 186,000
miles in a second of time. In the study of a lumi-
nous substance such as a candle, lamp or gas flame,
the substance itself must not be considered as a sin-
gle source of radiation, but as a collection of innu-
merable points of light, from every one of which
waves or rays proceed in all directions and cross one
another as they diverge from their respective points.
In other words, all rays of light proceeding from a
point are divergent.
Intensity of Light. The intensity of light di-
44
RAYS. 45
minishes as the square of the distance ; for example,
if an object is twice as far from a luminous body
as another of the same size, it will receive one-
fourth as much light as the latter. Fig. 21 shows
FIG. 21.
rays of light illuminating a card about one inch and
a half away from the candle flame, and the second
card just the same size, at twice this distance re-
ceives only one-fourth the amount of illumination.
If the second card had been four times as far away
it would have received only one-sixteenth as much
illumination.
Ray. Ray from radius, meaning a straight
line, is a word used in optics in preference to
wave, and means the smallest subdivision of light.
Rays of light are considered as incident, emergent,
reflected, refracted, divergent, parallel and con-
vergent.
Incident Rays. Rays of light are said to be
incident when they strike or fall upon the surface
of an object. Rays of light from the candle in
Fig. 21 falling upon the card are incident rays.
These rays are also spoken of as divergent rays.
Emergent Rays. Rays of light are emergent
4 6
THE OPHTHALMOSCOPE.
when they have traversed or passed through a
transparent substance. This is demonstrated or
shown by the incident or parallel rays in Fig. 22,
FIG. 22.
which have undergone refraction by the plano-
convex lens, and are now emergent; these latter
rays in this instance are also spoken of as con-
vergent.
Reflected Rays. Rays of light are reflected
when they rebound from a polished surface.
This is shown in Fig. 23. See Laws of Reflection.
FIG. 23.
Refracted Rays. Rays are refracted when they
are deviated from their course in passing through
RAYS. 47
any transparent substance. This is shown in
Fig. 22; as the rays emerge from the lens they
are deviated from their course.
Divergent Rays. Rays of light proceed diver-
gently from any luminous substance, but in the
study of refraction only those rays which proceed
from a point closer than six meters (20 feet) are
spoken of as divergent. This is also shown in
Fig. 21 as the rays diverge from the candle flame
and are also spoken of in this instance as incident.
Parallel Rays. The greater the distance of any
luminous point, the more nearly do its rays ap-
proach to parallelism; this is evident in a study of
rays coming from such distant sources as the sun,
moon and stars. For all practical purposes in the
study of refraction, rays of light which proceed
from a distance of six meters or more are spoken
of as parallel, although this is not absolutely cor-
rect, as rays of light at this distance still maintain
a slight amount of divergence. If the pupil of the
emmetropic eye is represented by a circular open-
ing four millimeters in diameter, then the rays of
light from a luminous point at six meters (6,000
millimeters) will have a divergence of 4/6,000
when they enter such a pupil.
Convergent Rays. Convergent rays are the re-
sult of refraction through a convex lens or reflec-
tion from a concave mirror. Convergent rays are
not a condition of nature. Fig. 22 shows the rays
of light converging as they emerge from the lens,
48 THE OPHTHALMOSCOPE.
and Fig. 23 shows the rays of light converging as
they rebound from the concave mirror.
A Beam of Light. This is a series or collection
of parallel rays. Fig. 22, if reversed, shows rays
of light diverging from a point and after refrac-
tion by the plano-convex lens are made parallel.
A Pencil. A pencil of light is a collection of
divergent or convergent rays. Convergent rays
are those which tend to a common point, whereas
divergent rays are
those which proceed
from a point. This
point is called a ra-
diant point. The
rays from the candle
FIG. 24.
flame in Fig. 24 form
a divergent pencil, the point in the flame is the
point of the pencil or the radiant point. The rays
of light coming together after leaving the lens, as
shown in Fig. 22, form a convergent pencil. The
point of this converging pencil is called a |oettsr
A Focus. This is the point of a converging or
diverging pencil. The center of a circle is also
spoken of as a focus. Focus means " fire," and
is referred to as the burning point of a convex lens.
There are two kinds of foci.
A Positive or Real Focus. This is the point to.
which rays of light are directed after passing
through a convex lens ( Fig. 22 ) , or- the point to
REFLECTION. 49
which rays of light are directed after reflection
from a concave mirror (Fig. 23). A positive or
real focus may be described as the actual meeting
ofrays of light; such a focus may be thrown upon
a screen.
A Negative or Virtual Focus. This is the
point from which rays appear to diverge after pass-
ing through a concave lens (Fig. 45) or after re-
flection from a convex mirror (Fig. 31) or after
refraction through a convex lens when the light
or object is closer to the lens than its principal focus
(Fig. 47), or after reflection from a concave mir-
ror when the light or object is closer to the mirror
than its principal focus (Fig. 28). A virtual or
negative focus cannot be thrown upon a screen.
Reflection. From the Latin " reflectere," to re-
bound. This is the sending back of the rays of
light by the surface on which they fall into the
medium through which they came. This is the
study of catoptrics (from the Greek x ( * T07rT P ov
meaning "a mirror"). While most of the rays
of light falling upon a transparent substance will
pass through it, yet some portion of the rays are
reflected and it is by virtue of these reflected rays
that surfaces are rendered visible. A substance
that could transmit or absorb all the rays of light
which came to it (if such a substance existed)
would be invisible. Fig. 33 shows a ray of light
incident on a piece of clear glass ; a portion of this
ray passes through, emerges and is refracted, but
6
5O THE OPHTHALMOSCOPE.
at the same time all of the incident ray did not
pass through the glass, a portion of it rebounded
or was reflected, and in this way the glass is made
or rendered visible. Likewise the ray P, while
it strikes the glass perpendicularly, a portion of
it passes through the glass and a portion rebounds
in the same perpendicular, and if the eye was look-
ing down onto or into or through the glass, the
glass itself would be rendered visible.
Laws of Reflection. ( i ) The angle of reflection
is equal to the angle of incidence. (2) The re-
flected and incident rays are in the same plane
with the perpendicular to the surface (Fig. 25).
The incident ray / falling upon the plane mir-
ror AB at D becomes
the reflected ray R.
The perpendicular line
P divides the angle
IDR into two angles of
n D
the same size, IDP
and RDP. The angle
of reflection RDP is equal to the angle of incidence
IDP. If the angle of incidence was made greater
then the angle of reflection would be greater, if
the angle of inpidence was made smaller then the
angle of reflection would also be made smaller.
The reflected ray R and the incident ray / are in
the same plane as the perpendicular P. The bril-
liancy of reflection is controlled by the quality of
the reflecting surface upon which .the light is inci-
REFLECTION FROM A PLANE MIRROR. 51
dent. Polished surfaces or surfaces light in color
reflect with great intensity, whereas rough sur-
faces or surfaces dark in color reflect very im-
perfectly.
Reflection from a Plane Mirror. Rays of light
are reflected from a plane mirror in the same di-
rection in which they fall upon it; if parallel, con-
vergent, or divergent before reflection, then they
are parallel, convergent or divergent after reflec-
tion. An object in front of a plane mirror appears
FIG. 26.
just as far back in the mirror as the object is in
front of it (Fig. 26). AB represents a plane mirror
with EF rays from the extremes of the object /
reflected from the mirror AB and meeting at the
observer's eye as if they came from the object /
in the mirror. The apparent distance of the object
7 (as pictured in the mirror) from the observer's
eye, is equal to the combined length of the incident
and the reflected rays. The appearance of an
52 THE OPHTHALMOSCOPE.
image in a plane mirror is not exactly the same as
that of the object facing the mirror; as it under-
goes what is known as lateraMnyersion. This is
best understood by holding a printed page in front
of a plane mirror, when the words or letters will
read from right to left (Fig. 27).
Spheric Mirrors. A spheric mirror is a portion
of a reflecting spheric surface; its center of curva-
ture is therefore the center of the sphere of which
it is a part. Spheric mirrors are of two kinds, con-
cave and convex.
.- *
-f
~T
R
E F
LEG
TION
fl
1 3
03J
HOIT
FIG. 27.
Reflection from a Concave Mirror (Fig. 28).
All rays of light that pass through the center of
curvature to a concave mirror are normals or per-
pendiculars at their points of incidence; in other
words, these rays of light always travel back and
forth on these same lines. With this clearly in
mind the reader can at once appreciate the fact that
each point on the surface of a curved mirror is
equivalent to a plane surface and reflects light ac-
REFLECTION FROM A CONCAVE MIRROR. 53
cording to the laws of reflection just mentioned.
Parallel rays are reflected from a concave mirror j
and are brought to a focus in front of it. This
focus is called the pmcipal__focus and is always!
situated at one-half the distance of the center of]
curvature. If the center of curvature is at four
inches, then the principal focus or focus for paral-
lel rays will be at two inches. If the center of cur-
vature is at ten inches, then the principal focus will
be at five inches, etc. The ray of light which passes
through the center of curvature and the principal
focus is called the principal axis. All other rays
which pass through the center of curvature are
called secondary axes. Rays of light which di-
verge from some point between infinity (twenty
feet) and the center of curvature will be reflected
by a concave mirror and brought to a focus
at a point between the principal focus and the
center of curvature. The reverse of this state-
ment is equally true, i. e., rays of light diverg-
ing from a point between the principal focus
and the center of curvature will converge at
some point between the center of curvature
and infinity. In other words, the point from
which rays of light diverge and the point to
which they converge are conjugate points, or foci.
These points are " yoked together." They are in-
terchangeable. In Fig. 28 if a point of light was
placed at / its rays after reflection would focus at G.
It has already been stated that parallel rays al-
54
THE OPHTHALMOSCOPE.
ways focus at the principal focus, then if a point of
light was placed at the principal focus, its rays after
reflection would pass parallel. Rays of light which
diverge from a point closer to a concave mirror
X
X
FIG. 28. CC, center of curvature ; 2'2 r 2'2', normals or radii of cur-
vature. /, PF and i indicate the principal axis.
than its principal focus, can never meet, as they
are reflected still more divergently, but if the eye
could intercept them they would be projected back-
ward to an imaginary point back of the mirror;
this point back of the mirror from which these di-
FIG. 29.
vergent rays appeared to come is spoken of as a
--virtual or negative focus (VV in Fig. 28).
Images Formed by a Concave Mirror. To
find the position of an image as formed by a
IMAGES FORMED BY A MIRROR.
55
concave mirror, two rays may be used to find each
individual point of the image: one drawn from a
given point in the object to the mirror, parallel to the
principal axis and reflected through the principal fo-
cus (Fig. 29) ; the other ray must be a secondary
axis from the same point, passing through the cen-
ter of curvature. The place at which the secondary
axis or ray and the reflected ray (or their pro-
jections) intersect will give the position of the
point in the image which corresponds to the given
point in the object. When finding the position of
FIG. 30.
an image, if the extreme points are found, then
the intermediate points must coincide. Unlike the
plane mirror, which produces images at all times
and all distances, the concave mirror produces
either an erect and virtual image if the object is
closer than the principal focus, or a real and in-
verted image if the object is placed beyond the
principal focus. If an object is at the principal
focus, then there will not be any image as the rays
would be reflected parallel. Fig. 29 shows an erect,
virtual image (ar) of AR which is closer than the
THE OPHTHALMOSCOPE.
I principal focus. Fig. 30 shows an inverted but
real image (ar) of AR which is placed beyond the
principal focus. When an object is situated at the
center of curvature its image is equally distant and
of the same size, but inverted.
Reflection from a Convex Mirror. All rays are
reflected divergently from a convex mirror, and
parallel rays diverge as if they came from the
principal focus situated behind the mirror at a dis-
tance equal to one-half its radius of curvature.
( The principal focus of a convex mirror is negative.
I The foci of convex mirrors are virtual.
Images Formed by Convex Mirrors. These
are always virtual, erect and smaller than the ob-
ject. A good illustration of a strong convex mir-
ror is the human cornea which the student may
\
C.(
FIG. 31.
observe in any patient or in his own eye. The
closer the object, the larger the image, and the
more distant the object, the smaller the image. In
Fig. 31 parallel rays from the object AR are re-
flected from the mirror as if they came from the
REFRACTION. 57
:
principal focus situated at half the distance of the
center of curvature CC. Lines drawn from th
extremes of the object to CC are secondary axes,
and the image is situated at the point of intersec-
tion of the secondary axes and the rays from the
principal focus; and as these meet behind the mir-
ror the image is smaller than the object, virtual
and erect.
Refraction. From the Latin " refrangere,"
meaning to " bend back " i. e., to deviate from
a straight course. Refraction may be defined as
the deviation which takes place in the direction of
rays of light as they pass from one medium into
another of different density. Or refraction is said
to take place when a ray of light passes obliquely
from one medium to another and is so bent or devi-
ated that its course in the second medium is at an
angle with its course in the first medium.
Two laws govern the refraction of rays of light :
1. A ray of light passing from a rare into a
dense medium is deviated or refracted toward the
perpendicular.
2. A ray of light passing from a dense into a
rare medium is deviated or refracted away from
the perpendicular.
A ray of light will continue its straight course
through any number of different transparent media,
no matter \vhat their respective densities may be,
so long as it forms right angles with the surface
or surfaces (Fig. 32). Such a ray is spoken of as
THE OPHTHALMOSCOPE.
the normal or perpendicular; such surfaces are
plane, the surfaces and perpendicular forming right
angles. Fig. 33 shows the perpendicular (PP) to
a piece of plate glass with plane surfaces. The
| ICE
<
/ FLINT GLASS
I
> CROWN "
f 1
3 PLATE '
^
>
FIG. 32.
ray in air incident at O on the surface SF is bent
in the glass toward the perpendicular PP. The
dotted line shows the direction the ray would have
taken had it not been re-
fracted. As the ray in the
F glass comes to the second
surface at R and passes into
a rarer medium it is deviated
from the perpendicular PP.
The ray now continues its
original course ; it has under-
9 gone lateral displacement.
Prism. A prism is any refracting substance
bounded by plane surfaces which intersect each
other. The sides of a prism are the inclined sur-
faces. The apex is where the two plane surfaces
meet.
SPHERIC LENSES. 59
Prismatic Action. Rays of light which pass
through a prism are always refracted toward the
base of the prism (Figs. 34 and 35). If an inci-
dent ray is perpendicular to one surface of a prism
then the second surface alone will refract the ray,
FIG. 34. FIG. 35.
but its direction after leaving the prism will be
toward the base (Fig. 34). Prisms do not form
images. Prisms have no foci. An object viewed
through a prism has the appearance of being dis-
placed and in a direction opposite to the base, i. e.,
toward the apex.
Lenses. There are two kinds of lenses used for
refraction purposes spheres and cylinders.
Spheric Lenses. Abbreviated S. or Sph.
Spheric lenses are so named because their curved
surfaces are sections of spheres. A spheric lens is
one which refracts rays of light equally in all me-
ridians or planes. Spheric lenses are of two kinds,
convex and concave.
A convex spheric lens is thick at the centre
and thin at the edge (Figs. 36, 37, 38). The fol-
lowing are synonymous terms for convex lenses:
6o
THE OPHTHALMOSCOPE.
(r) plus, (2) positive, (3) collective, (4) mag-
nifying. A convex lens is denoted by the sign
of plus ( + ).
Varieties or kinds of convex lenses:
A
FIG. 36. FIG. 37. FIG. 38.
1. Planoconvex, meaning one surface flat and
the other convex. It is a section of a sphere (Fig.
36).
2. Biconvex, also called convexoconvex or bi-
spheric, for the reason that it is equal to two plano-
convex lenses with their plane surfaces together
(Fig. 37).
3. Concavoconvex. This lens has one surface
concave and the other convex, the convex surface
having the shorter radius of curvature (Fig. 38).
The following are synonymous terms for a con-
cavoconvex lens: (i) periscopic, (2) convex men-
iscus, (3) converging meniscus (meniscus mean-
ing a small moon) (Fig. 38). A periscopic lens
enlarges the field of vision, and is of especial service
in presbyopia. A periscopic lens is also spoken of
as a toric lens.
A concave spheric lens is thick at the edge and
thin at the center (Figs. 39, 40, 41). The follow-
SPHERIC LENSES.
61
ing are synonymous terms for a concave lens : ( I )
minus, (2) negative, (3) dispersive, (4) minifying.
A concave lens is denoted by the sign of minus ( ).
Varieties or kinds of concave lenses:
i. Planoconcave, meaning one surface flat and
the other concave (Fig. 39).
7 V7
A i\
FIG. 39.
FIG. 40.
FIG. 41.
2. Biconcave, also called concavoconcave or bi-
concave spheric, for the reason that it is equal to
two planoconcave lenses with their plane surfaces
together (Fig. 40).
3. Convexoconcave. This lens has one surface
convex and the other concave, the concave surface
having the shorter radius of curvature (Fig. 41).
The following are synonymous terms for a concavo-
convex lens: (i) concave meniscus, (2) diverging
meniscus, (3) periscopic.
A spheric lens may be considered as made up
of a series of prisms which gradually increase in
strength from the center to the periphery, no matter
whether the lens be concave or convex.
In the convex sphere the bases of the prisms are
toward the center of the lens, whereas in the con-
62
THE OPHTHALMOSCOPE.
cave the bases of the prisms are toward the edge
(Figs. 42, 43).
FIG. 42.
Knowing that a prism refracts rays of light
toward its base, it may be stated as a rule that
every lens bends rays of light more sharply as the
FIG. 43.
periphery is approached, i. e., at the periphery the
strongest prismatic effect takes place.
Parallel rays of light passing through a convex
CONJUGATE FOCI. 63
lens come together at a point called the principal
focus (Fig. 44). This principal focus is also known
as the shortest focus. Parallel rays of light passing
through a concave lens diverge, as if they came
from a point on the same side of the lens as the
parallel rays, and this point is known as the princi-
pal focus of the concave lens (Fig. 45).
FIG. 44.
The action of a convex lens is similar to that of
a concave mirror, and the action of a concave lens
is similar to that of a convex mirror.
P.P.
FIG. 45.
Conjugate Foci. Lenses like mirrors have con-
jugate foci, conjugate meaning " yoked together."
The point from which rays of light diverge and the
point to which they converge are conjugate foci or
points; for instance in Fig. 46 the rays diverging
64 THE OPHTHALMOSCOPE.
from A and passing through the lens converge to
the point B, then the points A and B are conjugate
foci. They are interchangeable, for if rays diverge
from B they will follow the same path back
again and meet at A. The path of the ray
FIG. 46.
CC' is the same whether it passes from A .to
B or from B to A there is no difference. It is by
the affinity of these points for each other, with re-
spect to their positions, that they are called con-
jugate. The equivalent to conjugate foci is found
in the long or myopic eye, an eye in other words,
which has its fovea situated further back than the
principal focus of its dioptric media, the result be-
ing that rays of light from the fovea of such an
eye will be projected convergently after passing out
of the eye and will meet at some point inside of
infinity (twenty feet). The fovea of a myopic
eye represents a conjugate focus. A myopic eye
is in a condition to receive divergent rays of light
at a focus on its retina and to ^grnit convergent
rays.
Ordinary Foci. When rays of light diverge
from some point inside of infinity and beyond the
principal focus, they will be brought to a focus at
some point on the other side of a convex lens beyond
ORDINARY FOCI.
its principal focus; this point is called a conjugate
or ordinary focus. A lens may have many foci
but only two principal foci. When rays of light,
diverge from some point closer to a lens than its
FIG. 47.
principal focus, they do not converge but after re-
fraction continue divergently, their focus now be-
ing found by projecting these divergent rays back
to a point on the same side of the lens from which
they appear to come; this point is called negative
or virtual (Fig. 47). This is equivalent to what
takespace in a short or hypermetropic eye, an
eye which has its macula closer to its dioptric
media than its principal focus. In a state of rest
the fovea of such an eye would project divergent
FIG. 48.
rays outward and would be in a position to receive
only convergent rays of light at a focus upon its
fovea.
7
66
THE OPHTHALMOSCOPE.
Images Formed by Lenses. An image formed
by a lens is composed of foci, each one of which
corresponds to a point in the object. Images are
of two kinds, real and virtual.
A Real Image. This is an image formed by
the actual meeting of rays of light; such images
can always be projected onto a screen (Fig. 48).
FIG. 49.
A Virtual Image. This is one that is formed
by the prolongation backwards of rays of light to
a point. Such images cannot be projected onto a
screen; such images can only be seen by looking
through the lens.
.A'
FIG. 50.
Fig. 49 shows the arrow AB closer to the bi-
convex lens than its principal focus. An eye look-
ing through this lens at the arrow would see a
virtual, erect and magnified image of the arrow at
NUMERATION OF LENSES. 67
A'B'. Fig. 50, however, shows the arrow AR in
front of a concave lens and the eye looking through
this lens sees a virtual, erect and minified image of
the arrow at A'R'.
Numeration of Lenses. Formerly lenses were
numbered by the distance of the principal focus
from the center of the lens, as measured in English
inches, one inch being 25.4 millimeters. The unit
known as i, was a lens that would focus rays of
light at the distance of one inch. Half the unit
was written l /2 and was called the half inch, but
this means that the lens is one-half the strength
of the unit, and therefore focuses at twice the dis-
tance of the unit, viz., at two inches, and so the
old nomenclature numbered its lenses in fractions,
the denominator of the fraction signifying the prin-
cipal focal distance in inches.
The present system of numbering lenses is by
the diopter system, abbreviated D. The unit of
this system is a lens that will form a principal focus
at 40 inches (39.37 English inches). The strength
or refractive power of a dioptric lens is therefore
the inverse of its focal distance. The shorter the
focal distance the stronger the lens. To find the
focal distance of any dioptric lens in inches or cen-
timeters the number of diopters expressed must be
divided into the unit of 40 inches, or 100 centi-
meters; for example, a 2 D. lens has a focal dis-
tance of 40 divided by 2, equals 20 inches, or 100
centimeters divided by 2 equals 50 centimeters.
68
THE OPHTHALMOSCOPE.
Lenses that have a refractive power less than a
unit are not expressed in the form of fractions, but
in the form of decimals : for example, a lens which
is only one-fourth, one-half or three-fourths the
strength of the unit is written 0.25, 0.50, 0.75, re-
spectively.
To change the old nomenclature or inch system
of numbering lenses into diopters, divide the unit
(40 inches) by the denominator of the fraction,
and the result will be an approximation in diopters ;
for example, i/io equals 40/10, or 4 D. ; 1/20
equals 40/20, or 2 D.
Cylindric Lens. Abbreviated C, c or Cyl. A
cylinder lens receives its name from being a seg-
ment of a hollow or solid cylinder parallel to its
FIG. 51.
FIG. 52.
axis (Figs. 51 and 52). A cylinder is a lens which
refracts rays of light in one meridian only and
that meridian is always opposite to its axis. A
cylinder lens has no one common focus or focal
point, but a line of foci which is parallel to its axis
CYLINDRIC LENSES.
6 9
(Fig. 53). The dimension of a cylinder lens which
is parallel to the axis of the original cylinder, of
which it is a part, is spoken of as the axis and is
indicated on the lens by a short diamond scratch
at its periphery, or by having a small portion of
its surface corresponding to the axis ground at
FIG. 53-
the edges, or it may be marked in both ways (Fig.
54). Cylinders are of two kinds, convex and con-
cave. A convex cylinder converges parallel rays
FIG. 54.
of light so that they are brought into a straight line
which corresponds to the axis of the cylinder (Fig.
53). A concave cylinder diverges rays of light
opposite to its axis as if they had diverged from
THE OPHTHALMOSCOPE.
a straight line on the opposite side of the lens (Fig.
55).
FIG. 55-
Spherocylinders. A spherocylinder is a com-
bination of a sphere and a cylinder, and is there-
fore a lens which may have one surface ground
with a spheric curve and the other surface cylin-
dric. Spherocylinders therefore have two differ-
ent curves. The spheric curve may be convex
with the cylinder surface convex, or the spheric
surface may be concave with the cylinder surface
concave, or the spheric surface may be convex
with the cylinder surface concave, or the spheric
surface may be concave with the cylinder surface
convex, or, as in the toric spherocylinder, or two
cylinders of different strengths may be ground on
one surface and a sphere on the other surface.
As a plus sphere
will bring parallel
rays of light to a fo-
cus, then such a lens
(of proper strength)
if placed in front of
a hypermetropic eye
(Fig. 56) will increase the refraction of such an eye
FIG. 56.
SPHEROCYLINDERS.
and bring parallel rays of light to a focus on the
retina (Fig. 57), making the eye equivalent to what
is known as the standard or emmetropic eye (Fig.
58). The emmetropic eye is an eye therefore that
FIG. 57.
FIG. 58.
does not require any lens to make parallel rays
focus upon its retina.
As a minus sphere will diverge parallel rays of
light, then such a lens (of proper strength) if
placed in front of a myopic eye (Fig. 59) will give
parallel rays such an amount of divergence, that
when they enter the myopic eye they will focus on
FIG. 59.
its retina (Fig. 60), making it equivalent to the
emmetropic eye.
Astigmatism is the condition of an eye in which
parallel rays of light are not refracted equally in
all meridians, one meridian refracting stronger
72 THE OPHTHALMOSCOPE.
than the meridian at right angles, hence the use of
a cylinder lens which refracts rays in one meridian
only, and therefore diminishes or weakens the
stronger meridian in myopia ( cylinder) and in-
creases or strengthens the refraction in the weaker
meridian in hypermetropia (+ cylinder).
FIG. 60.
Estimating the Refraction of an Eye with
the Direct Method. For a close approximation
of the patient's refraction, the following essentials
should have very careful attention. The observer
should wear his own correcting glasses or make
due allowance for his error when reading the
findings at the sight-hole of the ophthalmoscope.
The observer must relax his accommodation, and
if possible the patient's accommodation should be
at rest with a reliable cycloplegic (atropin). The
use of " drops " is not so important in the aged.
The ophthalmoscope must be held close to the ob-
server's and patient's eye. With these matters
carefully executed, then the following statement
of facts will be correct.
Emmetropia. Seeing the fundus distinctly
without any lens at the sight-hole of the ophthal-
MYOPIA. /3
moscope, means that parallel rays are emerging
from the eye under observation, then passing
through the sight-hole of the instrument enter the
observer's eye and focus on his macula.
Hypermetropia. If a plus sphere must be used
at the sight-hole of the ophthalmoscope to see the
eye ground distinctly, then the eye must be hyper-
metropic and the amount of the hypermetropia is
represented by the strongest plus glass so employed.
The rays of light leaving the hypermetropic eye
divergently (Fig. 56) cannot focus on the ob-
server's retina without the aid of the plus glass,
or unless the observer is myopic ; or accommodates,
which he must learn not to do.
Myopia. If a minus sphere is used at the sight-
hole of the ophthalmoscope to give a clear view
of the fundus, which was otherwise indistinct, then
the eye under observation must be myopic and the
amount of the myopia is represented by the strength
of the weakest minus sphere so employed. The
rays of light leaving the myopic eye convergently
cannot focus on the observer's retina without the
aid of the minus sphere. If the observer had been
myopic two diopters and did not wear his glasses
and the eye under observation was also myopic
of the same amount, then the lens at the sight-hole
of the ophthalmoscope would have been minus four,
the amount of the observer's and the patient's error.
The same statement of facts would hold true if
they had each been hypermetropic, then the plus
8
74 THE OPHTHALMOSCOPE.
sphere at the sight-hole of the ophthalmoscope
would have recorded both errors. If the observer
does not wish to wear his refractive error, then he
must deduct the amount of his error from the
strength of the lens with which he sees the pa-
tient's eye ground distinctly.
Astigmatism. To estimate correctly the refrac-
tion of an astigmatic eye with the ophthalmoscope
is not an easy matter for the simple reason that the
observer cannot always relax his accommodation,
and furthermore the examination is limited princi-
pally to focusing the retinal vessels in different
meridians and these vessels do not always appear
at convenient places for this purpose. Astigmatism
is the condition of an eye in which there are two
principal meridians of different refracting power,
and these are usually at right angles to each other.
The observer with the ophthalmoscope must select
these two chief meridians for his observations. It is
impossible to estimate the refraction at the macula
as there are no vessels visible at this point, there-
fore the examinations are usually made with ves-
sels at or near the disc. The observer focuses a
selected vessel with the weakest minus or strongest
plus glass with which he can see it and makes a note
of its direction and then focuses another vessel (in
the same manner) as near a right angle position to
the first vessel as possible. The difference in
strength of these two lenses is the amount of the
astigmatism and represents the strength of the
ASTIGMATISM. 75
f cylinder lens necessary for its correction. The
observer must remember when making estimates
for astigmatic errors that when he sees a vessel
distinctly he is viewing it through the meridian op-
posite to its course, i. e., if the vessel is at axis ninety
he is seeing it through the horizontal meridian, if
the vessel is at axis one hundred and eighty he is
seeing it through the vertical meridian, etc.
Simple Hypermetropic Astigmatism. With
the formula -f 3.00 cyl. axis 90 degrees, the oph-
thalmoscope would reveal the horizontal vessels seen
without any glass, emmetropic, and the vertical ves-
sels with a plus three at the sight-hole.
Simple Myopic Astigmatism. With the for-
mula --2.00 cyl. axis 180 degrees, the ophthal-
moscope would reveal the vertical vessels without
any lens at the sight-hole (emmetropic) and the
horizontal vessels seen with a minus two.
Compound Hypermetropic Astigmatism. With
formula -f- 2.00 sph. C + i.oo cyl. axis 90 degrees.
Vertical vessels will be seen distinctly with + 3 and
the horizontal vessels with a + 2. The difference
between the chief meridians is + I, which is the
cylinder with its axis at 90 degrees and the + 2
would be the amount of the additional refraction
for all meridians.
Compound Myopic Astigmatism. With a for-
mula -- i.oo sph. C 3.00 cyl. axis 180 degrees,
the vertical vessels will be seen with - - i and
the horizontal vessels with - 4. The differ-
7 6 THE OPHTHALMOSCOPE.
ence between the two meridians would be -- 3.00
cyl. at axis 180 degrees. The --i would be the
amount of the additional myopia for all meridians.
Mixed Astigmatism. With the formula 2.00
sph. C + 5.00 cyl. axis 90 degrees, the vertical ves-
sels would be seen with a + 3.00 and the horizontal
vessels with 2.00.
Retinoscopy. This is a method of estimating
the refraction of an eye without viewing the details
of the fundus as in the direct method, and the ob-
server does not have to make any note of his ac-
commodation, although the patient's accommoda-
tion should be relaxed and his pupil widely dilated.
The observer may sit at any distance in front of
the patient, preferably at 40 inches, and reflect the
light into the patient's eye from the concave mirror
of the ophthalmoscope, or he may use a plane mirror
held in front of his eye. Gently rotating the mirror
as the patient looks towards the observer's fore-
head, the illumination seen in the patient's pupil will
appear to be stationary, not to move, or it will ap-
pear to move as the mirror is moved or it will ap-
pear to move in the opposite direction to that in
which the mirror is rotated, depending upon the
kind of mirror employed and the variety of the re-
fractive error.
Retinoscopy practiced with the plane mirror at
40 inches :
i. The faster the illumination appears to move
the weaker the refractive error.
RETINOSCOPY. 77
2. The slower the illumination appears to move
the stronger the refractive error.
3. The illumination appearing to be stationary
as the mirror is rotated, the refractive error will
be myopic i D.
4. The illumination appearing to move opposite
to the movement of the mirror, the refraction will
be myopic more than i D.
5. The illumination moving with the movement
of the mirror after a + i D. has been placed in
front of the eye means that the eye is hypermetropic.
6. The illumination appearing to move faster
in one meridian than another (usually the meridian
at right angles) signifies astigmatism.
7. When the illumination appears as a band of
light extending across the pupil, then the eye is as-
tigmatic.
Retinoscopy practiced with the concave mirror at
40 inches:
1. The apparent fast or slow rate of movement
of the illumination signifies respectively a weak or
strong refractive error.
2. No apparent movement signifies myopia of
i D.
3. The illumination appearing to move with the
mirror signifies myopia of more than i D.
4. The illumination appearing to move opposite
to the movement of the mirror while a + i D. is
in front of the eye signifies hypermetropia.
78 THE OPHTHALMOSCOPE.
5. The statements under 6 and 7 for the plane
mirror are equally true for the concave mirror.
Retinoscopy is certainly the simplest, most exact
and the easiest method to learn to estimate the re-
fraction.
CHAPTER III.
ANATOMY AND ANOMALIES OF THE EYE.
THE human eye is shaped like a sphere except
that it has a constriction on its anterior portion cor-
responding to the base of the cornea. The antero-
posterior diameter of the standard eye is 24.3 milli-
meters, transversely it is 23.6 millimeters, and
vertically 23.4 millimeters. The eyeball consists
of three tunics or coats, and within are two humors,
aqueous and vitreous, having the crystalline lens
between them (Fig. 61).
The tunics from without inward are:
1. The sclera and cornea.
2. The choroid, iris, and ciliary body.
3. The retina.
The media are the cornea, aqueous humor, crys-
talline lens and vitreous humor.
The aqueous humor occupies the corneal cavity
and lies in front of the lens while the vitreous
humor fills the cavity of the sclera, posterior to
the lens.
The Sclera (o-K\rjp6<s, "hard") or sclerotic coat
(c, Fig. 61) is thickest posteriorly (one millimeter)
and diminishes in thickness anteriorly (0.4 milli-
meter), where it is reinforced by the tendons of
the muscles. The sclera consists of bundles of fine
79
8o
THE OPHTHALMOSCOPE.
f
FIG. 61. HORIZONTAL SECTION OF THE RIGHT EYE. (Landois.)
a, Cornea ; b, conjunctiva ; c, sclerotic ; d, anterior chamber contain-
ing the aqueous humor ; e, iris ; //', pupil ; g, posterior chamber ; /,
Petit's canal ; j, ciliary muscle ; k, corneoscleral limit ; f, canal of
Schlemm ; m, choroid ; n, retina ; o, vitreous humor ; No, optic nerve ;
q, nerve-sheaths ; p, nerve-fibers ; Ic, lamina cribrosa ; h, crystalline
lens ; or, ora serrata ; pc, ciliary processes ; the line, OA, indicates the
optic axis ; Sr, the axis of vision ; r, the position of the fovea centralis ;
Kn, nodal point ; x, equator of lens ; t, external rectus muscle ; s, inter-
nal rectus muscle ; Z, optic nerve-sheath ; H, sclerotic.
THE CORNEA. 8 I
fibrillse of connective tissue which form in circles,
some corresponding to the equator and others run-
ning meridionally. The sclera, pearly white in
color, contains in its deeper portion some pig-
ment cells. While the sclera has very few vessels
of its own, yet it is traversed by vessels and nerves
which pass into the interior of the eye. The scleral
coat is anatomically a continuation of the sheath
of the optic nerve, which sheath is itself continuous
with the dura mater. The sclera, by virtue of its
thickness, toughness, and hardness, assists in giv-
ing the eyeball its shape, and is a protection to
the structures within. Posteriorly, and about 10
degrees to the nasal side of the center, the sclera
contains an opening (about two millimeters in di-
ameter) called the scleral opening (foramen
sclerae) for the entrance of the optic nerve fibers.
The scleral coat is also perforated by the venae
vorticosae and by the posterior and anterior ciliary
arteries and nerves.
The Cornea. (/ce/>a9, horn) (a, Fig. 61). This
structure together with the sclera, forms the outer
fibrous tunic or coat of the eye. The cornea in
health represents a section of a transparent sphere
with a radius of curvature, normally of 7.8 milli-
meters on its anterior surface. The posterior
radius of curvature is about 7.^ millimeters. These
normal radii are seldom found as most eyes have
corneal astigmatism. The diameter of the base of
the cornea is about 12 millimeters horizontally, and
82 THE OPHTHALMOSCOPE.
1 1 millimeters vertically, as the scleral tissue over-
laps the cornea on its upper and lower edges. As
the diameter of the eyeball itself is 24 millimeters
(radius 12 millimeters), then the cornea with its
shorter radius must adjust itself to the sclera as a
watch crystal on a watch. This can be seen with
a magnifying glass by close observation of any
healthy eye, as the white sclera is then seen to ex-
tend over onto the transparent cornea ; this is usu-
ally more conspicuous above and below, giving the
cornea the appearance of a horizontal ellipse. The
cornea is thicker at its edge than at its center. As
just stated, the cornea and sclera are very similar
in their anatomic construction and are continuous
structures, though one is transparent and the other
is not; the cornea has a different arrangement of
its fibrous network and the character of its cells is
different from the sclera also.
The cornea is made up of the following layers:
1. The Anterior- Epithelium. This consists of
several layers of pavement epithelium, the super-
ficial are flattened, the deep cells are cylindrical and
between these layers the cells are more or less
rounded. This epithelial layer is virtually a con-
tinuation of the conjunctiva and is sometimes
spoken of as the conjunctiva of the cornea.
2. Bowman's Membrane, also called the anterior
elastic membrane. This thin homogeneous mem-
brane lies beneath the epithelium; it is firmly at-
VESSELS. 83
tached to the underlying stroma and is a part of the
cornea proper.
3. The Stroma or Cornea Proper (Substantia
Propria). This represents the major portion of
the cornea and is continuous with the sclera. It
contains, or is made up of, bundles of fibers of
connective tissue arranged in lamellae. Between
these lamellae are spaces containing lymph, hence
they are called lymph spaces, and are connected with
each other by narrow openings called canals. Nor-
mally the cornea does not contain blood vessels.
4. Descemet's Membrane. Posterior-elastic
membrane. As Bowman's membrane forms the
anterior portion of the cornea proper, so Desce-
met's membrane forms the posterior, and while
Bowman's is quite intimately adherent to the
stroma, yet Descemet's membrane is not so. This
latter is very dense or tough and by virtue of its
toughness it is a protection for the eye against
penetrating diseases of the cornea. Descemet's
membrane may be considered as a part of the uvea
or inner tunic of the eye.
5. The fifth layer of the cornea, known as the
posterior pavement or endothelial layer, .is but a
single layer of cells more or less flattened, and
these cells, like Descemet's membrane, are a part
of the uvea, and with Descemet's membrane pre-
vent the aqueous fluid from passing into the stroma.
Vessels. The cornea in health is non-vascular.
It receives its nutrition from the anterior ciliary
84 THE OPHTHALMOSCOPE.
vessels which form a network of loops at the mar-
gin (limbus) of the cornea. Plasma passes from
the loops of the vessels into the lymph spaces
or canals in the cornea, and in this way the cor-
nea is nourished.
Nerves. The epithelial cells, Bowman's mem-
brane and anterior lamellae of the cornea proper,
contain numerous fine nerves, branches from the
long ciliary and nerves of the ocular conjunctiva.
Minute branches perforate Bowman's membrane
from the stroma and pass freely to the epithelial
layer. This network of nerves acts as a protec-
tion to the cornea, by giving it extreme sensibility
to all external injurious influences. The cornea
being transparent, and a section of a small sphere,
refracts the rays of light as they enter the eye and
with the assistance of the crystalline lens brings
parallel rays to a focus at the macula in a standard
eye. In fact, the cornea is the most important re-
fractive media of the eye.
The middle tunic of the eye consists of the
choroid, iris and ciliary body (commonly called
the uveal tract).
The Choroid. (xopioeiS^s ; Latin " corium,"
skin) (m, Fig. 61). The choroid is known as the
vascular coat, is brown in color and lies between
the sclera and the retina, and extends from the
edge of the optic nerve posteriorly w 7 here it is 0.16
millimeter in thickness, to the ora serrata (or. Fig.
6 1 ) anteriorly, where it is 0.08 millimeter in thick-
THE CHOROID. 85
ness. It has a few attachments to the sclera by the
lamina fusca. Posteriorly it is perforated by a
round opening known as the foramen choroid,
through which pass the optic nerve fibers and ves-
sels. The choroid has two principal attachments;
at the margin of the optic nerve entrance (the
region of the posterior ciliary arteries) and at the
equator of the eye, where most of the venous blood
passes out of the eye (venae vorticosse). Anatomic-
ally the choroid is made up of five layers.
1. Externally and next to the sclera a layer
known as the suprachoroid, which is rich in pig-
ment.
2. The inner layer, lamina vitrea, not pigmented,
lies next to the retina. Between the suprachoroid
and the lamina vitria are three layers of vessels;
from without inward these are: (a) the layer of
large vessels, (b) the layer of medium sized ves-
sels, (c) the layer of capillaries (chorio-capillaris).
The layer of large vessels is made up mostly of
large veins which lie very close together and anas-
tomose freely; the spaces between the vessels are
filled more or less with pigment cells. The
amount of pigment varies in different eyes, being
abundant in mulattoes and brunettes, and much
less so in blondes and possibly entirely absent in
albinos.
The layer of medium size vessels is not as thick
as the layer of large vessels and is not as heavily
pigmented. The capillary layer, as its name implies,
86 THE OPHTHALMOSCOPE.
is made up of capillaries, but of large caliber and
yet without pigrnented interspaces. The choroidal
circulation and choroidal pigment influence greatly
the color of the fundus reflex described in Chapter
IV. The pigment cells of the choroid are branched
and anastomosing. The choroid is not supplied
with sensory nerves. The posterior ciliary arteries
supply most of the blood to the choroid. The veins
of the choroid run nearly parallel to each other,
but finally converge into six or eight large trunks
(veriae^voxtieosje) and pierce the sclera obliquely
near the equator, and carry the blood from the
choroid.
The short ciliary arteries are the chief supply
of the choroid, and they number four or six small
vessels or branches from the ophthalmic artery.
These break up into about twenty branches, pierc-
ing the sclerotic around the optic nerve. The
function of the choroid by virtue of its great vas-
cularity is to nourish the retina, vitreous and lens
and to furnish the visual purple, and by its pigmen-
tation to make the interior of the eye a dark cham-
ber or camera.
The Iris (rainbow-shaped). This forms the
anterior portion of the uveal tract and is described
as a membranous curtain, disc-shaped and per-
forated slightly to the nasal side of its center by
a round opening called the pupil; this opening is
normally about 3^2 millimeters in diameter. The
diameter of the iris is about n millimeters and at
THE IRIS. 87
its margin is attached to the ciliary body, of which
it is anatomically a part. Normally the pupillary
margin of the iris is always in contact with the
anterior capsule of the lens, whether the pupil be
dilated or contracted. The aqueous humor lies
posterior to the cornea and anterior to the lens.
The iris divides the aqueous humor into two parts,
known as the anterior and posterior chambers, and
these two chambers are in communication through
the pupil. Anatomically, the iris is made up of
blood vessels and a fibrous connective tissue, to-
gether with the pigment cells and the sphincter of
the iris. The endothelial lining membrane of the
cornea and Descemet's membrane are continuous
onto the anterior surface of the iris up to its
pupillary margin; this covering of endothelial
cells is not complete on the iris for at various points
it is missing, and at these points there are depres-
sions in the iris stroma called crypts. The posterior
surface of the iris is lined with pigment called the
retinal pigment, and this continues well forward
into the pupillary edge of the iris, where it becomes
quite conspicuous in some eyes and in some dis-
eases of the iris and occasionally with cataract.
Lying next to the retinal pigment of the iris is the
dilator of the pupil; this is not muscular tissue but
an elastic tissue made up of fibers extending radi-
ally from the pupillary edge of the iris to its
periphery. Close to the pupillary edge of the iris,
and within the iris stroma is found the sphincter
THE OPHTHALMOSCOPE.
of the iris; this is muscular tissue, flat and about
one millimeter in width. Viewing the iris on its
anterior surface it is found to be uneven or filled
with ridges, elevations and depressions, and at its
periphery are seen concentric circles; these latter
are the folds made by the iris when the pupil dilates.
The ridges are formed by blood vessels. The iris
pigment is of two kinds, one the pigment in the iris
stroma, and the other, the retinal pigment layer.
The color of the iris is controlled in great part by
the amount of its pigment. The pigment in the
retinal layer is always quite abundant, whereas that
in the stroma varies considerably. If the stroma
does not contain any pigment or only a small
amount, then the retinal pigment layer shows
through the stroma, giving the iris a blue color.
The gray iris is seen when the stroma, free from
pigment, is quite thick. The dark iris (brown,
hazel, etc.) means that the stroma contains pig-
ment. Blondes usually have light-colored irises and
mulattoes or brunettes dark-colored irises, show-
ing that usually the pigmentation of the iris is
consistent with the eye ground and body pigmen-
tation.
Arteries. The long posterior ciliary and the
anterior ciliary, and branches of the muscular
arteries supply the iris with blood, forming a large
circle at the periphery of the iris and a small circle
near the pupillary margin. Many arteries pass
radially from the periphery to the pupillary edge
CILIARY BODY. 89
of the iris. The direction of these vessels has al-
ready been incidentally referred to in the descrip-
tion of the iris.
Nerves. The iris is supplied by a motor branch
from the third pair of nerves, and with sympathetic
fibers from the ciliary^ganglion. The iris does not
contain ganglion cells. The function of the iris is
to control the amount of light entering the eye.
Ciliary Body (cilia, " lashes," and so-called
from radiating folds seen on the surface of the
ciliary body) (/, Fig. 61 ) . Also from KVK\OS, mean-
ing a circle. The ciliary body in section is triangu-
lar in shape, the base of the triangle being shorter
than the sides, which are about 3 millimeters in
length. The ciliary body lies beneath the sclera and
just back of its junction with the cornea. A width
of sclera about 4 millimeters, extending back from
the edge of the cornea, covers the ciliary body ; this
width is called the pericorneal or dajigejv^one. The
outer side of the ciliary body, that next to the sclera,
is formed by the ciliary muscle and the inner side
is formed by the ciliary processes. The base of the
triangle faces forward toward the cornea and at
its center gives attachment or origin to the iris.
Near the apex of this triangular body, on its inner
surface, are the ciliary processes, about seventy in
number, and lighter in color than the rest of the
ciliary body, which appears black. The ciliary body
is attached to the scleral corneal junction by the
ligamentum pectinatum. In the ciliary body next
9
9O THE OPHTHALMOSCOPE.
to the sclera is found the ciliary muscle with its
many layers of muscular fibers. The longitudinal
or meridional fibers, known as the tensor choroidise,
or muscle of Briicke pass backward to be inserted
into the external layers of the choroid. Lying
beneath the tensor choroidiae fibers and crossing
them here and there are found the circular or
sphincter fibers, the muscle of Miiller. This is
called the compressor lentis. Many other muscular
fibers are also found in the ciliary body, but the
two just mentioned are the principal ones considered
in the act of accommodation. The ciliary processes
are covered and filled in with pigment and contain
r a great number of blood vessels. The ciliary body
is supplied by the posterior and anterior ciliary
arteries. Some of the veins of the ciliary body and
all of those of the iris empty eventually into the
vena vorticosse, while a few of the veins from the
ciliary muscle pass out through the sclera. The
nerves of the ciliary body, besides motor branches,
are many sensory branches from the trigeminus.
Uvea and Uveal Tract. If the sclera and cor-
nea and optic nerve can be removed from an eye,
then the remaining choroid, ciliary body and iris
being exposed show the pupillary opening anteri-
orly, and the opening for the optic nerve posteriorly.
These three structures, on account of their dark
color, somewhat resemble a grape (uvea), hence
called the uvea or uveal tract.
The Retina. (Reta, net) (n, Fig. 61). This
THE RETINA. 9 1
is the inner tunic or coat of the eye, the end organ
of the optic nerve. In health the retina is a trans-
parent membrane and is held in contact with the
choroid by the vitreous humor. The retina is at-
tached at the optic nerve posteriorly and at the ora
serrata anteriorly ; also at the f ovea centralis, where
it adheres slightly to the choroid. The optic nerve
fibers spread out in all directions from the disc and
pass through the layers of the retina, having their
terminal endings, the rods and cones, at the exter-
nal surface of the retina. The retina may be sub-
divided into ten layers, but the principal tissues of
which the retina is composed are the nervous and
supporting. The ten layers of the retina are :
1. Pigment layer.
2. Layer of rods and cones.
3. Membrana limitans externa.
4. Outer granular layer.
5. Fiber layer of Henle.
6. Outer reticular layer.
7. Inner granular layer.
8. Inner reticular layer.
9. Ganglion-cells layer.
10. Nerve fiber layer.
As the sclera is considered a continuation of
the dura mater, so the nerve fiber layer of the
retina may be considered an expansion of the brain.
The part of the retina corresponding to the optic \
nerve entrance is known as the disc, or nerve head, I
or papilla.
92 THE OPHTHALMOSCOPE.
Pigment Layer of the Retina. This is called
the tenth layer of the retina, and lies next to the
choroid. It is a most important layer or part of the
retina as it is a guide to the observer with the
ophthalmoscope, and suggests the separation or
line of demarkation between the retinal and cho-
roidal structures during any inflammation affecting
either one. The pigment consists of six-sided cells
and in a single layer; the cells are separated by a
clear or transparent space, and each cell is pig-
mented to only one-half its thickness (1/500 of a
line) ; the cell itself is therefore 1/250 of a line in
thickness. This is important to know and appre-
ciate, as it explains the coloring of the fundus re-
flex as coming from the choroid and not from the
retina, this pigmentation not being sufficient in it-
self to entirely conceal the choroidal reflex.
The Lens, also called crystalline body. Nor-
mally the lens is without color and transparent, bi-
convex in shape, with a longer radius on the an-
terior than on the posterior surface, the former
being about 10 and the latter 6 millimeters. The
lens is held in place by its own ligament (liga-
mentum suspensorium lentis, or zonula of Zinn).
The edge or equator of the lens is about .5 milli-
meter from the ciliary processes. At rest the lens
is 8.7 millimeters in its equatorial diameter, and 3.6
millimeters in its anteroposterior diameter on its
axis, from pole to pole. The center of the lens is
called the nucleus, and the remaining portion is
THE LENS. 93
called the cortex. The nucleus of the lens is a hard-
ening or sclerosis which begins to form at the
center of the lens soon after birth, and gradually
increases until old age (about seventy years),
when the entire lens may be said to be sclerosed, or
hardened, or to become all nucleus. Sclerosis does
not mean a loss of transparency, though the lens
may become amber colored as age advances. It is
this gradual hardening of the lens from its center
to the periphery that causes in great part the loss
of accommodation which takes place from youth to
old age. The lens is made up of long six-sided
fibers which pass to and from the anterior and
posterior surface of the lens. These fibers are held
together by outward pressure and also by a cement
substance (liquor Morgagni). The anatomy of the
lens may be described as made up of three primary
sectors, giving it a Y-shape and these prongs of
the Y are still further branched, making the Y
something of a star figure, called the " lens star."
The lens is surrounded by its transparent capsule.
That portion of the capsule on the anterior surface
is called the anterior capsule, and that on the pos-
terior surface is called the posterior capsule. The
anterior capsule is thicker than the posterior and
has a layer of epithelial cells lining its inner sur-
face, and it is from these cells that the lens fibers
have their origin. The lens is without nerves or
vessels and is said to receive its nourishment by
osmosis. The lens ligament is a thin, fibrous mem-
94 THE OPHTHALMOSCOPE.
brane, having its origin at the ciliary body and
many of its fibers may be traced to the ora ser-
rata. As these fibers pass from the ciliary processes
part of them adhere to the anterior capsule and part
to the posterior, and some few to the capsule at
the equator of the lens. The triangular space at
the equator of the lens formed between the an-
terior and posterior fibers of the ligament is called
the canal of Petit. The function of the lens is to
maintain the focus at the macula of rays of light
entering the eye from various distances at differ-
ent times.
The Vitreous (corpus vitreum, meaning a body
of glass) is a transparent, colorless substance of the
consistency in health of gelatinjelly, and fills the
large posterior or scleral chamber of the eye. It
lies in contact with the optic disc, the retina, ciliary
body and lens, the latter with its capsule resting
in a depression in the vitreous called the fossa patel-
laris. The vitreous is made up of round and
branched cells, and, like the lens, does not contain
blood vessels or nerves. It receives its nourishment
from the choroid, the ciliary body and vessels of
the retina. The vitreous is surrounded by a very
thin, transparent, structureless membrane called the
lrv_aloid. During intra-uterine life the vitreous is
perforated in its antero-posterior axis by the hy-
aloid artery and vein which pass from the disc to
the posterior surface of the lens. These vessels
normally become absorbed before birth, but in their
OPTIC NERVE. 95
place there remains a canal known as a lymgh chan-
nel. Canal of Cloquet. Normally this cannot be
seen with the ophthalmoscope.
Optic Nerve. The nerve is covered in its course
from the optic foramen by a loose sheath ((jural
sheath) which is continuous with the dura mater.
This sheath, as already stated, is also continuous
with the sclerotic coat. Immediately surrounding
the nerve is the gial_5liajh, which is continuous
with the pia mater. This pial sheath sends pro-
longations in between the bundles of nerve fibers
and extends as far forward as the lamina cribrosa.
As the outer sheath covers the nerve loosely and
the pial sheath beneath adheres closely, there is
left an intervening space known as the intervaginal,
containing a portion of the arachnoid, and this
space is continuous posteriorly with the subarach-
noid within the cranium, but anteriorly at the
membrana cribrosa it is more or less of a cul-de-
sac. The arachnoid membrane contains many mi-
nute openings, and it is by means of these openings
that the spaces each side of the arachnoid are in
free communication one with the other. Each optic
nerve fiber (about 500,000 in all) has its own indi-
vidual sheath (white matter of Schwann) until it
comes to the membrana cribrosa (Ic, Fig. 61), and
here each fiber loses its covering and collectively
these fibers pass through the foramen sclera and
go to assist in the formation of the retinal fiber
layer.
96 THE OPHTHALMOSCOPE.
Lamina Cribrosa (Ic, Fig. 61), meaning sieve-
like, is composed of fibers from the sclera and some
from the pial sheath. These fibers traverse the
foramen sclera and serve as a support to the intra-
ocular contents and also to the optic nerve fibers.
Blood Vessels. The posterior ciliary arteries
perforate the scleral coat around the entrance of
the optic nerve where it enters the sclera, arid these
vessels send off branches which anastomose and
form an arterial circle called the circle of Haller.
From this circle fine twigs pass between the trans-
parent nerve fibers which lie anterior to the mem-
brana cribrosa, and they in turn anastomose with
branches from the central vessels of the nerve.
From this description the reader will understand
and appreciate the circulation which takes place in
the nerve head and that the vascularity of the disc
is connected with the choroidal as well as with the
.retinal system of vessels. The central artery of
[the retina is a branch of the ophthalmic which comes
[from the internal carotid. The retinal vein empties
into the ophthalmic vein and thence into the cavern-
ous sinus.
Optic Disc. The optic nerve fibers having
dropped their sheaths before passing through the
membrana cribrosa must also pass through a round
opening in the choroid (foramen of the choroid)
before they can spread out to form the fiber layer
of the retina. The foramen choroid is a distinct
opening in the choroid and this opening usually
OPTIC DISC. 97
surrounds these fibers quite closely, but there are
many exceptions to this statement, for the foramen
choroid may be quite large and not embrace the
fibers closely, or it may touch the fibers at one side
only. The nerve fibers in the foramen choroid are
quite closely bunched together, and therefore as
they begin to separate they must bend almost at
right angles over the edge of the choroid to pass
into the retina. This bunching of all the nerve
fibers just where they bend and begin to separate
must form a prominence or elevation, and hence
another name for the optic nerve head is papilla.
As the fibers of the nerve head are transparent in
health it is not an easy matter to demonstrate this
elevation with the ophthalmoscope, consequently
some authorities dispute the correctness of the word
papilla and state that the optic nerve head is not
elevated, but is on a level with the surrounding eye
ground. It is at the disc that the blood enters and
leaves the retina. The disc is slightly to the nasal
side of the posterior pole of the eye.
The Macula. To the temporal side of the pos-
terior pole of the eye is found an area of most
acute vision (macula lutea) and at its center is a
depression which is circular or crescent or oval in
shape. This point is known as the center of sight
or "yellow spot," or fovea centralis; it is about
one millimeter in diameter (Plate I.).
Circulation at Macula. The macula is the most
vascular part of the retina. This is demonstrated
10
98 THE OPHTHALMOSCOPE.
by the microscope, but the fovea (center of the
macula) itself has no vessels^ .Plate I.).
While it has been stated that the retina extends
forward to the ora serrata, yet some portion of the
retina may be traced forward onto the ciliary proc-
esses and also onto the posterior surface of the iris.
The distance from the center of the disc of the em-
j metropic eye to the macula is 4 millimeters. The
thickest part of the retina is on the disc, 0.42 of a
millimeter; at the ora serrata it is 0.14 of a milli-
meter, and at the fovea o.i millimeter. The arteries
of the retina are branches of the central artery and
can be traced forward to the ora serrata, but they
are terminal vessels and do not anastomose. The
large vessels are in the nerve fiber layer beneath the
internal limiting membrane, therefore in that part
of the retina nearest the vitreous. The smaller ves-
sels of the retina extend as deep as the internal
granular layer. The fovea and external layers of
the retina are non-vascular and are nourished by
plasma from the chorio-capillaris. The circulation
of the retina is described in Chapter IV. The func-
tion of the retina is to convert the rays of light from
external objects into nervous stimuli. The macula
differs from the rest of the retina in that it is com-
posed entirely of cones closely packed together and
each cone is the terminal of a single nerve fiber, and
it is these cones in this area which have the most
acute vision, whereas in the periphery of the retina
the cones are not so numerous, the rods predomi-
CONGENITAL ANOMALIES. 99
nating, and the retinal fibers have several terminals
instead of only one, as at the macula.
Congenital Anomalies.
To avoid errors in diagnosis the observer should
be prompt to recognize variations from the stan-
dard condition known as anomalies.
Cornea. Congenital anomalies of the cornea are
extremely rare, and are usually recognized as opaci-
ties. These may or may not be vascular. The
cornea of the young embryo is opaque and gradu-
ally becomes transparent toward the time of birth,
but if for any reason this process is interrupted the
infant may be born with an opacity of the cornea.
Or if an ulcer of the cornea took place during intra-
uterine life an opacity may be recognized soon after
birth. Dermoid tumors are occasionally seen and
are situated at the corneo-scleral margin.
Microphthalmos (small eye), or an undevel-
oped eye, is occasionally observed, and in this con-
dition the cornea is correspondingly small.
Sclerophthalmia is another rare congenital con-
dition in which the sclera encroaches on the cornea,
so that there is not the usual amount of clear cornea
observed.
Iris. As the color of the iris is so varied in dif-
ferent people and races the color itself cannot be
said to be anomalous, but when an iris is variously
colored it is spoken of as heterochromia iridis. Or
if an eye has a different colored iris from its fellow
IOO THE OPHTHALMOSCOPE.
then the condition of the two eyes is spoken of as
heterophthalmos. Occasionally an iris has a few
or many pigment spots (black or brown) scattered
through it, and such an iris is spoken of as resem-
bling a leopard or tiger skin, called spotted or pie-
bald iris. Rarely one or both eyes may not have
an iris, and this is spoken of as irideremia or an-
iridia, and such an eye will naturally have defective
vision, and not unusually it is nystagmic.
Congenital Ectropion of the Uvea. This is a
rounded mass of the uveal layer projecting around
the pupillary edge of the iris onto the anterior por-
tion of the iris.
Rarely one or both eyes may have a cleft in the
iris, and this is called a coloboma (/coXd^w/xa, " mu-
tilation "). This usually appears in the lower por-
tion giving the pupil a shape not unlike a keyhole
in a door, and hence is sometimes called a " key-
hole " pupil. This being a congenital condition it
must be differentiated from a coloboma due to an
iridectomy, and this latter is usually made in the
upper portion of the iris (an inverted keyhole).
There is also an incomplete coloboma occasionally
seen not extending to the ciliary margin. Colo-
boma of the iris may occur in one or both eyes ; if
found in one eye it is usually the left. Coloboma of
the iris is occasionally associated with a similar con-
dition in the lens and choroid.
Pupil. Normally the pupil lies a trifle to the
nasal side of the center of the iris, and while this
THE PUPIL.
101
is quite difficult to recognize, yet there is a con-
genital condition in which the pupil is markedly
displaced, and this condition is promptly detected.
This displacement may be in any portion of the
iris and is spoken of as corectopia or ectopia pu-
pillae. Corectopia may affect both irises symmetric-
ally, and it has been known as a family charac-
teristic.
Occasionally an iris is seen having more than one
pupil and this condition is called polycoria. The
FIG. 62. Varieties of Persistent Pupillary Membrane. (Wickerkie-
wicz. 1 )
additional pupil may be situated very near the nor-
mal pupil. Another congenital condition sometimes
observed occupying the pupillary area is what is
1 Sojous Annual.
102
THE OPHTHALMOSCOPE.
known as pupillary membrane (Fig. 62). This
may appear as a few dark threads or as a broken
mass of pigment with many shreds passing across
from the anterior capsule of the lens in the pupillary
area and attached to the small circle of the iris.
Capsule pupillary membrane is a portion of pupil-
lary membrane seen extending from the iris to the
anterior capsule of the lens and if not carefully in-
spected with a magnifying lens or loupe, could be
FIG. 63. Various forms of Opacity of the Lens. The upper row as
they appear by Oblique Illumination. The lower row as seen by Trans-
mitted Light (Direct Method). By oblique illumination the opacity is
seen in its true color.
i, Anterior polar cataract ; 2, posterior polar cataract ; 3, lamellar
cataract ; 4, early stage of senile cataract ; 5, senile cataract not quite
mature or ripe, for if the light is thrown on the eye from the right
side the iris casts a shadow in the lens ; 6, subluxation of the lens.
(Jennings.)
mistaken for a posterior synechia. Pupillary mem-
brane is the remnant of the vascular membrane
which encircles the lens in intra-uterine life and fails
to become absorbed before or shortly after birth.
CATARACT. . 103
Cysts and naevi of the iris have been noted as con-
genital anomalies.
Lens. Rarely an eye may be born without a
lens (congenital aphakia). Congenital anomalies
of the lens are usually in the form of cataract as
follows :
Anterior Polar Cataract (No. I, Fig. 63). At
the anterior pole of the lens is seen a small white
spot the size of a pin point or a pin head ; it usually
involves the capsule and in many instances is pyra-
midal in shape and is sometimes called pyramidal
cataract. This variety of cataract is a congenital
condition and may be caused by a perforation of
the cornea in intra-uterine life or early infancy,
and may be associated with inter-pupillary mem-
brane. If carefully looked for, the corneal opacity
may usually be found.
Posterior Polar Cataract (No. 2, Fig. 63).
This variety of opacity, as its name implies, is in
the posterior portion of the lens, and if anything, a
trifle to the nasal side of the pole. It is somewhat
star-shaped and has been called " stellar cataract."
Just as interpupillary membrane showing on the
anterior capsule is the result of unabsorbed blood
vessels, so posterior polar cataract is said to be
caused by a portion of an unabsorbed vessel wall
at this point.
Lamellar, or Zonular, Cataract (No. 3, Fig.
63). As its name implies, this is a variety of cat-
aract characterized by a layer or zone of the lens
IO4 THE OPHTHALMOSCOPE.
being opaque and the remaining portion clear; in
other words, the nucleus may be clear and also the
cortex, but the intermediate portion is opaque;
hence this particular variety is also correctly called
perinuclear cataract. There are many departures
from this condition. This variety of cataract is
usually a condition at birth.
Congenital dislocation of the lens (No. 6, Fig.
63). This is usually a partial dislocation and
therefore not complete. Some portion of the lens
usually occupies a part of the pupillary area. This
condition is spoken of as ectopia lentis. The lens
is usually dislocated upward and this is usually a
condition of both eyes. Coloboma of the lens is not
common, but does occur and is frequently present
with coloboma of iris and choroid. Double colo-
boma of the lens has been reported. Carefully ex-
amined it appears to be a slight notch in the edge of
the lower portion of the lens, and sometimes as
much as one-quarter of its substance.
Lenticonus. This rare anomaly is a conic con-
dition of the lens at the center of its anterior or
posterior surface, usually the latter. With the
retinoscope (plane mirror) or the concave mirror
of the ophthalmoscope, or by oblique light, this
cone may be seen, as it resembles a drop of oil at
the point mentioned.
Choroid. The principal congenital anomaly of
the choroid is that of coloboma (coloboma cho-
roidese), which usually includes a corresponding
CHOROID. 105
section of the retina, and it is not unusual to have
the coloboma of the iris also present. Coloboma of
choroid is an arrest of development in the eye in
intra-uterine life before the choroidal fissure has
become closed. This condition is recognized just as
hare-lip and cleft palate are recognized, as congeni-
tal anomalies, and occasionally as an hereditary con-
dition. Coloboma of the choroid is of course seen
with the ophthalmoscope and is recognized by its
triangular shape, apex toward or embracing the
nerve head and the base of the triangle at the ciliary
processes. The white sclera shows brilliantly
where the choroid and retina are absent and a few
ciliary vessels are seen in the area of the coloboma
and scattered pigment about the sharp cut edges of
the coloboma. If the coloboma of the choroid exists
alone the presence of the retina is recognized as a
thin gauzy veil covering the cleft as also the retinal
vessels passing over it. Coloboma of the choroid
is not always complete, and is not always triangular
in shape. It may be round or oval and may include
the nerve head, or it may occupy the macula, and is
then called a macular coloboma. The coloboma
including the disc appears as a cleft or depression
and is usually in the lower portion, or the entire
nerve head may appear abnormally large. The
field of vision is cut off, corresponding to the colo-
boma (Chapter VI.).
Persistent Hyaloid Artery. In embryonic life
the central artery of the retina sends a branch for-
106 THE OPHTHALMOSCOPE.
ward through the central portion of the vitreous,
Canal of Cloquet, to the posterior surface of the
lens, and here it branches and covers the lens on
its posterior as well as its anterior surface like a
net, called vascular membrane. Usually all these
vessels are absorbed before the birth of the infant,
but if the main branch from the disc to the lens,
or only a portion of it, is absorbed, then the re-
maining portion is seen with the ophthalmoscope
and it usually appears as a dark gray colored
thread or band attached to the disc and stretching
out into the vitreous and moving with the rotation
of the eyeball. There are many variations from
this usual one here described (see pupillary mem-
brane, Fig. 62).
Albinism ( Albinismus) , Albino. This is a
congenital absence of pigment in the choroid and
iris. True albinism is not often seen, and most
cases that are spoken of as albinism have some
slight pigmentation in the iris or iris and choroid.
The pupil appears pinkish in color, as does also the
iris and the eye ground. The choroidal circula-
tion is conspicuous with the ophthalmoscope. The
eyes have very poor vision, glasses are always
necessary, and usually for some form of myopia.
Nystagmus is generally quite conspicuous and the
patient is usually a blonde.
Opaque Nerve Fibers. Medullary sheaths.
The fibers of the nerve usually drop their outer or
medullary sheaths (white matter of Schwann) at
OPAQUE NERVE FIBERS.
the lamina cribrosa. Occasionally in one eye, rarely
in both eyes, some of these sheaths are reinstated
just as the fibers emerge from the disc and are car-
ried into the surrounding retina, sometimes and
usually for a short distance only, but in rare in-
stances for a considerable distance. These opaque
fibers, a congenital condition, are usually seen at
the upper edge of the disc (Plate IX.), or at the
lower edge, or at both the upper and lower edges.
They are seldom seen at the inner or nasal side,
and some authorities state that they are never seen
at the temporal side. In appearance these medul-
lary fibers are glistening white, sometimes bluish
white in color and have feathered or striated edges.
The retinal vessels may be hidden in these fibers
and reappear beyond and also on the disc. The be-
ginner should not mistake these fibers for the snow
bank of Bright's disease (Plate IV.). These med-
ullary fibers may be quite extensive, or few in
number. As they never appear at the macula, cen-
tral vision is unimpaired by them, though the nor-
mal blind spot may be enlarged by their presence.
Connective Tissue. This is occasionally seen to
obscure the disc in part or it may obscure a vessel
or part of a vessel on the disc. This tissue resem-
bles cotton or wool, it is never very extensive, it
is usually congenital, and, like medullary sheaths,
does no harm in the healthy eye. It might act in-
juriously if papillitis should development in such
an eye.
CHAPTER IV.
THE NORMAL EYE GROUND.
As it is necessary for the beginner in ophthal-
moscopy to get a clear understanding and picture
of the interior of a healthy or standard eye 1 before
studying the pathologic or sick eye, it is the pur-
pose of the writer to describe this condition mi-
nutely and carefully, so that after this has once
been mastered, the student will be in a position to
appreciate any change or changes or departures
from the standard condition.
The Normal Eye Ground. The inner surface
of the posterior two-thirds of the eye is commonly
spoken of as the " fundus," from the Latin mean-
ing " bottom," but the term " eye ground " is ap-
plied to the entire inner surface of the eye extend-
ing well forward to the ciliary processes. The
objective points in the eye ground will be described
individually and with the idea of systematizing the
study.
Color of the Eye Ground. Primarily this is
due to the red reflex from the choroidal coat, which
by virtue of its extensive blood supply and pig-
" Five-sixths of the art of ophthalmoscopy are contained in a
knowledge of the normal eye, the rest is a series of representations
which can be read almost at sight." Edward G. Loring, 1886.
108
COLOR OF EYE GROUND. 109
mentation enters more extensively into the pro-
duction of the color of the eye ground, the reflex
and the ophthalmoscopic picture than any other
structure. But there is nothing uniform about
the " reflex," or color, of the interior of the eye,
in fact it has already been stated that the color of
the " reflex " is controlled by the clearness or trans-
parency of the media, by the refractive condition,
the amount of pigment in the tissues, and by the
size of the pupil. The eye of the albino would
give a pink glow to the eye ground, whereas the
mulatto or dark-haired individual would very likely
have a very dark-colored fundus. The eye ground
is not colored uniformly throughout, and many
eye grounds appear much lighter in color as the
periphery is approached; this is due to an unequal
distribution of pigment. Speaking generally, the
color effect of the eye ground is spoken of as
" orange red " in most eyes, and this seems a fair
description, but this color effect may be altered or
appear to change in intensity by the character or
kind of light reflected into the eye. The indirect
method gives a much darker red effect than the
direct method. With these statements about the
color of the eye ground, it is the sincere hope of the
writer that the student who looks into a healthy
eye for the first time, will not feel disappointed be-
cause he does not obtain the same color effect that
has been impressed upon his mind or brain by
studying a certain colored picture in an atlas.
I IO
THE OPHTHALMOSCOPE.
Colored pictures of the fundus are good in their
way as far as the execution of the drawing is con-
cerned, and sometimes true as regards the color,
FIG. 64. HEAD OF THE OPTIC NERVE.
A, Ophthalmoscopic view : Somewhat to the inner side of the center
of the papilla the central artery rises from below, and to the temporal
side of it rises the central vein. To the temporal side of the latter
lies the small physiologic excavation with the gray stippling of the
lamina cribrosa. The papilla is encircled by the light scleral ring (be-
tween c and d), and the dark choroidal ring at d. B, Longitudinal sec-
tion through the head of the optic nerve: Magnified 14 X i. The trunk
of the nerve up to the lamina cribrosa has a dark color because it con-
sists of medullated nerve-fibers, n, which have been stained black by
Weigert's method. The clear interspaces, se, separating them, corre-
spond to the septa composed of connective tissue. The nerve-trunk is
enveloped by the sheath of pia mater, p, the arachnoid sheath, ar, and
the sheath of dura mater, du. There is a free interspace remaining
between the sheaths, consisting of the subdural space, sd, and the sub-
arachnoid space, sa. Both spaces have a blind ending in the sclera at e.
The sheath of dura mater passes into the external layers, .sa, of the
sclera, the sheath of pia mater into the internal layers, si, which latter
extend as the lamina cribrosa transversely across the course of the optic
THE OPTIC NERVE. I I I
but when the color effect is carefully studied it
will soon become apparent that many such pic-
tures are very erroneous and grossly misleading.
It goes without saying that faulty impressions
gained from a poorly colored picture, will give a
healthy fundus the appearance of being hopelessly
pathologic by comparison. No illustration, how-
ever exact it may be, can ever compete with the
actual picture as viewed with the ophthalmoscope.
The Optic Nerve. Also called the disc (some-
times " disk "), or nerve head, or papilla, or intra-
ocular end of the optic nerve (Fig. 64 and Plate
I.). The normal and real size of the disc macro-
scopically is 1.5 millimeters, and its position in the
fundus is about icf_or_i2 to the inner side of the
posterior pole of the eye. It corresponds to what
is known as the normal blind spot in the field of
vision. As the retina has been described as the
optic nerve unfolded, the optic disc may then be
nerve. The nerve is represented in front of the lamina as of light
color, because here it consists of non-medullated and hence transparent
nerve-fibers. The optic nerve spreads out upon the retina, r, in such a
way that in its center there is produced a funnel-shaped depression, the
vascular funnel, b, on whose inner wall the central artery, a, and the
central vein, v, ascend. The choroid, ch, shows a transverse section of
its numerous blood-vessels, and toward the retina a dark line, the pig-
ment epithelium ; next the margin of the foramen for the optic nerve,
and corresponding to the situation of the choroidal ring, the choroid
is more darkly pigmented. ci is a posterior short ciliary artery which
reaches the choroid through the sclera. Between the edge of the chor-
oid, d, and the margin of the head of the optic nerve, c. there is a nar-
row interspace in which the sclera lies exposed, and which corresponds
to the scleral ring visible by the ophthalmoscope. (Description and
figure from Fucks.)
112 THE OPHTHALMOSCOPE.
described as the part of the nerve where the un-
folding begins to take place. The disc is the first
and chief landmark in the study of the eye ground,
and most descriptions and examinations of the
eye ground have the disc as the central point of
departure.
For purposes of study, the disc (see Plate I.) in
most eyes may be conveniently divided into three
parts :
1. The central portion, which is usually quite
light in color, contains the central vessels with
the porus opticus (if present), the physiologic cup
(if present), and a part of the membrana cribrosa
(if present). Any one, or any two, or all three of
these conditions may be seen in a single disc, or
they may all be absent.
2. The margin, one or two millimeters in width,
represents the demarkation from the surrounding
fundus. This margin is whitish or of a pale yellow
color.
3. The space between the margin and the center
is the intermediate zone, and it is this zone that
gives the disc its true color and should have careful
and minute consideration at all times as bearing
upon an intimate knowledge of the normal and the
pathologic, i. e,, atrophy and hyperemia, etc. In
health this intermediate zone is considered to be
pink or yellowish red in color.
Shape of the Disc. This varies; it may be
round, oval or irregular in outline. Usually it
PHYSIOLOGIC CUP. 113
appears vertically oval. The oval shape is usually
explained by a refractive error, astigmatism. The
irregular shape may be explained by some irregu-
larity in the refractive media, or it may be a con-
genital condition. The disc margin in health is
usually quite distinct and easily recognized.
Porus Opticus. The retinal artery and vein as
they pass through the axis of the optic nerve are
covered by a layer of connective tissue called a
canal, and at the disc this canal is occasionally
expanded so that the observer can see down into
it; this is called the porus opticus. If this canal
is not expanded and the vessels bend sharply as
they enter the retina, then there is no porus opti-
cus present.
Physiologic Cup. At or near the center of the
disc (never occupying the entire disc) is often seen
in health a depression or pit; this is called a cup,
and being normal is called physiologic, in other
words the " physiologic cup." It is made by the
separation of the nerve fibers after passing
through the lamina cribrosa. This is in contra-
distinction to another depression to be described
later, and known as the glaucoma cup, which oc-
cupies the entire disc (Plate XII.), and this again
L distinguished from another very shallow de-
pression called a saucer depression, not a cup-
ping. This is seen in optic atrophy, also to be
differentiated elsewhere (Plate X.). This physi-
ologic cupping may be shallow (Plate I.) or quite
ii
114 THE OPHTHALMOSCOPE.
deep; it may have shelving or abrupt edges, or it
may be funnel-shaped or conical, or the nasal side
may be abrupt or steep and the temporal side shelv-
ing gradually toward the edge of the disc; this
latter is quite a common variety. The diameter
of the physiologic cup varies in different eyes; it
may be one-fourth or one-third or half the size of
the disc. Therefore, it may be said that the physi-
ologic cup is not uniform in all eyes or in the same
pair of eyes, and in fact it may not be present at
all, or it may be seen in one eye and not in the other
eye of the same patient. The vessels on the disc
naturally keep close to the disc and therefore fol-
low its surface, and if cupping is present the ves-
sels naturally curve over its edges and are seen at
the bottom of the cup. The color of the cup is
usually white, and at times, by a certain reflection
of the light, may appear glistening, and it is cer-
tainly much lighter in color than the remaining
portion of the nerve. The depth of the cup may be
estimated by the difference in the strength of the
lens used in the ophthalmoscope to see the edge of
the cup, and the other lens required to see the bot-
tom of the cup, or the difference in the strength of
the lens used to focus a vessel at the edge of the
cup, and the strength of the other lens required to
focus the same vessel at the bottom of the cup. The
difference in level between the bottom of the cup
and the prevailing eye ground can be easily demon-
strated by what is called the garallax. To do this
MEMBRANA CRIBROSA. 115
with the direct method, the observer watching the
bottom of the cup and then moving his head per-
pendicular to the line of sight, the edge of the cup-
ping with the surrounding eye ground will appear
to move in the opposite direction. The bottom of
the cup will appear to move with the movement
of his head. Remembering that every three diop- \
ters represent about one millimeter in depth, then i
if the edge of the cup is seen without any lens and
the bottom of the cup is seen with minus three, the
depth of that cup is about one millimeter ; or if the
edge of the cup is seen with a plus six and the
bottom of the cup is seen without any lens at the
sight-hole of the ophthalmoscope, this would make
a difference of six diopters, and the depth of the
cup would therefore be approximately two milli-
meters.
The Membrana Cribrosa (Plates VI. and X.).
At the bottom of the cupping or at a corresponding
point on the disc, if there should not happen to be
any cupping present, there is frequently seen a
gray stippling, or an area composed of little gray
spots with white interspaces; these spots represent
openings in the sclerotic coat for the passage of
the transparent optic nerve fibers. The gray spots
represent the nerve fibers and the white network is
the lamina cribrosa or scleral tissue extending
across the space through which the nerve fibers
enter.
The Scleral Ring (Fig. 64). As the transpa-
Il6 THE OPHTHALMOSCOPE.
rent nerve fibers pass from the disc into the retina
they pass over or through the foramen choroid
and if this opening is large and its edges equi-
distant from the entering fibers, naturally the
white sclera will appear through the transparent
fibers, giving the disc the appearance of being sur-
rounded by a light-colored ring. This according
to Fuchs and others is known as the scleral ring.
Occasionally the foramen choroid approximates
the nerve fibers on one side and this leaves the
sclera exposed through the nerve fibers on the
opposite edge, giving the sclera the appearance of
a crescent (Plate XL). This crescent is usually
at the temporal side. If the choroidal foramen is
small and approximates the nerve fibers on all
sides, then the scleral ring or crescent will be
absent. In myopic eyes and eyes with glaucoma
there is frequently seen at the temporal edge of
the disc a white crescent or this crescent may con-
tinue completely around, forming a ring; this is
due to the absorption of pigment and the scleral
tissue appears through the transparent retina. Ac-
cording to Jaeger this is not a scleral ring, but con-
nective tissue.
The Choroidal Ring. This may or may not be
present (Plate I.), or may appear as a crescent;
choroidal crescent. It usually contains in its com-
position a great deal of pigment and this pigment
may be very irregular or possibly there may
be just one large mass of pigment on one side of
PLATE I.
NORMAL FUNDUS OF LEFT EYE OF A HEALTHY LAD.
J. M. T. Aged 10 years.
History. A blonde with light hair and pink complexion. Blue
irises. Direct method. Refraction almost emmetropic (+0.50 D.).
Disc is round, having light-colored center, distinct margins and
yellowish-red intermediate zone. Choroidal ring almost complete
and slightly more pigmented to the temporal side. Two cilio-retinal
vessels on the lower outer edge of disc passing toward the macula.
The crescentic fovea centralis, with surrounding blood-red area, is
unusually well shown and most typical at this young age. Veins
and arteries are slightly to the nasal side of the disc. The arteries
cross the veins on the disc, but in the periphery the veins cross the
arteries.
118
PLATE I
Normal Fundus
COLOR OF OPTIC DISC. 121
the disc; usually this is not pathologic. The cho-
roidal ring or crescent may be present with a
scleral ring or crescent, or it may be absent in one
or both eyes.
Color of the Optic Disc. This has been de-
scribed as resembling in color the marrow of a
healthy bone, or the " pink " of a sea shell, etc., but
this is not by any means a description that will
answer in every case, as the apparent color of the
disc is controlled in great part in health by the
surrounding eye ground, whether this is heavily
pigmented, as in the mulatto, or but slightly so, as
in the blonde, or whether there is an absence of pig-
ment, as in the albino, or whether there is a physi-
ologic cupping. The student should be ready to
make allowances for these contrasts. In health it
is the minute capillaries in the intermediate zone
together with connective tissue and nerve fibers
which give the disc its " pink " color or " orange
red " or yellowish cast. These minute capillaries
cannot be seen with the ophthalmoscope. Gener-
ally speaking, the disc is pale toward the temporal
side and at the center, while the nasal side is darker.
Plate I. furnishes a good illustration of a normal
disc in its coloring and shape, etc. The reader
should observe this and the other colored plates by
artificial light and not by day light, otherwise he
will be liable to get a faulty color impression.
The vessels seen on the disc (called central ves-
sels) soon branch and rebranch in the nerve fiber
122 THE OPHTHALMOSCOPE.
layers, carrying the blood to and from the retina,
but they are not all of the same calibre nor do they
have the same curves or branches or twinings in
all eyes, or in the same pair of eyes. The central
retinal artery, a branch of the ophthalmic, enters
the optic nerve 10 or 20 millimeters back of the
eyeball and passes forward in the axis of the nerve
and may appear upon the disc as a single vessel,
or if it has branched in the nerve it will then ap-
pear as two vessels, and usually at the nasal side of
the center of the disc. Approximating the central
artery on its temporal side is the retinal vein which
may also be double; it accompanies the retinal
artery in the axis of the optic nerve and empties
into the superior ophthalmic vein or directly into
the cavernous sinus.
Size of the Vessels. The relative normal pro-
portion in size between arteries and veins is gen-
erally recognized as about two to three. The veins
are usually recognized by their larger size and
darker color. The arteries are lighter in color and
like the veins on and near the disc have a light
streak along their centers ; this is due to the reflec-
tion from the coat of the vessel. (Some authori-
ties state that this light streak is due to reflection
from the blood stream for the reason that if the
blood stream is cut off the vessel wall cannot be
seen.) This light streak (reflex streak) has the
effect or appearance of dividing the vessel into two
red lines. The veins being larger than the arteries
SUMMARIZED DIFFERENCE. 123
and their walls not being so tense do not always
have the light streak so conspicuous. The small
arteries and veins do not have the light streak, and
therefore when looking at a small vessel in the
periphery of the eye ground the observer cannot
tell positively whether it is a vein or an artery un-
til he traces it toward the disc. The retinal vessels
do not anastomose.
Summarized Difference between Arteries and
Veins, i. e.,
Arteries. Veins.
Bright red. Dull red.
Smaller. Larger.
Light streak well marked, and Light streak not always so
continues some distance along marked, except on and close to
the vessel. the disc.
Course is usually straight. Course is sinuous and may be
tortuous.
Pulsation seldom seen, except in Pulsation not unusual on disc.
disease.
Usually cross over veins. Usually cross under arteries.
It is interesting to note that in health the arteries
cannot be seen to pulsate, but that in some eyes,
venous pulsation (physiologic) may be seen to
take place in one or more of the large veins on or
near the disc. The explanation of the venous pul-
sation is by the systole of the heart filling the
arteries and making pressure on the vitreous, and
it is this interrupted pressure upon the vitreous that
momentarily compresses the vein on the disc; in
other words, the venous blood has apparently been
forced out of the vein until after the systole of the
heart when it refills, and this gives it the apparent
12
124 THE OPHTHALMOSCOPE.
pulsation. This condition is not present in all eyes,
and when seen does not necessarily mean disease.
This pulsation can be produced and observed by
making considerable pressure with the finger on the
globe of the eye that is being examined. An
anomalous artery of medium size is occasionally
seen to curve over from the temporal edge of the
disc and to pass toward the macula (Plate I.) ; oc-
casionally more than one vessel is seen. This ves-
sel has no connection with the blood supply above
described, but is one of the ciliary vessels, and since
it has appeared in the retina is called a cilio-retinal
vessel. In embolism, etc., this vessel may occa-
sionally be of great value to a patient in preserving
some useful vision. The retinal arteries and veins
while possessing many anomalies, and occasionally
a retinal artery and vein may be seen to twine
around each other, yet they pursue a sufficiently
regular course up and down from the disc to be
named accordingly, i. e., upper nasal artery and
vein, upper temporal artery and vein, lower nasal
artery and vein, lower temporal artery and vein.
Arteries are seen to cross veins, and veins to cross
arteries, but veins are seldom seen to cross veins,
and it is denied that arteries ever cross arteries.
The Retina. As the fibers in the optic nerve,
together with the connective tissue which make up
the major portion of the retina, are transparent,
the retina (anterior to its epithelial layer) is in
health said to be invisible, but this is not altogether
THE RETINA. 125
true, for under certain conditions of light and po-
sition of the fundus at an angle, the retina may be
recognized as a thin gauze or veil, and at times in
young subjects (not in the aged) during the act of
accommodation light streaks resembling the waves
or sheen of a piece of silk may be seen to pass over
the retina, called shot silk retina. The retinal
vessels occupying the nerve fiber layers mark the
location of the retina. These vessels, especially on
and about the disc, appear to be slightly elevated,
and in the general eye ground appear to be lying
well in front of the choroid and not directly upon
it. In young subjects the observer will at times see
a circle about the macula; this indicates accommo-
dative effort and is not a sign of disease. In some
eyes (usually myopic) the observer may occasion-
ally recognize a crescent-shaped reflex at the nasal
side of the disc; this is called the "Weiss reflex,"
and some authorities claim that it is indicative of
progressing myopia.
Macula Lutea. The position of the macula lutea
in the fundus is about two discs in diameter to the
temporal side of the disc and slightly below the
horizontal meridian, it is slightly larger than the
disc. The macula is recognized as being oval in
shape with its long diameter horizontally, it is
darker in color than the rest of the fundus and its
edges gradually shade into the color of the eye
ground. At the center of the macula lutea is the
fovea centralis (center of sight, "fundus f ovea "
126 THE OPHTHALMOSCOPE.
or fovea) ; this is a depression, and its edges give
a reflex. It is very small and appears as a bright
spot one or two millimeters in diameter. In many
eyes it appears as a tiny crescent (Plate I.). It is
rather lighter in color than the surrounding eye
ground. The macular region is that portion of the
eye ground immediately surrounding the fovea cen-
tralis. The macular region contains minute capil-
laries, but it is impossible in healthy eyes to recog-
nize them with the ophthalmoscope. The beginner
with the ophthalmoscope always has difficulty
in seeing and studying the macula unless a mydri-
atic has been instilled, for immediately that the
bright light falls on this extremely sensitive por-
tion of the fundus the iris contracts and the pupil
gets so small that it is almost impossible to see
into the eye, and with this small pupil comes the
corneal reflex, which adds to the difficulty of seeing
the fundus. The macula can best be studied in
subjects less than twenty years of age. In old
people the macula is not so conspicuous. For the
observer to study the macula, the pupil should be
dilated and the patient told to look into the mirror.
The Choroid. This structure is distinguished
principally by the character of its circulation; the
vessels (veins and arteries) all appear alike, they
are large, numerous and flattened, and each variety
anastomoses freely, and they are without the light
streak. Pigment areas between the vessels are also
distinctive of this tunic (albinos excepted). The
THE CHOROID. 127
retinal vessels always appear in front of the cho-
roidal vessels. The choroidal circulation is best
studied in the blonde or albino, and especially in
the latter where the normal pigment between the
choroid and retina is absent, and the vessels appear
red on a white background. In some instances,
however, the choroidal circulation becomes so con-
spicuous that at times it is difficult to study the
retinal circulation (Plate VII.). In other in-
stances the dark pigmentation of the choroid is
quite conspicuous, with the characteristic choroidal
vessels giving it a striped or tesselated appearance,
called " choroide tigree." The choroidal circula-
tion may be seen in many eyes toward the periphery
of the eye ground. In many healthy eyes the cho-
roidal circulation cannot be seen, except a small
portion well forward toward the ora serrata.
Differential Diagnosis between Retinal and
Choroidal Vessels.
Choroidal Vessels. Retinal Vessels.
More numerous. Not so numerous.
Larger size. Smaller size.
Close together. Separated.
Nearly parallel. Divergent as they go toward the
periphery.
Frequently anastomose. Do not anastomose.
Do not diminish in size at Diminish in size at periphery.
periphery.
Veins and arteries not distin- Veins and arteries distinguish-
guishable. able.
Central light streak absent. Central light streak present.
Flat or riband-like appearance. Cylindrical form.
CHAPTER V.
STRUCTURAL ALTERATIONS OR CHANGES IN THE CORNEA,
AQUEOUS HUMOR, IRIS, LENS AND VITREOUS HUMOR
WHICH ARE INDICATIVE OF DISEASE OR INJURY.
The Cornea. Examining the cornea by the
oblique illumination it will always, even in health,
have more or less of a faint smoky appearance,
whereas by ordinary daylight it appears as highly
polished and perfectly transparent. This smoky
appearance does not mean a want of transparency
but* is due to its anatomic construction of lamellae,
etc., see description, Chapter III. This haze, or
smoky appearance, varies with age, is less conspic-
uous in infancy and becomes more conspicuous in
the aged. At any age it may be made conspicuous
by having the light strike the cornea very obliquely.
By means of the oblique illumination one may de-
tect foreign substances which have lodged in or
upon the cornea, such as particles of dust, ashes,
cinders, wood, glass, iron and steel filings, emery,
powder grains, etc. Opacities on the under sur-
face of the cornea, in the disease known as " Des-
cemetitis " (" aquo-capsulitis " or " serous iritis ")
may also be recognized, and ulcers, wounds, phlyc-
tenules, blood vessels, as in pannus, and vascular
keratitis, opaque spots (opacities) in the .cornea
proper, arcus senilis, general loss of transparency
128
THE CORNEA. I 29
in various forms of keratitis, especially the spe-
cific varieties, and also the haziness accompanying
glaucoma, may also be recognized if present.
Corneal scars, or opacities, are described accord-
ing to their size and density. A very faint haziness
of the corneal surface, affecting a part or the en-
tire cornea, is spoken of as a nubecula, meaning
" a mist," and may be compared to the appearance
of a clear glass just faintly breathed upon, or to
an atmosphere faintly foggy. A nebula is a cloud,
and therefore, represents a somewhat greater
density than a nubecula. A nebula may also affect
any part or the entire cornea. A macula is a spot
usually quite white in color but small in size, the
size of a pin head, for instance. Leucoma means a
milk white area, and is usually quite large and may
be spoken of as a large macula; such an opacity
can be seen at quite a distance from the eye and
without the necessity of employing oblique light
and condensing lens to see it. By the laity this
form of corneal opacity is often erroneously called
a cataract. An adherent leucoma is a leucoma hav-
ing some iris tissue bound to it, the result usually of
a perforating wound of the cornea (an ulcer) or an
injury whereby the iris has become entangled in
the wound. Corneal opacities may frequently be
seen with a dimly reflected light, and this is ob-
tained by having the gas flame further removed
from the mirror of the ophthalmoscope than for
the regular distance when examining the interior
I3O THE OPHTHALMOSCOPE.
of the eye. If a foreign substance on, or an opacity
in, the cornea is recognized, its size, shape and loca-
tion should be carefully noted, and for this pur-
pose the cornea is divided into quadrants by
imaginary lines, so that an opacity or foreign sub-
stance may occupy the upper inner, upper outer,
lower inner, or lower outer, quadrant. The opac-
ity or foreign substance may be said to be at the
pole of the cornea, or just above or below or to the
nasal or temporal side of the pole of the cornea, as
the case may be. It may be described as being in,
or on, the cornea in the center of the pupillary area
or in the upper, or lower, or inner, or outer, portion
of the pupillary area. These minute descriptions
are of great importance to the careful ophthalmol-
ogist, as bearing upon a correct diagnosis and prog-
nosis as regards vision in many injuries and dis-
eases. The nearer the disease or injury is to the
pole of the cornea, the more unfavorable the prog-
nosis for good vision. Opacities or foreign bodies
of the cornea may be mistaken for opacities in a
deeper structure, and it is the duty of the observer
therefore to carefully study their location. Any
want of transparency in any portion of the cornea
that occupies the pupillary area (that portion of the
cornea corresponding to the underlying pupil), may
be diagnosed as in the cornea by having the pa-
tient turn the eye slowly in any given direction,
as the observer keeps the light reflected from the
mirror into the pupil and the opacity or foreign
AQUEOUS HUMOR. 131
|
substance will move in the same direction in which
the patient turns the eye. An opacity in the pupil
itself, that is, one occupying the plane of the iris,
appears to maintain its relative position no matter
in which direction the patient turns the eye.
Aqueous Humor. This may be turbid or
muddy, the result of inflammatory products thrown
off by an inflammation of the iris or ciliary body,
or both. Blood in the anterior chamber (called
hyphema) or pus or leucocytes (called hypopion)
may also be seen. The iris adhering in any part
of the cornea is called an anterior synechia, and
adhesion of the iris to the anterior capsule of the
lens is called a posterior synechia. Vessels may
be seen on the surface of the cornea, as in pannus
and phlyctenular keratitis, and in the cornea itself
(interstitial keratitis). On the under surface of
the cornea may be seen small, brownish colored
dots (particles of lymph) arranged frequently in
the shape of a pyramid, with the apex upward
toward the pole of the cornea, and the base of the
pyramid downward ; this occurs in the disease known
as Descemetitis. Foreign substances, such as par-
ticles of iron, glass, powder grains, wood, etc., may
lodge in the aqueous. Entozoa have also been seen
in the aqueous.
The Iris. The anatomy of the iris may be
studied with the oblique light and magnifying lens
(Fig. 17), or, if there is inflammation or injury or
a foreign substance present, these may also be seen.
132 THE OPHTHALMOSCOPE.
It will be well for the physician to make himself
thoroughly acquainted with the normal iris by
studying healthy eyes carefully with the oblique
light, and thus prepare himself for the prompt de-
tection of any departures from the normal, such as
unusual irregularities or growths, gummata, cysts,
tubercles, interpupillary membrane ( Fig. 62 ) , syne-
chia, causing irregular pupils, displaced pupils, or
polycoria. Inflammation of the iris is indicated by
a roughening of the iris, which gives it a velvety ap-
pearance. The apex of the light cone should be
passed slowly over the pupil and the reaction of the
iris to this stimulation should be carefully noted.
An excellent way to obtain the iris reaction is to
use the 5-volt lamp of the luminous ophthalmoscope
and as the patient fixes the lamp, to suddenly turn
on the electric current.
The Lens. To examine the lens satisfactorily
and as much of it as possible, it is well to have
the pupil wide open and to do this it will be neces-
sary to employ a mydriatic unless otherwise contra-
indicated. The lens has the same smoky appear-
ance as that which characterized the cornea under
examination, and the observer must examine it
carefully not only by the oblique illumination but
by the direct method before hastening to make a
diagnosis of a loss of transparency of this struc-
ture. Changes noted in the lens may be foreign
substances, injuries, anomalies, and any of the
various forms of cataract.
OPACITIES OF THE LENS. 133
Opacities of the Lens and Its Capsule. On
the anterior capsule of the lens in the pupillary
area there is occasionally found one or more pig-
ment spots ; these pigment spots may not have any
particular position and in a few instances they are
seen to resemble a crescent, or they may form a
broken ring at the edge of the iris. These spots
are portions of iris pigment, and the result
usually of a previous inflammation of the iris.
Occasionally there is seen one or more fine mem-
branous brown shreds, passing from an attach-
ment to the anterior capsule of the lens (over the
pupillary edge of the iris) to the outer circle of the
iris; this is called an interpupillary membrane
(Fig. 62). Of course the more abundant these
shreds and the more the anterior pole of the lens
is obscured, the more the vision of the eye is im-
paired. In a study of opacities in the lens sub-
stance or capsules, it must be borne in mind that
with the oblique light the opacities appear more
or less gray in color with surrounding darkness,
whereas when studied with the reflected light from
the ophthalmoscopic mirror, they appear black
with a surrounding fundus reflex.
Anterior Polar Cataract. See Chapter III.
Posterior Polar Cataract. See Chapter III.
Lamellar, or Zonular, Cataract. See Chapter
III.
Nuclear Cataract (No. 4, Fig. 64), is an opacity
of the nucleus or center of the lens.
134 THE OPHTHALMOSCOPE.
Cortical Cataract is the reverse of nuclear,
meaning opacity of the cortical portion of the lens.
This may be more or less complete, but usually it is
more conspicuous in the lower inner quadrant of
the lens, and in any instance it is diagnosed with the
ophthalmoscope by seeing dark spicules or striae
like needles pointing toward the center of the lens.
~This is the most common form of beginning senile
; cataract (No. 4, in Fig. 64). Cataracts are also
; named from their causes.
Choroidal Cataract usually begins as a nuclear
cataract; it is brown in color and is the result of
choroidal disease; from its color and resemblance
to mahogany wood it has been called " mahogany
cataract."
Traumatic Cataract is a cataract caused by
injury.
*In the so-called Black Cataract the lens becomes
quite dark in color from absorption of or staining
by pigment.
Morgagnian Cataract is an over-ripe cataract.
The cortical substance has become fluid and the
nucleus remains hard and drops to the lower por-
tion of the lens capsule, which now resembles a
bag containing a milky fluid. The iris often ap-
pears tremulous.
Senile Cataract is the cataract of old age; a
better name would be hard cataract, or an opaque
sclerosed lens. Whenever partial opacity of the
lens is diagnosed it is wise to study the whole lens
SUBLUXATION. 135
carefully, and also the interior of the eye, if the
opacity does not interfere too greatly with a view
of the eye ground, and to do this it will be necessary
to dilate the pupil with a solution of cocain (Chap-
ter I.).
Subluxation or Dislocation of the Lens. If the
ligament of the lens becomes relaxed or broken
partially or completely, the lens will become sub-
luxated or dislocated; in the former instance its
edge may be seen in the pupillary area; if dis-
located by force the lens may pass through
the pupil into the anterior chamber or fall
back into the vitreous. If the lens is in the
anterior chamber it can be easily recognized;
if in the vitreous or absent from the eye, and
the iris is not impaired, then its absence may
be recognized by a tremulousness of the iris
(iridodonesis). The iris having the aqueous in
front and back of it (the lens being out of posi-
tion) it naturally trembles or feels the wave motion \
when the eye is suddenly rotated; this trembling
of the iris is also noted in Morgagnian cataract.
The absence of the lens can usually be diagnosed
by the greater depth of the anterior chamber, and
the tremulous iris and the refractive error, as meas-
ured by the strength of the glass required to see
the fundus. If the lens has been dislocated into the
vitreous it may be studied in its new position with
the ophthalmoscope, if there has not been too much
reaction resulting from irritation caused by the
136 THE OPHTHALMOSCOPE.
lens. Partial dislocation of the lens, which brings
the edge of the lens into the pupillary area, may
be diagnosed by oblique light or with the ophthal-
moscope, the portion of the pupil without any lens
giving a different refractive estimate, when the
fundus is observed than the portion occupied by the
lens (see Ectopia lentis, Chapter III.).
The Vitreous Humor. Changes in the vitreous
indicative of disease, are loss of transparency in
parts (opacities) and diminished consistency.
Opacities of this medium may be from degenera-
tion of the substance itself or from hemorrhages
or exudates thrown off by the choroid or retina
or ciliary body or iris. Opacities of vitreous may
be caused by foreign bodies. Vitreous opacities
are of varying shapes and sizes, and may occupy
any portion of the vitreous. They may appear
black, brown or gray in color, or semi-transparent.
/They are variously described by the patient as
looking like different animals or fishes. They are
also spoken of as " motes " or " gnats in front of
the sight." These opacities may be quite station-
ary or freely mobile, depending greatly upon the
fluidity of the vitreous. Foreign substances, such
as pieces of glass, steel, iron filings or chips of
metal, etc., entering the eye, may carry air into
the vitreous, and this is recognized as bubbles look-
ing not unlike bubbles of air under the cover slide
in the field of the microscope. Foreign substances
reflect light from their edges, while air bubbles
VITREOUS HUMOR.
reflect light from their centers. The path of the
foreign body as it passed through the vitreous is
occasionally recognized as a gray streak.
Opacities and changes in the vitreous may be
studied with the oblique or focal illumination, or
with the light reflected from the mirror at several
inches distant or with the mirror and a lens at the
sight-hole of the ophthalmoscope. It is only in
rare instances that the oblique illumination is used
for studying vitreous changes and the ophthalmo-
scope with a plus lens at the sight-hole is used by
preference. The lens in the ophthalmoscope which
gives a clear view of an opacity in the vitreous, gives
some idea as to its nearness to either the disc or pu-
pil, i. e., if seen with a strong lens, say a + 7 D., the
eye being emmetropic, this would indicate at once
that the opacity was well forward ; if the opacity was
seen with a + I D. it would therefore be well back
near the retina. If the observer is seated ten or
twelve inches from the eye and reflects the light into
it and an opacity is present and recognized, then if
the patient is told to rotate or turn his eye upward,
i the opacity will appear to move downward if the
I opacity is situated back of the plane of the iris,
but if the opacity is in the cornea or aqueous or an-
terior capsule of the lens, then it will appear to
move upward as the eye is turned upward; in
fact, it may be stated as a rule that all opacities
lying in front of the plane of the iris will move in
whatever direction the eye is turned or rotated,
138 THE OPHTHALMOSCOPE.
and those opacities lying back of the plane of the
iris will appear to move in the opposite direction to
that in which the eye is rotated. This statement of
facts applies particularly to eyes with small or un-
dilated pupils, whereas eyes with large pupils give
a slight difference in the appearances, as the ob-
server is then able to see a trifle further back
into the eye and the center of rotation appears
beyond the plane of the iris. The normal center
FIG. 65. To DETERMINE THE POSITION OF A FIXED OPACITY IN THE
EYE. (Jennings.)
In the upper drawing is shown an opacity on the cornea at a, one on
the anterior surface of the lens at b, and one on the posterior surface
at c. Looking into the eye, these three opacities appear as one black
point in the center of the pupil. If the patient is now requested to
look down, three black points appear, c moves upward, b remains sta-
tionary, and a moves downward.
of rotation lies back of the lens about 10 milli-
meters from the disc. However, when the opacity
lies very near the plane of the iris it is apparently
so stationary when the eye is rotated that it is often
necessary to employ the oblique light to make a
CHOLESTERIN CRYSTALS. 139
positive diagnosis of its exact location. Figure 65
explains the description just given. New growths
are occasionally seen in the vitreous, such as cysts,
proliferations from the retina (retinitis prolifer-
ans) and also entozoa, the cysticercus cellulosae and
filaria. These latter have been seen in the cornea,
iris and lens, but their most common location is
between the choroid and retina.
Foreign bodies in the vitreous may be recog-
nized if seen quite early, but after a few hours the
vitreous surrounding them usually becomes more
or less cloudy. Vitreous opacities when they move
freely by slight rotation of the eye, become very
annoying to some patients, and at times cause hal-
lucinations.
Cholesterin Crystals (synchysis scintillans,
sparkling synchysis; synchysis etincelant) are seen
at times in the vitreous humor, and give a most
beautiful pyrotechnic display when seen with the
ophthalmoscope. Each crystal reflects the light,
giving the appearance of a shower of gold. It is a
rare condition before the age of fifty. There is
no cure for this condition. It may appear in one
eye alone or in both.
CHAPTER VI.
VISUAL ACUITY. FIELD OF VISION. PERIMETRY.
IN connection with the ophthalmoscopic findings
of pathologic changes, the physician should be
ready to make a record of the visual acuity and the
field of vision of each eye, as these two records will
often aid him materially in a correct diagnosis and
prognosis.
Visual Acuity. This is generally understood
and spoken of as central or direct vision, and
the part of the retina
concerned is the fovea
centralis. When an
eye looks at an ob-
ject and the image is
formed at the fovea
centralis, the eye is
said to " fix " the ob-
ject. Visuaf acuity may
be defined as the see-
ing quality of the eye
without glasses. The
standard visual acuity is
the power of the eye to
distinguish letters and characters occupying an
angle of five minutes. Such letters and characters
140
c
E
C P
C P
in
A L
tn
L A
G Y"D T
V F H U A
T G~Y D
F A V H U
L E C H D O
CEO R~L C P A
D L O E C N
C P A R'C E O L
FIG. 66. Randall's Test-letters.
Block letters on black or cream-
colored cards.
VISUAL ACUITY.
141
in black are engraved on a cream-colored card, or
white letters on a black card are shown in Figs. 66,
67, 68. These cards uniformly illuminated are
placed 20 feet (six meters) from the patient and
each eye 'is tested separately by covering its fel-
low. The patient pronounces __
the letters or if illiterate he
tells the direction in which the
arms of the E are pointed.
f The lowest line of letters or
characters which the eye can
recognize distinctly, is the vis-
ual acuity of that eye and it is
recorded in the form of a frac-
tion, the numerator of the
fraction being the distance
of the eye from the card and
the denominator being the size
of the letters distinguished.
For the guidance of the
physician each line of letters
or characters, is marked in
small roman characters which
tell him at once the dis-
tance (in feet or meters) at which such letters or
characters should be read by the standard or emme-
tropic eye. The standard visual acuity would be
the line of letters marked 20 feet or 6 meters
which should be read with ease at the distance of
20 feet. If the eye cannot see or recognize the
FIG. 67. Gould's Test-
^ Goth h j c [ etters H in
white on a black card.
III
142 THE OPHTHALMOSCOPE.
top letter on the test card at the distance of 20
feet, then the distance must be shortened by bring-
ing the card slowly toward the patient or letting
the patient approach the card un-
B I til he is able to recognize the letter
S j>L 1 distinctly.
Peripheral Vision. This is
known and spoken of as indirect
vision or the visual field, and the
part or parts of the retina con-
^~ III H
& *** l3 cerned lie more or less remote
E 3 UJ n from the fovea centralis. The
fovea centralis represents the
u 3 E m m
most acute vision and peripheral
u m E u 3 E
or indirect vision is much less
FIG. 68. illiterate acute and therefore not so easily
Card. obtained as the direct. Indirect
vision diminishes or becomes much
more indistinct as the outermost limits of the retina
are brought into use.
To Test Peripheral or Indirect Vision. Each
eye must be examined separately as in testing cen-
tral or direct vision, i. e., keeping the eye covered
which is not being tested. Testing peripheral
vision is known as perimetry, and an instrument
known as the perimeter is generally employed for
exact work (Fig. 69). With this instrument on
a convenient table and the patient comfortably
seated, his chin is placed on a rest and the eye to
be tested is opposite to, and 13 inches from, a round
PERIPHERAL VISION.
white disc 10 millimeters in diameter, fixed in the
center of a semicircle. As the eye fixes the disc
the physician at the back of the perimeter watches
the patient's eye that it remains fixed during each
step of the examination. Then with either of his
FIG. 69. McHardy's Perimeter.
hands the physician revolves the milled wheel at
the back of the semicircle and thereby a carrier is
made to travel along the inner side of the semi-
circle by means of pulley and cord. This carrier
contains a disc with various colors upon it and any
one of these colors may be exposed to most any
convenient size as the physician may select. A
field chart or blank (Fig. 70) is placed in the
bracket attached to the back of the perimeter.
There is a small steel needle at the back of the
semicircle near the milled wheel. The semicircle
144
THE OPHTHALMOSCOPE.
will take any meridian in which the physician
wished to place it by merely pressing it with his
hand. The inner surface of the semicircle should
always be uniformly illuminated. The physician
usually places the carrier with its selected color one
centimeter in size, at the extreme end of the semi-
FIG. 70. Field charts for Right and Left Eye.
circle and gradually brings it toward the center on
which the patient is fixing. As the carrier with
its .exposed color is brought toward the center (by
the physician turning the milled wheel) the patient
is instructed to tell as soon as the peripheral object
comes into view. When this is mentioned the phy-
sician stops turning the wheel and presses the
chart against the steel needle, which makes a punc-
ture at a point in the chart corresponding to the de-
gree mark on the semicircle. In this way the various
meridians are recorded on the chart. Usually they
PERIPHERAL VISION. 145
are 15 degrees apart, though they may be made closer
if desired. After the meridians have been recorded
the physician connects the individual points with
straight lines, using pencil or pen, and these con-
nected points represent the outermost limit of
vision. The record is made in the same way for
the various colors. That for white is spoken of
as the form field.
The peripheral field is naturally reduced in the
direction of the overhanging brow and in the di-
rection of the nose, and therefore it is not so re-
stricted downward and outward.
If a perimeter is not at hand for recording
peripheral vision the record may be made upon a
blackboard, but it must be remembered that the
record thus obtained upon a plane surface is quite
different from the perimetric findings. An ex-
cellent method and one always at hand for making
an approximate test, is for the physician to sit
facing the patient so that their eyes are about 26
inches apart. The patient closes the eye not being
tested and the physician closes his eye that is di-
rectly opposite to the one the patient closes, or the
physician keeps his right eye open when testing the
patient's left eye, and vice versa. In this position
with the eye of the physician and patient fixing
each the other, the physician uses the end of a black
lead pencil or a black pen holder as a finder, the end
of the finder having a small piece of white paper a
quarter of an inch wide wrapped around it. The
146 THE OPHTHALMOSCOPE.
physician moves this finder inward from arm's
length midway between his and the patient's eye.
The physician's peripheral vision being normal, he
will know at once when the patient's eye should
recognize the white paper. Colored papers may be
used in the same way. The end of the handle of
the Morton ophthalmoscope is adapted admirably
for this purpose. The field of vision taken in
this way is not exact, neither can it be exactly re-
corded, but it is often most suggestive and of great
value, until a careful perimetric tracing can be made
later. The normal peripheral field, while of the
same outline as the chart, is not the same size for all
colors; that for white (or form) is the outermost
and largest, then comes blue, then red and then
green. The field of vision may also be taken with
two lighted candles in a dark room. One candle is
held in front of the eye, and the other candle is car-
ried through the various meridians. This is known
as the candle field. This is not exact. It is merely
suggestive.
Scotoma (O-KOTO?, darkness). The one spot in
the field of vision which does not see and is therefore
normally blind, is called the physiologic blind spot,
or Mariotte's blind spot, and is situated about i_
degrees to the outside of the point of fixation (o
in Fig. 70), this corresponds to the entrance of the
optic nerve. Scotomata are recognized when the
field of vision contains areas or spaces which are
defective in their normal seeing quality or con-
SCOTOMA. 147
tracted or distorted in outline by certain diseases of
the eye itself and also by various general diseases.
Concentric contraction of the field of vision is a
form of scotoma, in which peripheral vision is re-
duced in size in all meridians, depending upon the
stage of the disease in which this condition is
found.
The size of the normal field is shown in Fig. 70.
The field of vision may be cut off in quadrants or
sectors or halves ; this latter is spoken of as " hemi-
anopic " or half field. In making the test for
scotoma the test object must be quite small, 2 to 4
millimeters in size.
Central Scotoma. This indicates the loss of
good central vision, it may be partial or complete,
and is found in macular diseases from syphilis,
myopia, and from toxic amblyopia, etc. Scotomata
are also classed as paracentral, peripheral and ring.
A scotoma is said to be positive when the patient
is conscious of a dark area in his field. A scotoma
is said to be negative when the patient has a sco-
toma and is not conscious of its presence. A nega-
tive scotoma may be absolute or relative, the for-
mer when white and colors cannot be recognized
and the latter (relative) when the light sense is
diminished. Frequent reference to visual acuity
and the field of vision will be made in the considera-
tion of ophthalmoscopy.
CHAPTER VII.
RETINAL VESSELS. HEMORRHAGES. PIGMENT CHANGES.
HYPEREMIA. ANEMIA. EMBOLISM. THROMBOSIS.
The Retinal Vessels. Pressure upon the nor-
mal eyeball with the end of the finger, while the
observer views the retinal vessels, will show an
impediment to the blood current entering and leav-
ing the eye and with the result that the blood is
held in the retinal vessels. Great pressure, if the
subject will tolerate it, shows an entire emptying
of the vessels on the disc. The light streak in the
vessels is consistently diminished or absent, accord-
ing to the amount of pressure, and the length of
time the pressure is maintained. Great pressure
may blanch the disc to a distinct whiteness from
its normal color. The statement that the nor-
mal proportion in size between arteries and veins
is as two to three is particularly true of the vessels
in the retina, but it is not true of the vessels on the
disc, which may appear to grow narrow or re-
stricted and quite frequently a vein on the disc may
appear abnormally large. However, any great in-
crease or diminution in the size or breadth of a
vessel or part of a vessel in the eye ground, aside
from the disc is quite indicative of disease; for
instance, arteries and veins may both be increased
148
THE RETINAL VESSELS. 149
in diameter or the arteries may remain normal and
the veins diminish, or, what is much more usual,
the veins may become greatly increased in width.
Changes in the retinal vessels are not always easily
detected unless the condition is well marked or care-
fully loc Jted for, simply because there are normally
many differences, and it is therefore good practice
to compare the size of the vessels in the two eyes.
This careful comparison will at least make a diag-
nosis of a systemic condition, as compared with a
local manifestation. The fact must also be borne in
mind, that there is an occasional exception to this
comparison of relative size between arteries and
veins when there happens to be two veins accom-
panying an artery, or two arteries accompanying
a vein.
Increase in Diameter of Veins. These are usu-
ally seen in inflammation of the retina where the
disc is also involved, and at the same time the
veins may become tortuous, while the arteries are
diminished in size. This increase in the diameter
of the veins may be limited to only a few of the
veins or possibly the increase affects but one vein
or a part of a vein, and is due to an inflammation
involving the vessel walls or to pressure on the
venous trunk in the membrana cribrosa, or after
it leaves the eye, or it may be due to some general
venous congestion. Veins increased in diameter
(beyond the normal size) are seen in specific and
splenic retinitis, and in fact in nearly all varie-
I5O THE OPHTHALMOSCOPE.
ties of retinitis; the early stages of fever, such as
typhoid; also in pleurisy, pneumonia, asthma, and
in congestion and inflammation of the brain or its
meninges; in various forms of heart disease and
anemia. Any impediment to the return blood
stream from the eye will naturally cause the veins
to become distended, and this is seen to be the case
in such diseases of the eye as glaucoma and oplis
nejjritis, and undue pressure on the venous trunk
between the eye and the heart, as in diseases of
the orbit, erysipelas, cellulitis, growths, etc.; and
pressure in the neck from goitre and various
growths ; and in various diseases of the lungs, espe-
cially phthisis.
Decrease in Diameter of the Veins. This con-
dition of the veins is not at all common, and when
seen is usually a condition or disease of the eye
itself, such as atrophy of the retina or optic nerve.
In embolism of the central artery the veins in some
portions are quite narrow. The diameter of the
vein decreases in degeneration of the vessel itself.
Increase in Diameter of the Arteries. This
condition, like diminution in the size of the veins,
is very rare indeed, and when recognized is usu-
ally caused by some disease of the coats of the
artery which has weakened its contractile power,
and yet this condition may be seen when the heart
action is increased; also in early stages of fever,
pneumonia, pleurisy, brain disease and leukemic
retinitis.
DIAMETER OF ARTERIES.
Decrease in the Diameter of the Arteries.
This condition of the arteries is much more com-
mon than an increase in their size. Intra-ocular
pressure which keeps the blood from entering the
eye as freely as it otherwise would, will cause a
diminution in the size of the arteries; therefore, a
decrease in the diameter of the arteries is seen in
glaucoma, embolism, papillitis, thrombosis, hemor-
rhagic retinitis, etc. Optic and retinal atrophy fol-
lowing inflammation leaves the arteries not only di-
minished in calibre but also with a white line seen
in the vessel for a considerable distance from the
disc; this is due to sclerosis of the middle coat of
the artery and this whitening of the coat may be
sufficiently dense to obscure any view of the blood
stream, the artery or arteries looking like white
threads or cords. The arteries are seen to be di-
minished in size in conditions resulting from weak
heart, also anemia and chlorosis, epilepsy, etc. Reti-
nitis pigmentosa causes a diminution in size of
both arteries and veins. A thickening in the
arterial coats and a diminution in the calibre of
the arteries results in albuminunc_retinitis.
Changes in Vessel Walls Arteriosclerosis.
These may be designated as fatty degeneration,
chalky deposits, perivasculitis and sclerosis; the
arteries are unevenly narrowed or the arteries may
be bordered by extravasations, and the veins may
be distended, showing many narrowings or con-
strictions like the arteries. These conditions are
152 THE OPHTHALMOSCOPE.
usually recognized with the ophthalmoscope by
diminution in the normal transparency of the ves-
sel walls. The vessel walls having their lumen di-
minished will naturally reveal this condition, when-
ever there is any crossing over of the vessels as the
blood current is diminished at this crossing, if there
is any pressure exerted, and then the vessel again
refills after the crossing (Plates VI. and X.). One
vessel or a part of a vessel, or all the vessels, may
be affected by these changes. Sclerosis of the
vessels is quite conspicuous in retinitis pig-
mentosa, whether of the congenital or acquired
(specific) variety. Sclerosis of the vessels may be
seen in any form of retinitis, but especially in the
nephritic variety.
Perivasculitis. This is an increase or a hyper-
plasia of the connective tissue about the vessels,
principally and usually the arteries (periarteritis)
(Plate IV.). The condition is recognized with
the ophthalmoscope by the yellowish-white color of
the vessels, which appear in some instances, when
inflammation and proliferation is excessive, to look
like white threads. If the inflammation is not so
severe the sides of the vessels appear to have a
yellowish-white color, or the vessels appear to be
bordered with delicate or narrow white lines, seen
in eyes having post-papillitic atrophy or atrophy of
the retina.
Vessels of New Formation in the Retina.
These are very rare indeed and when present are
RETINITIS PROLIFERANS. 153
seen to run in the same direction usually as the
large vessels; they appear in isolated areas and a
common position is on, or near, the disc. They
maintain about the same caliber throughout, with
very little, if any, diminution in size, and are often
quite tortuous, and on this account have been de-
scribed as " cork screw." Growths in the choroid
and retina may show vessels of new formation.
Vessels of New Formation in the Vitreous
(Retinitis Prolif erans) . Like vessels of new for-
mation in the retina, these form a very rare condi-
tion, and from the same cause presumably, viz.,
some severe inflammation of the retina in which
the connective tissue about the retinal vessels, or
a single retinal vessel, has become vascularized.
During this severe inflammation of the retina no
distinct view of the eye ground can be made out,
but when this inflammation subsides these newly
formed vessels, supported by connective tissue,
may be recognized extending across the fundus
and into the vitreous, resembling bands with many
fine loops of vessels of varying length, and occa-
sionally these vessels appear like strands of rav-
elled thread. Vessels of new formation are ap-
parently venous.
Aneurisms, or Varicosities, or Dilatations of
the Retinal Vessels. These are rare conditions,
and may be congenital or caused by trauma or in-
flammation. A dilation of a retinal vein on the disc
is not uncommon but has erroneously been spoken
154 THE OPHTHALMOSCOPE.
of as an aneurism. An aneurism of a retinal artery
would be recognized by its more or less rounded
shape in the course of the artery, resembling a bead
on a string or thread, the light streak in the vessel
being interrupted at the aneurism.
Arterial Pulsation. This is not a common con-
dition, and when present is usually pathologic; if
seen extending well into the retina beyond the
disc it usually signifies aortic valvular disease (in-
sufficiency). Pulsation of the arteries on the disc
is most commonly seen in glaucoma, a point in diag-
nosis in this disease.
Owing to the position of the retinal vessels be-
tween, the choroid and the vitreous, they naturally
receive pressure from the front, and the back, and
on this account they are found to be oval on sec-
tion, the horizontal diameter being greater than
the perpendicular. If the retinal vessels are dis-
tended they naturally approximate a circular
shape; hence the broader the light streak, the flat-
ter the vessel, and vice versa.
Venous Pulsation. This is not necessarily path-
ologic; on the contrary, it is normal in most cases
when seen upon the disc or extending a short dis-
tance into the retina (see Chapter IV.). It may
be seen with an increase of intra-ocular tension.
Hemorrhages. There is no portion of the
retina which may be considered exempt from the
presence of hemorrhages, and these may occur
in any layer or in any portion of its surface. Hem-
HEMORRHAGES. 156
orrhages from the retinal vessels vary in their
color, shape, size and location. Most hemorrhages
at the time of their occurrence are darker than the
general f undus reflex, being bright red, and later be-
come darker in color, and may disappear by absorp-
tion of the clot, and no evidence of their previous
existence will be recognized; yet occasionally some
pigment may appear after the hemorrhage has been
absorbed, but this is rare. A very profuse hemor-
rhage may leave its mark by the presence of
spots of a brownish or brownish-black color. As
a rupture of a retinal vessel only takes place by
violence, hemorrhages in the retina from disease
must take place by the escape of blood through
the vessel walls. A very natural inference in re-
gard to hemorrhages in the retina, as elsewhere,
would be that they would occur in the periphery of
the eye ground where the vessels are small and pre-
sumably weaker, but while this is undoubtedly good
reasoning, yet the very reverse is the case; the
hemorrhages occurring from the large vessels
whose walls cannot resist the pressure, which pres-
sure is very likely much greater in the large ves-
sels than in the small ones; in other words, the
walls of the smaller vessels must be stronger or the
pressure is less by the time the blood stream gets
to them, or both conditions may exist. With this
understanding of the vessels affected, it will be bet-
ter appreciated why the most common seat of reti-
nal hemorrhages is at the disc and its immediate
15'-> THE OPHTHALMOSCOPE.
neighborhood. The next most common situation
for the presence of retinal hemorrhages is at the
macular region, and naturally hemorrhages at the
macula obscure vision more and more as the fovea
centralis is encroached upon. Hemorrhages in the
periphery are of capillary origin and have this sig-
nificance, that the morbid process is either in the
capillary vessel walls, or if in the large vessels also
it is the small vessels which are mostly affected,
and usually this means a grave general disease and
is much more significant, if the hemorrhages are
in the deep layers of the retina.
Shape, Size and Location. Hemorrhages in
the nerve fiber layer (inner layers) of the retina,
appear more or less streaked, having rather
straight edges or sides, and their ends, especially
the distal ends, resemble the edge of a feather or
gas flame, and are therefore commonly described
as " feathered edged " or " flame-shaped." The
cause of this peculiar striation is that the blood
works its way between the nerve fibers, which ap-
pear to cut it into fine lines (Plates V. and VI.).
Hemorrhages in the deep layers (outer layers) of
the retina are not so characteristically marked but
appear as small red dots, round or irregularly
shaped (Plate VI.). Hemorrhages between the
retina and the choroid may appear round or oval
with sharp cut edges; the retinal vessels may be
seen passing over such hemorrhages, which would
indicate at once that the hemorrhage must be back
HEMORRHAGES. 1 5 7
of the retina, and of course the retina must be more
or less elevated at the location of the hemorrhage.
A hemorrhage between the retina and the vitreous
called a subhyaloid hemorrhage, has a circular
shape and sharp edges, and naturally such a hem-
orrhage obscures any view of the retinal vessel be-
hind it. A subhyaloid hemorrhage may have its
upper edge quite straight and its lower edge a con-
vexity downward ; this is due to the blood settling by
gravity. Retinal hemorrhages may appear isolated
without any apparent connection with vessels, but
usually they lie near the vessels. A retinal hemor-
rhage may be so large that it will break through
the hyaloid membrane and escape into the vitreous,
and in this way it is a frequent cause of vitreous
opacities.
Causes of Retinal Hemorrhages. Retinal
hemorrhages may be caused by over-distension of
the vessel, or degeneration of the vessel wall, by
alteration of the blood itself, and occasionally by
injury; all inflammatory diseases of the retina
itself; increased heart action; abnormal and sud-
den suppression of the menses; diseases of the
brain, kidneys and spleen; diabetes; pernicious
anemia, leukemia; gout; tuberculosis; scrofula;
purpura; hemorrhagic diathesis; degeneration of
vessel walls; thrombosis and embolism; injuries;
etc.
Changes in the Vascularity of the Retina.
These may be many or few; they may be limited
158 THE OPHTHALMOSCOPE.
to several vessels or to a single vessel, or a part
of a vessel. As an extreme condition of pallor or
diminution of the blood supply to the retina, may
be mentioned embolism of the central artery (Plate
II.); and as the extreme condition of engorge-
ment of the retina may be mentioned thrombosis
of the central vein (Plate III.).
Pigment Changes. Normal pigmentation more
or less extensive may be seen at the choroidal ring
in almost every eye (Plate I.) and occasionally an
innocent amount of pigment may be seen in a small
mass at the upper edge of the disc, and not infre-
quently a small round spot of pigment the size of
a pin head, or a trifle larger, may be seen at some
distant point in the retina where it is not of any
serious consequence (Plate VIII.), and yet each
spot of pigment, wherever situated, should have
careful consideration. Scattered areas of pig-
mentation should always be looked upon with sus-
picion, especially those connected with changes in
the choroidal coat (Plate XL) and those seen upon
the retinal vessels.
Hyperemia of the Retina. It is not an easy
matter for the beginner in ophthalmoscopy, to ap-
preciate this characteristic condition of the eye
ground, and yet it is a most important one, and one
often overlooked, if the observer is not extremely
cautious. Overlooked in the sense that it may be
so well marked as to suggest a beginning retinitis
or papillitis; however, the patient's history, etc.,
IIYPEREMIA OF RETINA. 159
will surely put the observer on his guard. Hyper-
emia of the retina is manifest principally upon the
disc and its immediate neighborhood by a conges-
tion of the retinal capillary vessels which lie in the
most anterior layers of the retina, and as these
vessels are not ordinarily prominent in healthy
eyes, their congestion will give the retina a striped
appearance about the nerve, and its edges will be-
come somewhat obscure or " wgolly." The nerve
(intermediate zone) may have a red brick dust
color. The macular region, if carefully observed,
will appear of a much darker hue than is consistent
or in keeping with the general appearance of an
otherwise quiet eye. This hyperemia of the
retina, described by Jaeger as " irritation of the
retina." is the unique picture often seen in eyes
with refractive errors, especially of the hyperopic
(hypermetropic) variety. As nearly 80 per cent.
of all eyes have some form of hyperopia, then,
as just stated, " irritation of the retina " is not such
an uncommon condition, especially if the eyes have
not been " glassed," or if the glasses are not correct.
Retinal irritation as just described is brought
/about therefore by accommodative effort and the
1 condition is recognized as a disease and called ac-
\commodative asthenopia. The symptoms are in
keeping with the irritated and fatigued retina and
ciliary muscle, though the vision is not as much at
variance as might be expected by the refractive er-
ror present; the patient, however, complains of his
l6O THE OPHTHALMOSCOPE.
eyes feeling tired, the eyeballs ache, blurred vision
comes on after prolonged near work, or after a time
this blurred vision may come on promptly after using
the eyes for only a few minutes, while looking atten-
tively at any nearby object. With the blurred vision
there is often a dread of light (photophobia).
Frontal headache (brow ache) over both eyes or
over one more than its fellow, usually over the eye
with the least refractive error. The frontal head-
ache may extend into the temples, a temporal head-
ache, and nausea and dizziness may also be present.
If the patient forcibly concentrates his vision, the
object looked at may soon appear unsteady or in-
distinct, and then the eyes may become suffused with
the lacrimal fluid. The treatment is rest with a
cycloplegic and dark glasses, and carefully selected
glasses, the eyes being made equal to the emmetropic
or standard condition, which is a minimum amount
of accommodative effort for the work at which the
eyes are engaged.
RETINAL IRRITATION, OR HYPEREMIA, FROM EXPOSURE
OF THE EYES TO SUNLIGHT (SOLAR RETINITIS); TO
ELECTRIC LIGHT AND FLASHES OF ELECTRIC LIGHT
(ELECTRIC RETINITIS); TO REFLECTION FROM THE
SNOW (SNOW BLINDNESS).
The symptoms of these conditions are, photo-
phobia and lacrimation with irritation of the con-
junctiva. The patient's history gives the cause.
Sun blindness and snow blindness usually re-
cover after the use of dark glasses for a few days
unless the condition is complicated by conjunc-
ANEMIA OF RETINA. l6l
tivitis and ulcer of the cornea or macular changes,
when appropriate treatment for these compli-
cations must be met. Electric retinitis is a much
more serious matter, for when the exposure has
been a lengthy one, or the electric flash has
been intense, there may be extensive changes
set up in the macula and macular region of a low
grade retino-choroiditis, which may leave per-
manent changes and damage to central vision. The
treatment for such cases is rest of the eyes with
dark glasses and restraint from any use of the eyes
whatever until fully recovered. It may be neces-
sary to institute internal medication, and to use a
solution of atropin in the eyes for a few days. If
snow blindness is complicated with changes in the
macula, then a similar line of treatment must be
carried out.
Anemia of the Retina. This is the reverse of
hyperemia and therefore gives something of a re-
verse picture, and the striations at the disc edges are
absent. The disc is pale and the general fundus re-
flex is lighter in color than normal. The arteries
are not distended, and if compression or embolism
of the central artery is present, the picture of
anemia of the retina is typical (Plate II.). The
ophthalmoscope reveals diminished amount of blood
in retinal vessels by the absence of the light streak,
which, if present at all is very narrow and does not
extend far into the eye ground. The veins and
arteries are equally affected. There are exceptions
1 62 THE OPHTHALMOSCOPE.
to this broad statement and the arteries may be
small and veins large. Naturally the eye ground in
anemia appears paler than normal and the pale
condition is in keeping with the light color of the
disc, so that the line of demarkation between disc
and surrounding eye ground, is not always very
well marked. This condition must not be con-
founded with optic atrophy where the contrast is
very marked, but in the beginning of optic atrophy
the contrast is not so conspicuous. Systemic
anemia from any cause will often express itself in
anemia of the retina, but a pale face does not neces-
sarily mean anemia of the retina, nor does a florid
complexion necessarily mean hyperemia of the
retina. While admitting that a patient's color may
be an index of his blood condition, yet a pale com-
plexion may be due to a want of blood in the capil-
laries of the skin and no change be noted in the
retina, and a florid complexion may mean blood in
the capillaries of the face, and yet the system be
anemic, as indicated by the retina.
Differential Diagnosis, as Revealed with the
Ophthalmoscope between Pallor of the Disc and
Retina in Anemia and that Caused by Optic
Atrophy.
Anemia. Atrophy (Plate X.).
Pallor of disc. White disc.
Surrounding eye ground also Surrounding eye ground appears
pale. redder than normal.
PLATE II.
EMBOLISM OF THE CENTRAL ARTERY OF THE LEFT EYE. DIRECT
METHOD.
S. B. Male. Aged 61 years.
History. Embolism came without any warning in a man other-
wise apparently well. (Two years later, without apparent cause, a
large hemorrhage took place in this same eye, followed by iritis, a
dislocation of the lens into the vitreous and the development of
absolute glaucoma requiring enucleation.) Large, oval-shaped,
blanched area, which includes the disc and macula. Cherry-red spot
at the macula. Intermediate zone of the disc shows apparently
normal except for a faint fogginess. The arteries are almost empty
and the smaller ones have the blood stream broken in different
places. The arteries have lost their light streak. The veins are
slightly distended, but not tortuous; the light streak is almost lost
in the veins, but can be faintly seen.
164
PLATE II
Embolism of the Central Rrtzrij
PERNICIOUS ANEMIA. 1 67
Anemia. Atrophy (Plate X.).
Relative size of arteries and Arteries smaller and in late
veins remains about the same, stage of atrophy are reduced
vessels may not be uniformly in number. In early stage
filled. veins are larger. In late stage
veins are diminished, and not
readily distinguished from ar-
teries.
Disc surface not sunken. Disc surface in late stage is
sunken, becoming concave or
saucer shaped.
Pallor due to want of blood and Pallor due to shrunken capil-
hence capillaries in the disc do laries in disc and also increase
not appear. of connective tissue.
Causes of Anemia. Fainting and loss of blood
and general anemia will cause pallor of the retina
and disc. Pallor of the retina and disc is also seen
in true migraine and may also be caused temporarily
by toxic doses of quinine and salicylic acid.
Treatment. Iron and arsenic, etc., for the gen-
eral anemia; appropriate treatment for the weak
heart.
Pernicious Anemia. The retina in pernicious
anemia is not actively inflamed. The disc appears
pale and the edges woolly, so that the retina and
disc are not separated by any sharp line. The eye
ground appears of a yellowish cast. Small hemor-
rhages appear in the nerve fiber layer and are there-
fore flame-shaped. Hemorrhages in pernicious
anemia are not a constant condition. This condi-
tion of the retina is also seen in hemophilia, purpura,
malaria, scurvy (scorbutic anemia), etc.
Embolism or Thrombosis of Central Artery of
the Retina (Plate II.). When there is complete
1 68 THE OPHTHALMOSCOPE.
occlusion of the central artery of the retina (if
seen shortly after the plugging has taken place)
then the following changes will be observed:
1. Change in Arteries. The large vessels are re-
duced to white lines, appearing like white threads,
and the small arteries cannot be seen. Here and
there in an artery may be seen some portion of
the blood stream broken into sections.
2. Changes in Veins. These may be normal but
usually they are contracted and show irregularities.
3. Changes in Disc. The disc appears pale as the
capillaries are not distended.
4. Changes in Retina. The central portion of
this structure is swollen or edematous and grayish-
white in color, embracing the macula and disc, giv-
ing the appearance of a large horizontally oval area
of edema. The peripheral portion of the retina is
not similarly involved. Many small hemorrhages
may be present. A cherry red spot occupies the
fovea, resembling a round hemorrhage. This
cherry red spot is caused by the red of the cho-
roid appearing through the retina at the macula.
Embolism affecting a branch of the central
artery gives a picture of changes consistent with
the retina correspondingly affected, but the
cherry red spot may not be present. The dilated
vessel up to the point of plugging may be distinctly
seen and the remainder of the vessel lie empty, look-
ing like a white thread or containing sections of the
blood stream. Several weeks after the embolus
EMBOLISM OF RETINA. 169
has plugged the artery, the swelling of the retina
gradually disappears and with the disc undergoes
atrophy. The vessels of the retina diminish until
they appear like white threads. Cholesterin crys-
tals and pigmentation may make their appearance
principally about the disc and macula. As soon as
plugging of the central artery takes place, central
vision is promptly lost. If the eye happens to be
supplied with a cilio-retinal vessel (see Chapter IV.
and Plate I. ) then some central vision may be main-
tained, otherwise central vision would be cut off.
Embolism of a branch of the artery will cut off the
vision in the field corresponding to that portion of
the retina supplied by this branch, and vision may
remain quite good or normal at the macula.
Cause. This cannot be definitely determined.
The most common cause is some disease in or about
the heart. Valvular disease, vegetations, endocar-
ditis, aneurism of the aorta and carotid, changes in
the vessel walls (endarteritis and sclerosis), syph-
ilis, nephritis, pregnancy, etc. Usually one eye
alone is affected.
Diagnosis. Sudden stoppage of the blood
stream in the arteries, edema (opacity) in the
retina, cherry red spot in macula.
Sudden loss of vision, and without pain, although
there may have been some few premonitions, such
as slight dizziness, slight headache, and possibly
flashes of light. These same symptoms sometimes
precede detachment of the retina.
170 THE OPHTHALMOSCOPE.
Prognosis. While this is most unfavorable, as
atrophy usually follows and blindness is the final
outcome, yet the presence of a cilio-retinal vessel
leaves some hope for what would otherwise be con-
sidered an almost hopeless condition.
Treatment. With an unfavorable prognosis,
treatment seems almost a waste of time and energy.
Yet treatment must not be withheld," as some good
may be accomplished and has been accomplished in
a few instances. If a history of syphilis is ob-
tained or suspected the case should be treated vigor-
ously along these lines, viz., mercurial inunctions,
pilocarpin sweats, and internally the iodid of pot-
ash should be pushed to the extreme point of toler-
ance. In fact, the iodid is indicated in nearly every
instance. The patient's heart should have careful
consideration and treatment if necessary. Digital
massage to the eye and nitrate of amyl and digitalis
internally are recommended.
Thrombosis of the Central Vein (Plate III.).
When this condition is complete the following
changes will be observed :
1. Changes in the Disc. The disc appears ele-
vated, hazy, or opaque and its margins indistinct
and striated, and late in the disease, may be hidden
from view.
2. Changes in Retina. The entire eye ground is
covered with many large hemorrhages, some pink
in color but most of them very dark red with flame-
shaped edges. The retina itself is foggy and
PLATE III.
THROMBOSIS OF THE CENTRAL VEIN OF THE LEFT EYE. ALSO CALLED
APOPLEXY OF THE RETINA AND HEMORRHAGIC RETINITIS.
Mr. A. G. B. Aged 65 years.
History. Good health until two years before coming under obser-
vation. At that time developed a swelling in right side of the neck
which was removed at Presbyterian Hospital in Philadelphia and
microscopically diagnosed as epithelioma. A second operation at
the same hospital six months later for the same condition ; the
wound never healed and patient refused further surgical interfer-
ence. First noticed failing vision and everything appearing of a
red color five days before coming under observation.
Vision of right eye 20/20. Vision of left eye 1/120.
Fundus Changes. Fundus of right eye almost normal except for
one or two small flame-shaped hemorrhages in neighborhood of the
macula.
Left Eye. Acute papillitis. Disc very much swollen and apex
seen with + 4 D. and fundus without any lens at the sight hole.
Arteries small and very few of them in view. The veins are very
tortuous, looking like half hoops or serpentine, hence the condition
as described in the text of " Medusa Nerve." The light streak in
the veins is conspicuous at the top of each loop. The hemorrhages
are of all sizes and shapes and shades of red.
172
PLATE III
Thrombosis of the Central Vein
(So- called Hemorrhagic Retinitis)
THROMBOSIS OF CENTRAL VEIN. 175
sooner or later becomes of a yellowish-gray color.
3. Changes in Veins. The veins are full and
tortuous and have a blackish appearance and pulsa-
tion may be detected. The appearance of the veins
has been compared to the hair of Medusa.
4. Changes in Arteries. These are small ana
may be hidden or invisible. The vitreous usually
contains opacities.
If thrombosis affects a branch of the vein, then
the above conditions would be in keeping for the
corresponding portion of the retina.
Cause. Thrombosis usually occurs in elderly
people who suffer with atheroma or heart disease.
Phlegmons, abscesses, erysipelas and inflammatory
diseases of the orbit are a few of the causes of
venous thrombosis in the retina. Both eyes may be
affected, especially if erysipelas is the cause, though
usually one eye alone is affected. Prognosis is most
unfavorable, as blindness usually follows and pos-
sibly enucleation may be necessary (see Apoplexy
of the Retina).
Treatment. This is of very little avail and must
be directed to the underlying cause.
16
CHAPTER VIII.
DISEASES OF THE RETINA.
Diseases of the Retina. These are many and
are named principally from the underlying cause,
but no matter what the cause may be, the ophthal-
moscope reveals one or more of the many changes
described on the following pages.
Inflammation of the Retina Without Regard
to its Variety. For very good reasons inflamma-
tion of the retina may be divided into two kinds,
superficial and deep, or inflammation of the inner
layers and inflammation of the outer or deeper
layers. When the inflammation affects the inner
layers the ophthalmoscopic picture is most conspic-
uous, and yet with all the conspicuous disturb-
ance in the retina central vision may not, for the time
being, be seriously damaged, whereas, when inflam-
mation affects the deeper layers there may not be
such apparent or prominent changes, and yet the
vision may be very much diminished. It is hardly
necessary to state that it is not always possible to
have an inflammation limited to the inner or deeper
layers by themselves, for the inflammation may pass
from one to the other in a very short time. Inflam-
mation of the retina may also extend to the underly-
ing choroid, producing retino-choroiditis, and vice
176
DISTORTION OF OBJECTS. I 7 ^
versa, inflammation of the choroid may extend to
the retina, producing chorio-retinitis, but a simple
inflammation of the retina, while it may not produce
a choroiditis at the same time, may, by virtue of the
retinitis, give the choroid an unnatural appearance,
as if it were rough or granular, spoken of as " gran-
ular changes in the choroid."
Change in Visual Acuity. This depends upon
the part of the retina affected and also upon the
extent of the inflammation. Central vision will
remain good if the center of the macula is not in-
volved or central vision diminishes in proportion to
the amount of involvement of the macula and fovea.
The chart for the field of vision will show contrac-
tion and occasionally scotomata.
Distortion of Objects. Objects may appear
smaller than normal (micropsia), or may appear
out of their normal shape or alinement (meta-
morphopsia), when the rods and cones have been
crowded together or separated or changed from
their normal level by inflammation, swelling or
exudates.
Diagnosis. A positive diagnosis of retinitis is
an opacity or loss of transparency of this mem-
brane ; the other conditions, i. e., hemorrhages, exu-
dates, pigmentation, etc., may add color to the
picture.
Prognosis. This depends on the cause, the part
of the retina involved, and the extent of the in-
flammation. The prognosis is most favorable when
I 7 THE OPHTHALMOSCOPE.
the retinitis is due to syphilis and the inflammation
is not too extensive by the time the patient comes
under observation. When the retinitis is due to
Bright's disease or diabetes or brain tumor or men-
ingitis the prognosis is certainly grave.
Course and Complications. Retinitis may be
acute or chronic. It may be complicated with in-
flammation of the choroid (retino-choroiditis)
(Plate XI.) with inflammation of the papilla
(neuro-retinitis) (Plate IV.) ; with inflammation
of the iris and ciliary body. Eventually, after the
retinitis subsides, the retina may atrophy. The
central and peripheral vision in this disease is af-
fected according to the amount and part of the
retina involved.
Treatment of Retinitis in General. The treat-
ment of retinitis resolves itself into the treatment of
the underlying cause, and also in keeping the retina
at rest by the use of a cycloplegic and dark glasses ;
blood letting from the temples, the use of pilocarpin
sweats, and attention to the general condition.
Changes in the Retina indicative of disease are
the following: (i) opacities, (2) edema, (3) exu-
dations, (4) hemorrhages, (5) pigment changes,
(6) changes in the vascularity, (7) detachment, and
(8) atrophy.
Opacities. The one condition of the retina per se
which is distinctively pathologic is its loss of trans-
parency commonly spoken of as opacity. A similar
condition or loss of transparency, also spoken of as
OPACITIES. I 79
opacity, occurs in the cornea, lens and vitreous and
is an early manifestation of alteration in any one
of these structures. As already stated the retinal
fibers lying in front of the pigment layer are trans-
parent in health, and it is this quality of losing this
transparency as an early manifestation of disease
or injury that gives the observer the opportunity to
make an early diagnosis of retinitis. The beginner
in ophthalmoscopy should make a permanent mental
impression of this and other facts, to be mentioned
later, so that he will not make a hasty diagnosis of
retinitis simply because the eye ground looks unusu-
ally red. An opacity of the retina may be very
slight or faint, resembling a slight fog or mist (Plate
II. ), or the opacity may be very dense, resembling a
white cloud (Plate IV.), or the density of the opacity
may be intermediate between these two extremes
( Plate V. ) . With the direct method of examination
there is no glass in the ophthalmoscope which will
give a clear cut picture of the fundus at the place of
the opacity. Opacities may be small or large, just
one, or a few, or a great many ; they may be scattered
throughout the retina, or they may be quite uniform
and occupy most of the retina or only a small portion
of it. It must also be borne in mind that the retina
is thick at the disc and thin at the macula, and there-
fore the want of transparency becomes most con-
spicuous at the disc when this is the portion in-
volved, whereas an opacity at the macula, which
is the thinnest part of the retina, does not hide or
l8o THE OPHTHALMOSCOPE.
veil the underlying structures to the same extent
that it would otherwise, and hence the macula may
show as a crimson spot during a certain stage of
retinitis (see Embolism of Central Artery, and
Plate II.). It has already been stated that the
cornea, lens and vitreous will also show opacity as
a pathologic characteristic, and therefore if an
opacity in one or all of these structures is present
care must be taken to differentiate them as follows :
Opacities of the cornea and lens are to be studied
with oblique light (Figs. 16, 17 and 18). Diffuse
cloudiness of the vitreous is to be examined with
the ophthalmoscope and is seen to be the same, no
matter in which direction the eye is turned, and
the blurred retinal vessels on the disc and in the
fundus appear equally obscure through the foggy
or opaque vitreous. If the vitreous cloud lies well
forward in the vitreous, just back of the lens, then
it may be seen with the oblique light and condensing
lens.
In opacity of the retina, however, some vessels
may be focused clearly while others may be obscure ;
these latter being obscured by the retinal opacity
(Plate IV.). The periphery of the retina is most
clearly seen as a rule, as it is usually free from
opacities. It is well to remember that it is not
impossible to have opacities of the cornea, lens, vit-
reous and retina in one eye at one and the same time.
Edema. Edema of the retina may be described
as a progressive or advanced opacity of this struc-
EXUDATION. l8l
ture, and, like opacity, may be limited to a certain
portion or may be diffuse throughout the retina.
As edema means swelling, the retinal vessels may
be seen passing over or through the edematous
area with resulting changes in their appearance,
viz., they lose their light streak, appear dark and
the arteries and veins, while in the swollen portion
of the retina, cannot always be distinguished from
each other (Plate V.).
Exudation. This is an inflammatory product,
or it may be metastatic, usually circumscribed and
may appear as small dots (Plate V.), or as large
masses covering extensive areas (Plate IV.). The
blood vessels that pass through or over these exu-
dations, give an exaggerated picture of the condi-
tion as seen in edema. The periphery of the eye
ground is not usually involved to the same extent
as the neighborhood of the disc (Plate IV.). Ex-
udates are often spoken of as serous, albuminous
and purulent. The serous are more or less grayish
in color, or even white (Plate IV.), and may con-
tain lymph corpuscles. The albuminous are yellow
or yellowish-white in color (Plate V.), and later
may contain connective tissue. The purulent exu-
date usually involves the vitreous to such an extent
that unless seen very early no view of the retina
can be made out, the vitreous seeming to be filled
with a large yellowish mass. Seen early, small
round yellow dots would be recognized in and about
the disc and macula.
1 82 THE OPHTHALMOSCOPE.
For a description of hemorrhages, pigment
changes and changes in vascularity, see Chapter
VII.
Diffuse Retinitis; Serous Retinitis; Edema of
the Retina; Retinitis Simplex. This may be en-
tirely local or a local manifestation of a constitu-
tional disease. As the name (diffuse) implies, the
inflammation is usually quite extensive and occupies
a considerable portion of the retina; or it may in-
volve only a small part or parts of the retina ( Plate
V.). One or both eyes may be affected. The in-
flammation may affect the inner or the outer layers,
but the inner layers are usually the ones affected.
The ophthalmoscope reveals a grayish color of the
retina; this may be very faint, like a gauzy veil,
or dense like a heavy fog, and this latter obscures
the retinal vessels. The chief characteristic of this
disease is the infiltration which causes the edema
and opacity of the retina. The arteries appear
straight and without any increase in size, possibly
they may be smaller than normal, whereas the
veins are increased in size and tortuous, and in
severe cases have an antero-posterior curve (Plate
V.). Diffuse retinitis accompanies choked disc, or
any inflammation of the disc may show some fog-
ging of the retina in its neighborhood or extending
out from the disc in the course of some one or more
of the larger vessels (Plates III., V.). Hemor-
rhages are not as common in diffuse retinitis as in
other varieties of inflammation of this structure.
DIFFUSE RETINITIS OF RETINA. 183
When hemorrhages are seen in diffuse retinitis
they are usually small and striated and are usually
seen in the course of the vessels. The white areas
and the macular star-shaped figure are not often
seen in diffuse retinitis; they are to be found in
the albuminuric retinitis, but if they do occur in the
diffuse retinitis they signify that the outer layers
of the retina are involved. Naturally, too, if the
inner layers of the retina are seriously involved
the vitreous soon becomes implicated and diffuse
opacities of this structure are seen, and they in
turn increase the obscurity of the retinal picture.
Diffuse Retinitis of the Outer Layers of the
Retina. The inflammation of these layers lies
posterior to the vessels which may be plainly seen.
The hemorrhages are more or less rounded and not
flame-shaped. The exudate is inclined to be yellow-
ish and not gray. If the pigment layer is involved,
then when the inflammation begins to subside the
granules of pigment may be seen collected in irregu-
lar spots. If the inflammation extends deeper the
choroid becomes involved and the condition is one
of retino-choroiditis.
Cause. Exposure to bright light (snow blind-
ness), electric light, lightning, taking cold, sudden
stoppage of perspiration after violent exercise;
syphilis, congenital or acquired. In some instances
it is impossible to find a cause.
Treatment. Rest of the retina with cycloplegic
and dark glasses, and treatment of the cause.
184 THE OPHTHALMOSCOPE.
Prognosis. This depends upon the cause. If
from syphilis the retinitis may clear up in a few
weeks under energetic specific treatment. When due
to other causes the prognosis is not quite so favor-
able. If the diffuse retinitis is of long standing it
may eventuate in atrophy of the retina with marked
failure, in vision; this latter is especially true if
the deep layers are involved. In other cases there
may be a formation of new vessels which are pro-
jected into the vitreous.
Circumscribed Retinitis. This is an inflamma-
tion of the retina which is limited in its extent, hence
called " circumscribed." It is often seen to follow
the course of the large vessels (Plate V.). Circum-
scribed retinitis at the macula, if in the deep layers
and affecting the pigment layer, seriously impairs
central vision and may destroy it. A consideration
of circumscribed retinitis is but a consideration of
the diffuse variety of retinitis, but limited in its
extent. Virtually diffuse and circumscribed retin-
itis are therefore one and the same disease. The
causes of each, however, are not always the same.
Retinitis Punctata. Some authorities object to
this name, as the ophthalmoscope does not reveal
any decided inflammation, and the same may be said
about retinitis pigmentosa; however, these diseases
do have a low grade of inflammation as revealed
by the microscope. As its name implies (retinitis
punctata), the ophthalmoscope reveals many minute
white or yellowish-colored dots, and these are best
RETINITIS PUNCTATA. 185
seen with the direct method, and as they are very
closely packed together they give a stippled appear-
ance to that portion of the retina where found,
and this is usually between the macula .and the
disc. The spots are not always in this location, but
may be scattered over the fundus, and while they
are usually round in shape they may occasionally
appear oval.
These punctate changes have been variously de-
scribed or classified and named by different ob-
servers and referred to as " dots " as follows :
Nettleship's Dots. These dots are quite small
and numerous, dead white in color, not glistening;
they occupy the space between macula and periph-
ery, and have been seen scattered over the fundus.
Gunn's Dots (also called " Crick's " Dots).
These dots are quite small and few in number, yel-
lowish in color and occupy the macular region. A
rare condition, and found usually in young subjects.
Retinitis punctata albescens of Mooren resembles
Nettleship's dots and gives night blindness as a
symptom. The ophthalmoscope reveals the fundus
having many or a few white dots which are small
and round in form.
Punctate retinitis is found in the eyes of old
people who have atheromatous vessels, whereas
Gunn's dots are found in the eyes of young patients.
Prognosis. Not unfavorable as vision is not
usually impaired, except possibly for some slight
I 86 THE OPHTHALMOSCOPE.
contraction in the field or for a moderate amount
of night blindness.
Treatment. Xot benefited by any treatment
though electricity, alteratives, etc., have been tried
and recommended.
Apoplexy of Retina (see Plate III.). The dis-
ease under consideration partakes of the nature of
a disease of the walls of the vessels and this so
weakens them that the blood corpuscles make their
escape into the retina, a condition primarily of vas-
culitis. Retinitis may now develop from the
presence of the blood, the blood being the exciting
cause of the retinitis. If the hemorrhage is a large
one, or many smaller hemorrhages coalesce, the
intra-ocular pressure may become so increased as
to develop acute glaucoma (hemorrhagic glau-
coma). In apoplexy of the retina the arteries are
smaller than normal. This condition of the arteries
might lead one to suppose, that the hemorrhage
was from a break in the vessel, but this must be a
mistake as specimens examined fail to reveal any
ruptures. Hemorrhages are usually from the large
vessels, therefore they are seen in the neighbor-
hood of the disc or possibly on the disc itself; these
hemorrhages may be few or many, they may vary
in size and shape, though they are usually quite
large as compared to hemorrhages occurring in
other varieties of retinitis (see Plate VI.). Apo-
plexy of the retina is usually a condition of the
aged and often accompanies changes in the circula-
IIEMORRHAGIC RETINITIS. 187
tion and heart, and it may be a prodrome of cerebral
apoplexy.
Causes. Usually diseases of heart and blood
vessels, with the underlying cause for the change in
the blood and vessel walls, arterio-sclerosis, etc.
Prognosis. Very unfavorable.
Treatment. Rest and treatment of underlying
cause.
Hemorrhagic Retinitis. Hemorrhages in the
retina without inflammation of the retina may be
called apoplexy of the retina. The true name for
hemorrhagic retinitis is therefore an inflammation
of the retina with accompanying hemorrhages.
Apoplexy of the retina, or a hemorrhage in the
retina will produce an inflammation of the retina
and hence is called hemorrhagic retinitis. Apoplexy
of the retina usually eventuates into hemorrhagic
retinitis. The ophthalmoscope reveals a cloudy
retina with swollen disc which has its edges ob-
scured. The arteries are small and veins large and
tortuous. The hemorrhages are many and varied ;
round, flame-shaped, linear and irregular and ap-
pear throughout the eye ground.
Causes. Disease of heart and blood vessels;
abnormal suppression of menses ; syphilis, etc.
Prognosis. This is usually quite grave as the
underlying cause may be a structural change in
the walls of the vessels or the heart may be seri-
ously involved. Vision is liable to serious and per-
manent injury from the same cause. When caused
by syphilis the prognosis is rather more favorable.
I 88 THE OPHTHALMOSCOPE.
Treatment. Rest of the eye or eyes, as the dis-
ease may be monocular; with appropriate treat-
ment for the underlying cause.
Syphilitic Retinitis. While syphilis is one of
the most common causes of retinitis it is interesting
to note the fact, that there is no one variety of
retinitis that is typically syphilitic. The nearest
approach to this is the diffuse variety, but it only
proves that syphilis may be manifest in the retina
by affecting the superficial or deep layers or it may
be circumscribed, or the retinitis may be accom-
panied by choroiditis (syphilitic retino-choroiditis)
(Plate XL), or the vitreous, ciliary body and iris
may also be affected at one and the same time, or
singly. Hemorrhages are not usually the conspicu-
ous factors in syphilitic retinitis as in some varieties
of retinitis, though they do occur at times and are
often quite large. The vision is often markedly
affected or impaired, depending of course upon the
stage of the disease, its variety and the part of the
eye ground involved.
Course and Treatment. This disease is usually
chronic. The treatment of course is anti-syphilitic.
Mercurial inunctions, iodids internally and the use
of pilocarpin sweats. The prognosis depends on
the stage of the inflammation, the part of the retina
involved and the persistence and vigor with which
the treatment is carried out and maintained.
Splenic or Leukemic Retinitis, Retinitis from
Anemia. The early ophthalmoscopic changes of
this disease are not unlike those of diffuse retinitis,
PLATE IV.
ALBUMINURIC RETINITIS. RETINITIS OF BRIGHT'S DISEASE. BRIGHT'S
RETINA. FUNDUS OF RIGHT EYE. DIRECT METHOD.
Miss K. C. Aged 49 years.
History. First noticed foggy vision in April, 1904, and came for
examination October 8 of same year, stating that when left eye was
closed objects seen with right eye were quite indistinct on their
left side (positive scotoma).
Vision of right eye with + -5 D- C + i-SO Cyl. axis 180 de-
grees = IV/XX.
Vision of left eye with + 0.50 D. C + J -5o Cyl. axis 180 de-
grees = IV/VIISS.
Fundus Changes. Fundus of each eye very similar, but that of
the right typically marked. Swollen disc, striated edges; exuda-
tions (" snow banks ") about its edges with two areas above and
one below the disc. Macular figure unusually well marked. Many
scattered and flame-shaped hemorrhages seen in the periphery and
about the disc. Vessels about the disc show effusion into their
sheaths by the white edge at each side of the vessel. The disc
resembles that of choked disc in brain tumor, but the " snow banks "
and macular figure are almost too conspicuous for such a diagnosis.
The history of the patient, not having any headache, nausea or
vomiting, no double vision or any indication of extra-ocular palsies,
excluded the idea of brain tumor. The urine analysis confirmed
the kidney changes (interstitial nephritis).
Decapsulation of each kidney was performed February 25, 1905,
and patient died fourteen days later of uremic coma.
190
PLATE IV
Rlbuminuric Kstinitis
SPLENIC RETINITIS. 193
but later on the fundus may, and often does, appear
of a light orange color, which authorities recognize
as quite characteristic of this variety of retinitis,
and yet there are cases of splenic retinitis which do
not have this characteristic feature. The veins fre-
quently have an unusual tortuosity and are quite
distended and of a rose red color. The arteries ap-
pear normal and of an orange yellow color. The
disc may appear normal or it may be prominent, and
if prominent its edges are hazy. Hemorrhages
both large and small are seen in any part of the
fundus, but usually about the equator ; they are cir-
cular in form. Hemorrhages may also be seen in
the macular region and about the disc. As the old
hemorrhages disappear new ones are seen to make
their appearance. The hemorrhages surround ele-
vated white spots which vary in size and are com-
posed of lymph corpuscles.
Treatment. This applies to the cause.
Renal Retinitis, Retinitis of Bright's Disease,
Retinitis Nephritica, Albuminuric Retinitis,
Papillo-retinitis (Plate IV.). This may occur in
any variety of disease of the kidneys, especially in
the chronic form, most frequently with contracted
kidney, also with the large white kidney. The
most common variety of retinitis is the neuro-retin-
itis (papillo-retinitis). The ophthalmoscope reveals
the following characteristics: (a) The disc is
swollen and hyperemic or actively inflamed; (b)
large, round, white or yellowish-white massings ar-
'7
194 THE OPHTHALMOSCOPE.
ranged in circular form are seen to partly or com-
pletely surround the disc; this is quite distinctive of
albuminuric retinitis, whereas in other varieties
of retinitis the exudate is not so rounded but elon-
gated and follows the course of the large vessels.
The massings around the disc have been called
" snow bank," and the name is obvious, (c) White
spots, small in size, seen at the macula (due to fatty
degeneration of exudates and retinal elements)
form a characteristic picture of Bright's disease.
These white dots appear early in the disease and
later on they enlarge or coalesce into radiations like
the spokes of a wheel, with the macula as a center,
their radiations resemble the points of a star
and the figure has been called " stellar " or " macu-
lar figure " ; this figure is not always complete.
However, whether complete or partial, it is con-
sidered quite pathognomonic of Bright's disease
until other factors can be brought out to disprove
this diagnosis. Therefore, the macular white dots
are sometimes seen in other varieties of inflamma-
tion of the retina, (d) Many of the retinal vessels
will be seen to pass over or are hidden in the white
patches. The arteries appear normal or smaller
in size, and the veins are distended, slightly tortuous
and dark in color. Arteries and veins may show
a white streak at their borders, (e) Hemorrhages
may occur at any time during the progress of the
disease; they are usually in the nerve fiber layer
and therefore flame-shaped. Small hemorrhages
DIAGNOSIS OF RENAL RETINITIS. 1 95
in the deep layers (round-shaped hemorrhages), as
an early manifestation, foretell a most unfavorable
prognosis.
Differential Diagnosis. Retinitis of Bright's
disease may be mistaken for retinitis accompanying
brain tumor, and this differentiation is not always
easy or positive from the eye condition alone ; how-
ever, the following may assist materially in the
decision.
Bright's Disease. Brain Tumor.
Disc usually has uniform or dif- Disc very much elevated and
fuse redness and occasionally vessels seen passing down into
a slight swelling, and vessels level of retina (Plate III.).
buried in the swelling which
is not as prominent as in
choked disc.
Large vessels show very little Veins very large, full and tortu-
change, the veins may be ous very early in the disease.
slightly tortuous and darker in
' color.
Retinal changes appear early. Retinal changes come late.
White exudates are numerous White exudates not so early.
and coalesce ; seen around disc Macular star may not be
and at the macular region. present.
Albuminuric retinitis rarely affects one eye
alone ; both eyes are usually affected, but one may
be affected before its fellow.
The above description is that of a typical case
of albuminuric retinitis, but there are many de-
partures from this complete picture; in fact, the
complete picture is not the common one. There are
four other principal pictures of albuminuric retin-
itis, described and named from a chief feature seen
in the fundus.
196 THE OPHTHALMOSCOPE.
1. Degenerative Albuminuric Retinitis. In
this picture the whitish ring about the disc is ab-
sent and the stellate figure about the macula is not
complete. The disc is red and swollen but not
highly inflamed; its edges are hazy. The hemor-
rhages are nearly, if not all, flame-shaped, occupy-
ing the nerve fiber layer.
2. Hemorrhagic Retinitis of Bright's Disease.
As its name implies, this variety is characterized
by many hemorrhages scattered over the fundus,
and they appear as an early manifestation before
the disc becomes involved. When the hemor-
rhages are absorbed white areas take their places,
and if the underlying choroid has been involved,
these areas may be partially pigmented.
3. Albuminuric Neuro-retinitis (Plate V.).
Here the picture is one of high grade inflamma-
tion of the disc and retina with hemorrhages and
exudates as a consequence of such inflammation.
4. Albuminuric Papillitis. The chief charac-
teristic feature here is the inflammation of the disc,
giving the typical "choked disc" (papillitis).
Albuminuric retinitis occurring during preg-
nancy is the neuro-retinitis just described. The
white areas are large and scattered and due to
serous effusion ; the hemorrhages are also scattered.
The white areas do not usually have the same radi-
ating figure in the macula as in the typical picture
described and shown in Plate IV.
Prognosis for Vision. Vision is usually ma-
PLATE V
lilbuminuric Retinitis of Pregnancy
PLATE V.
ALBUMINURIC RETINITIS OF PREGNANCY. NEURO-RETINITIS.
PAPILLO-RETINITIS. FUNDUS OF LEFT EYE.
DIRECT METHOD.
Mrs. O. Aged 28 years.
Fundus Changes. Each fundus of this patient showed neuro-
retinitis, but much more marked in the left, although the right eye
had its vision destroyed by a large hemorrhage into the macula.
Vision of right eye with + i D. C + I-5O Cyl. axis 100 degrees =
light perception.
Vision of left eye with -f- 1.50 D. C + 2.50 Cyl. axis 90 degrees =
V/XIK?).
The disc is hidden and slightly swollen, but not to the same ex-
tent as in Plate IV. The punctate dots above and at the macula
(neuritic dots) are quite conspicuous. Areas of exudation are
some distance from the disc. The hemorrhages are numerous, small
and flame-shaped. The veins are full and tortuous and some of
them are covered by the swollen retina. Patient recovered her
health, but with damaged vision, as above recorded, with her cor-
recting glasses. The following letter from Dr. Davis is self-ex-
planatory and gives the patient's history :
April 14, 1905.
DR. JAMES THORINGTON,
120 South :8th Street, Phila.
My Dear Dr. Thorington: Regarding our patient, Mrs. O. at
the Polyclinic, the salient points of the history are as follows :
Patient, aged 28; multipara; family history, negative; has had
scarlet fever and diphtheria. No complications in previous preg-
nancies or labors ; has had chlorosis ; and has had frequent head-
aches at menstruation ; has worn glasses.
During pregnancy which has just terminated, felt languid, had
occasional nose-bleed and slight vaginal hemorrhage. She received
no competent medical care. Her urine was not examined. On the
evening preceding admission to Polyclinic Hospital she felt badly
and was nauseated. Convulsions began in the early morning. She
had eight before admission. Temperature on admission was 102.
A convulsion occurred immediately after admission. She was
treated by venesection with intravenous transfusion of salt solution,
hot packs with copious enteroclysis. Labor gradually came on, and
when the cervix had softened and partly dilated, the patient by
podalic version was delivered of a dead 7-months child, 35 centi-
metres long. She had no convulsion after delivery, and slowly
regained consciousness.
I 9 7
The placenta was not examined, nor- was the fetus submitted to
examination.
Examination of the patient's urine, with the clinical history of
her case, shows that her eclampsia was the result of toxemia of
nephritic origin. That this had proceeded sufficiently far to pro-
duce disintegration of the red blood corpuscles was shown by the
fact that the patient had nasal and vaginal hemorrhage before labor,
and also from the occurrence of retinal hemorrhages, as reported
by you.
So far as prognosis for life is concerned, these cases are more
favorable than toxemia of nephritic origin.
This patient will gradually recover her usual general health, and
can avoid a subsequent toxemia, should pregnancy again occur.
In other cases which I have seen, the eye condition has gradually
improved, and patients who were practically blind, before delivery,
have obtained fair vision.
The treatment employed in this case was that which I usually
employ with these patients ; namely, the abstraction of a small quan-
tity of blood, followed by intravenous saline transfusion to neutral-
ize poisons circulating in the blood serum, copious lavage of the
stomach and intestines, with perspiration as free as possible. When
labor begins, it is aided and not allowed to continue long. Hoping
that these notes will be what you desire, I remain,
Very truly yours,
EDW. P. DAVIS.
198
PLATE VI.
RETINITIS DIABETICA. FUNDUS OF RIGHT EYE. DIRECT METHOD.
Mr. C. B. E. Aged 64 years.
History. Suffering from diabetes for three years and sight of
each eye has been failing gradually for the past three months, but
within the last few days has not been able to read with any glasses
he could purchase. Now his vision is so defective he has difficulty
in getting around the city and is afraid of getting run over.
Fundus Changes. Arteriosclerosis showing in the upper and
lower temporal vessels where they cross. Small flame-shaped and
round hemorrhages scattered irregularly in the fundus. The disc
edges are foggy and the membrana cribrosa is indistinct. The inter-
mediate zone and in fact the entire disc has a canary yellow color
appearance. Fundus of the left eye is practically the same as the
right.
Vision of right eye with -j- i D. C + ! Cyl. axis 180 degrees =
VI/XL.
Vision of the left eye with same correction is the same as the
right.
Cannot read newspaper print with any additional glass.
202
PLATE VI
Retinitis Diabetica
PROGNOSIS FOR PATIENTS LIFE. 205
terially damaged and may be destroyed as the vital
part of the eye (the macula) is seriously involved,
as a rule. The failing vision may be the very first
symptom which brings the patient's attention to his
eyes, and hence to his kidney condition.
Prognosis for Patient's Life. Most patients
with albuminuric retinitis (except when due to
pregnancy) die within two years (fourteen months
has been given as the average) from the time the
retinas are primarily involved. There are excep-
tions to this statement. The writer has the personal
knowledge and has examined the eyes of a col-
league's patient, who has had albuminuric retinitis
for over ten years, and who was told nine years ago
that he would not live another year. The writer has
under observation two cases of albuminuric retinitis
that have existed for over two years, and both pa-
tients are in fairly good health ; both these patients
are syphilitic and have been, and are irregularly un-
der specific treatment. It is the writer's belief and
experience that syphilitic patients, with albuminuric
retinitis, coming under active specific treatment give
a much more favorable prognosis for a longer life
than a patient ivho develops Bright's retinitis with-
out this specific (cause?) history.
Treatment. This applies directly to the kidneys
and the underlying cause. As far as the eyes are
concerned, they should be placed at rest with dark
glasses and the use of a cycloplegic, and all use of
the eyes at any near work must be stopped.
18
206 THE OPHTHALMOSCOPE.
Diabetic Retinitis (Plate VI.). Involvement of
the retina is not a common condition in diabetes,
it is usually a late manifestation, but when it
does occur it is quite serious. Diabetes does,
however, produce quite marked and rapid changes
in the refraction by its action on the lens, and
so-called diabetic cataract may be a result. The
snow bank about the disc and the macular star are
usually absent in diabetes. The hemorrhages are
common, flame-shaped and round and usually large.
The disc is not markedly swollen ; late in the disease
it may appear of a pale yellow color. However,
there are instances when diabetic retinitis simulates
the albuminuric variety so closely that the presence
of sugar or albumen in the urine must settle the
diagnosis, or possibly both conditions (albuminuria
and diabetes) may exist in the same subject. Hem-
orrhagic retinitis may occur during diabetic retin-
itis. Choked disc may be present in diabetes, and
also with brain tumor. While Bright's disease and
also diabetes usually affect both eyes respectively
at the same time, yet either may occur in one eye
several weeks or months before the other eye is
affected.
Course and Complications. Cataract, inflam-
mation of the iris and vitreous opacities, are added
complications to the failing central and peripheral
vision.
Prognosis. Unfavorable, depending of course
upon the condition of the disc and the retinal in-
volvement and complications.
PLATE VII.
RETINITIS PIGMENTOSA. FUNDUS OF RIGHT EYE. DIRECT METHOD.
Mr. S. J. B. Aged 53 years. Cigarmaker. Englishman by birth.
Vision of right eye IV/XX with 2.50 D. C + 2 -75 Cyl. axis
i8o=IV/X.
Vision of left eye IV/XX with 2.00 D. C + 2.50 Cyl. axis 12
degrees = IV/X.
History. So far as patient knows has always had day sight
(hemeralopia), but could not see at night without a very bright
light, and has therefore remained in doors at night unless he had
company after leaving the house in the evening. Is in the habit
of hurrying home at twilight and dreads very dark or rainy days.
Knows that he had night blindness when he came to America in
1863, when about ten years of age. His condition has geen gradu-
ally getting worse. Has tried all kinds of glasses, but without much
assistance. This is proven by the above formulas. Parents are not
related and no one else in his family, so far as he knows, has ever
been similarly afflicted. Is a single man. Never had syphilis. Has
never married, as he was medically advised not to, as his eye con-
dition would very likely be inherited.
Fundus Changes. The periphery of the eye ground is character-
istic of many myopic eyes, the choroidal vessels being very conspic-
uous. The retinal vessels are not very numerous and the smaller
ones can be traced with difficulty in the periphery. The disc is
quite yellow in color. The retinal vessels are narrow. The lower
vein appears large at first, but this is due to the peculiar way in
which the pigment is deposited on its walls. The reflex immedi-
ately around the disc approximates the normal, but beyond this the
condition is atrophic. A few stellate pigment spots, together with
irregular pigment massings on the vessels, are scattered throughout
the fundus. This is an unusual variety of the disease under con-
sideration. The patient is color blind for red. See chart, Fig. 71.
208
PLATE VII
Retinitis Pigmentasa
RETINITIS PIGMENTOSA. 211
Treatment. That for diabetes.
Retinitis Pigmentosa (Plate VII.), Pigmen-
tary Degeneration of the Retina, Night-blindness
(Hemeralopia, yp-epa, day, and aty, sight). This
disease always affects both eyes (unless syphilitic),
it begins in childhood and gradually develops as
the patient grows older and if the patient lives to
be sixty years or more, then blindness will very
likely be the ultimate condition. The cause of this
peculiar disease is unknown, though statistics re-
veal the fact that about one case in three can be
traced to consanguinity of the parents. Syphilis,
congenital or acquired, is also a cause.
Pathology. The connective tissue of the entire
retina becomes thickened or hypertrophied and the
nerve elements atrophic (degenerated), this latter
gradually reducing visual acuity. The caliber of
the retinal vessels becomes narrowed by direct thick-
ening of their walls and the diameter of the ves-
sels gradually diminishes also. The retinal pig-
mentation becomes disturbed, and in a most
peculiar manner and one that has never been
satisfactorily explained.
Ophthalmoscopic Findings. The pigmentation
appears in masses or patches and is deposited in the
retina and it not only follows the course of the
retinal vessels but forms on the vessel walls; this
is quite a diagnostic feature of the disease. In
childhood or in the early stages of the disease this
pigmentation is seen only in the periphery of the
212
THE OPHTHALMOSCOPE.
eye ground but later on these spots increase in
numbers and unite, sending off filiform processes,
so that they resemble bone corpuscles, and are often
star-shaped, and there may be other pigment mass-
ings present which are most irregular and may have
a spider-shaped formation, so that the retina in
some instances looks as if it had a black network
or irregularly folded veil stretched over it. This
FIG. 71. Form Field, showing contraction in all meridians. This is
the chart of the right eye of the patient with Retinitis Pigmentosa, as
illustrated in Plate VII. The outer edge of the black area represents the
normal field and the inner edge of the black area shows the contraction.
whole process of pigmentation begins well forward
and gradually extends inward toward the disc
in a uniform manner. When seen in childhood
this process of pigmentation is not well developed
but progresses slowly as the patient grows, unless
some intercurrent disease develops when the pig-
RETINITIS PIGMENTOSA. 213
mentation may be hastened. One case under the
writer's observation (the parents of the patient were
second cousins) developed dorsal curvature of the
spine and the retinal disease increased rapidly. The
disc gradually loses its normal appearance and
takes on a yellowish-gray color and may eventually
become white, atrophic. Cases of retinitis pigmen-
tosa are often complicated with posterior polar
cataract and nystagmus, especially when congenital.
See description for Plate VII.
Subjective Symptoms. The chief characteris-
tic symptom, and the one by which the patient's
attention is first called to his condition, is the in-
ability to see distinctly when twilight begins or
after the sun goes down. He may see perfectly
well in day time so far as he knows, but after dark
he will stumble and bump into objects.
Field of Vision. The field of vision becomes
more and more contracted as the disease progresses
and atrophy develops (Fig. 71).
Central Vision. This remains good much longer
than peripheral vision, but the condition means ulti-
mate blindness if the patient survives. The re-
fractive error is not known to influence the suscepti-
bility of an eye to the disease under consideration.
Many illustrated cases would indicate that the eyes
were hypermetropic and yet the fundus shown in
Plate VII. happened to be in a stretching myopic
eye that had the choroidal circulation very much
exposed in the periphery.
214 THE OPHTHALMOSCOPE.
Differential Diagnosis. Retinitis pigmentosa is
not a common disease and ordinarily it is easily
differentiated from choroiditis or retino-choroiditis
which it is said to somewhat resemble.
Retinitis Pigmentosa Retino-choroiditis
(Plate VII.). (Plate XL).
Choroidal changes often absent. Choroidal changes present.
Pigment spots not round, but Pigment spots are round or in
stellate. form of rings or irregular
shapes.
Pigment follows course of ves- Pigment does not follow course
sels and often seen on top of of vessels to any great extent,
vessels.
Treatment of Retinitis Pigmentosa. If due
to syphilis, iodids and mercury should be ordered.
For the congenital variety strychnia and galvanism
should be tried, though the prognosis in such cases
is very grave.
Sclerosis of the Retina. Called also non-pig-
mented sclerosis. This is another variety of retin-
itis which gives a contracted field and blindness at
night ; the same symptoms are obtained as in retinitis
pigmentosa, therefore these two diseases markedly
resemble each other, but the ophthalmoscope does
not reveal the typical pigmentation just described,
but rather a pale fundus or one resembling a slow
or low grade of inflammation of the retina, and
choroid, with here and there scattered dots of pig-
ment. Several members of the same family may
have the condition, which suggests that it is con-
genital and possibly due to consanguinity of the
parents. There is no treatment of any avail.
PLATE VIII.
PARTIAL DETACHMENT OF THE RETINA. FUNDUS OF THE RIGHT EYE.
DIRECT METHOD.
Mr. M. Aged 46 years. Patient seen in consultation by Dr. G.
E. de Schweinitz.
History of Myopia. Always carefully refracted. Was struck on
the left side of the head some few days before coming under obser-
vation.
Fundus Changes. Retina detached downward and forward. The
wavy condition of the retina, the course of the dark-colored vessels
without their usual light streaks, as they appear on the detachment,
are all quite characteristic of the condition under consideration.
The disc appears foggy because it is out of focus as compared with
the detachment, which is in focus for purpose of sketching. The
disc is seen with 7 D., whereas the detachment is best seen with
a + I D- Two most peculiar and irregular white streaks with pig-
ment massings on their upper edges are seen down and out and
down and in, beginning a short distance from the disc and extend-
ing as far forward as the eye can see into the periphery. These
white streaks resemble obliterated vessels or ruptures in the choroid,
and what is still more peculiar each eye has the same condition
and in about the same situation. There is no detachment in the
left eye. The white streaks are very likely congenital and possibly
obliterated vessels. A rupture of the choroid would be crescentic
in shape and situated elsewhere in the fundus, and it is not likely
that there would be two ruptures in the same eye or in both eyes.
Each eye has compound myopic astigmatism.
See chart, Fig. 72.
Vision of right eye IV/L with 5.25 D. C 1-25 Cyl. axis 20
degrees = l prism b. d. == VI/VI.
Vision of left eye IV/CXX with 8.25 D. Z 3-25 Cyl. axis
165 degrees = i prism b. up. = VI/VI.
216
PLATE VIM
Detachment of the Retina
OPHTI-IALMOSCOPIC FINDINGS. 2IQ
Detachment of the Retina. This means that
the retina is no longer held up against the choroid
by the vitreous, the latter having become diseased
or some force greater than the vitreous pressure, has
been exerted from behind and the retina has come
forward as a consequence. This may occur in any
part of the retina either as a partial condition
(Plate VIII.) or as a total detachment; this latter
is sometimes spoken of as an umbrella detachment,
in its resemblance to a closed umbrella, the retina
remaining attached at the disc edges and the ora
serrata.
Ophthalmoscopic Findings. Viewing a fundus
having a partial detachment, the normal reflex is
absent at the portion detached and in its place is
seen a reflex more or less opaque and gray in color
with its surface uneven and more or less wavy. The
retinal vessels passing over the detachment are quite
dark, or blue-black in color, and have lost their
light streak, they have peculiar positions or curves
or bends which are in keeping with the surface of
the detachment, they appear decidedly serpentine.
The same lens in the ophthalmoscope will not focus
the same or any one vessel in all of its various posi-
tions. If the eyeball is rotated in different direc-
tions the detachment with its vessels are seen to
move according to the fluidity of the vitreous and
underlying fluid. When the retina is totally de-
tached, no view of the interior of the eye can be ob-
tained and the condition can best be examined by
22O
THE OPHTHALMOSCOPE.
having the pupil dilated and using the oblique
light. Detachment usually affects one eye alone,
though both eyes may become affected, one eye
before the other; seldom are both eyes affected
primarily at the same time unless from injury.
Occasionally it is the upper part of the retina that
detaches first and the fluid behind gradually
gravitates downward and in this way the part first
detached may settle back to its normal position and
FIG. 72. Form Field, showing the upper field cut off abruptly and also
considerable contraction down and out. This is the chart of the patient
with Partial Detachment of the retina in right eye, as illustrated in
Plate VIII.
the lower part becomes the detached portion. The
detached retina soon becomes blind. Sooner or
later, depending upon the amount of the detach-
ment, the lens becomes opaque and the eyeball re-
mains quite soft.
CAUSES OF DETACHMENT. 221
I
Visual acuity is not materially interfered with
unless the detachment is very large or involves
the macular region or the vitreous or lens become
cloudy. The field of vision is lost in the area cor-
responding to the detachment, and it is often this
one symptom which brings the patient under ob-
servation (see Chart, Fig. 72).
Causes of Detachment. The most common
cause is myopia (the stretching eyeball). Other
causes are inflammation of the retina; or ciliary
body; or uveitis; cysticercus; injuries; tumors of
the choroid; diminished intra-ocular tension fol-
lowing the removal of the lens on account of high
myopia, loss of vitreous from any cause and also
diminution in the density of the vitreous as seen in
diabetes, etc., and also from a pulling on the retina
by cicatricial bands. Detachment of the retina may
develop suddenly from straining at stool or after
stooping over or after running or after any great
exertion. A patient of the writer's developed or
noticed sudden loss of sight in the lower field after
a violent spell of sneezing and a detachment was
carefully studied and mapped out two hours later.
Retinal detachment is said to be much more common
among men than women.
Differential Diagnosis. Detachment due to
fluid and that due to a neoplasm should have careful
consideration as bearing upon the life of the pa-
tient. A growth beneath the retina would give a
somewhat similar picture to that of detachment as
222 THE OPHTHALMOSCOPE.
far as the curves in the vessels are concerned, but
they would very likely maintain their light streak
which they would not do in a fluid detachment, and
there would not be that wavy appearance to the
retina and vessels as in the fluid detachment, neither
would there be that motion to the detachment when
the eyeball was suddenly rotated, and furthermore
when the retina is raised up by a growth from the
choroid it has more definite or sharply cut edges,
as compared to a detachment from fluid.
Elevation of the Detachment. The detachment
of the retina whether due to fluid or a growth means,
that the retina in the area of detachment is brought
closer to the crystalline lens, and therefore to study
or examine it carefully a much stronger plus lens
must be employed at the sight-hole of the ophthal-
moscope if the eye is naturally hypermetropic than
would be required to see the disc, and if the eye
was myopic then a weaker minus lens or very likely
a plus lens would have to be employed to see the
vessels on the detachment. The difference in the
strength of the lenses employed to see the surround-
ing attached retina and the top of the detachment
represents the amount of the elevation, depending
of course upon the position of the growth or loose
retina, whether well forward in the eye ground or
back near the disc. Every three diopters of differ-
ence represents one millimeter of elevation. The
field of vision and the elevation carefully studied
at different times and then compared, will be a
TREATMENT OF DETACHMENT. 223
guide as to the increase or decrease in size of the
detachment or growth.
Prognosis. Most unfavorable for permanent
reattachment. Usually the detachment becomes
complete and sight destroyed.
Treatment. Enucleation of the eye, if the de-
tachment is due to a growing tumor. If due to
fluid, and the patient comes under observation quite
early, then the patient must be placed in the recum-
bent position, atropin instilled and the eye gently
bandaged. The patient must be freely purged and
following this pilocarpin sweats must be given
every night or every other night, according to the
patient's condition and according to the changes
whch take place in the eye. Subconjunctival injec-
tions of normal salt solution should be given every
second or third day. Internally the patient should
receive increasing doses of the iodid of potash. The
eye ground should be studied briefly each day to see
if the fluid is diminishing and the retina resuming
its normal position; when this has been accom-
plished the patient should remain comparatively
quiet for several days before attempting any move-
ments like walking up and down stairs. The treat-
ment by tapping the fluid through the scleral coat
and drawing off the fluid, and then injecting irri-
tants like the tincture of iodin, etc., is not considered
advisable ; all such treatment has been tried and ulti-
mate failures reported. Most every case treated
has failed of permanent reattachment, yet as some
224 THE OPHTHALMOSCOPE.
few recoveries have been reported, the treatment
should be carried out in each case, especially if seen
quite early ; the earlier the case comes under obser-
vation the better.
Rupture of the Retina. This is a most unusual
condition, though it has been recognized. A rup-
ture of the retina accompanying a corresponding
condition of the choroid is not so infrequent. If
the retina is ruptured its ragged edges will be seen
and also the exposed choroid beneath; of course
if a hemorrhage occurs at the time of the rupture
then the wound may be covered, but as soon as the
hemorrhage is absorbed the diagnosis can be made.
The retina is liable to rupture after being detached,
therefore it may be a sequela of detachment of the
retina.
Commotio Retinae, or Contusion of the Retina.
A severe blow upon the eyeball or the head with a
blunt instrument such as a ball, club, fist, etc., will
produce impaired vision, redness of the eyeball, and
dread of light (photophobia). These symptoms
will ordinarily pass away in a few hours unless
unusually severe. For the time being, however, the
ophthalmoscope reveals a slight opacity of the
retina. A guarded prognosis should be given, for
if the condition persists for some time, it may
eventuate in impaired vision which may become
permanent.
Glioma of the Retina (also called " Amaurotic
Cat's Eye). This is a disease of the retina which
GLIOMA OF RETINA. 225
occurs in infancy, very seldom after the age of six
years, though a case has been reported which oc-
curred as late as twelve years. Glioma is therefore
recognized as a disease of infancy, a congenital con-
dition, and has been known to affect more than one
child in the same family. It usually affects one eye,
but may appear in both. " Glioma is the only neo-
plasm which occurs in the retina." (Fuchs.) Gli-
oma is a non-pigmented growth springing from the
inner granular layer of the retina, and grows rap-
idly. The child is usually brought under observa-
tion with the statement from the mother or some
member of the family, that a glistening reflex from
the eye has been noticed for a certain length of
time and that the child did not appear to be seeing
with the eye or on the side corresponding to the
eye affected. Hence the name amaurotic (d/taupd?,
dark or blind).
Ophthalmoscopic Findings. No definite fun-
dus reflex can be made out unless the eye is
brought under observation quite early, but no
matter whether seen early or in the late stage of
the disease, it will be necessary to examine the eye
with the oblique light and have the pupil dilated.
The glioma is usually of a whitish-pink color and
may be irregular, lobulated or smooth.
Growth of the Glioma. This is quite rapid as a
rule, and especially so after the first stage which is
that of loss of sight and increase of tension; then
comes great pain and the growth perforates the
226 THE OPHTHALMOSCOPE.
eye in different places, usually at the nerve and the
edge of the cornea. The orbit becomes crowded
and the bleeding mass protrudes between the lids
and onto the cheek. By metastasis and continuity
of structure, the disease spreads to the internal
organs and the brain. The patient wastes away
and dies.
Differential Diagnosis. Glioma resembles
pseudo-glioma (purulent choroiditis) which is not
a malignant disease. It also resembles tubercle of
the choroid (see choroidal diseases).
Glioma. Pscudo-Glioma.
Pinkish-white color. Yellow or straw color.
Smooth or tabulated surface. Flat surface.
Iris usually pushed forward. Iris adherent posteriorly in most
instances, and its ciliary bor-
der retracted.
Anterior chamber shallow. Deep anterior chamber.
May appear vascular. Does not appear vascular.
Tension may be very much in- x Tension diminished,
creased.
Prognosis. Unfavorable unless the eye is
enucleated early. The prognosis is favorable, if
the glioma does not return within three years after
removal.
Treatment. Early enucleation and dividing the
nerve as far back as possible.
Retinitis Circinata (Described by Fuchs). The
retinal picture of this disease as seen with the oph-
thalmoscope is that of a number of glistening white
patches which are arranged in the form of an oval
about the macula, extending well upward and
AMAUROTIC FAMILY IDIOCY. 227
downward almost to the temporal vessels. Occa-
sionally the retinal vessels are seen to pass over
these white patches which resemble the patches seen
in albuminuric retinitis and diabetes. Occasion-
ally a few hemorrhages are seen in the white
areas. The macula is usually involved and its
visual quality is very much reduced. This
seems to be a disease of the macular region, as the
rest of the eye ground appears normal. For-
tunately, this is a rare disease and is usually found
among the aged. There is no relief for the condi-
tion and fortunately total blindness seldom occurs.
Amaurotic Family Idiocy, Symmetric Changes
at the Macula Lutea in Infancy. The infant is
usually of Hebrew parentage. A most unusual
disease and not many cases recorded. It was first
described by Warren Tay. The ophthalmoscopic
picture is one which resembles embolism of the cen-
tral artery. In this disease the macula lutea is
very conspicuous by being cherry red and of much
larger area than the red spot of embolism ; it is im-
mediately surrounded by an area of gray white-
ness about the size of the disc or a trifle larger.
The rest of the eye ground appears normal, all
except the disc, which soon becomes atrophic. As
its name indicates, it is a disease of infancy. The
infant seldom reaches its third year. Disease of
the brain and spinal cord accompany the eye condi-
tion. This disease is caused by an arrest of devel-
opment and changes are found in the ganglion
228 THE OPHTHALMOSCOPE.
cells of the retina, of the cortex, and degeneration
of the cord.
Purulent Retinitis. This, like purulent choroid-
itis, is due to septic emboli, and the two conditions
generally appear together. The ophthalmoscope
shows numerous hemorrhages and many white or
yellowish-white opaque spots, which soon become
diffuse and the vitreous becomes cloudy (see Puru-
lent Choroiditis).
Angioid Streaks. Pigment streaks in the retina.
This is a very rare condition affecting both retinas.
The vision is somewhat diminished. These streaks
are recognized as being in the deep layers of the
retina, as the retinal vessels are seen to pass over
them. The first impression is, that these streaks are
obliterated vessels which they resemble. They are
brownish in color, irregular in outline and not sym-
metric. There is no treatment.
CHAPTER IX.
DISEASES OF THE OPTIC NERVE.
DISEASES of the optic nerve are recognized by
the patient's symptoms, the field of vision, the
visual acuity and a study of the optic disc which
is the only part of the nerve that can be seen with
the ophthalmoscope. The study of the pathologic
disc therefore requires a knowledge and apprecia-
tion of the normal disc and an intimate acquaint-
ance with the anatomic construction of the part
and parts concerned (see Chapter III.). The
disc itself is nourished by the capillary branches
from the central and posterior ciliary arteries
which make up the circle of Haller. The central
vessels (except the capillaries just mentioned) on
the disc are terminal vessels and go to nourish the
retina. The transparent nerve fibers in their re-
spective bundles pass through the openings in the
membrana cribrosa ; these openings act like so many
collars around the nerve bundles, if therefore from
any cause these nerve fibers become swollen or in-
flamed, then the membrana cribrosa acts like liga-
tures and the resulting conditions as seen with the
ophthalmoscope must be in keeping with the degree
of swelling and constriction exerted.
Color of the Normal Disc. This has already
229
230 THE OPHTHALMOSCOPE.
been described in Chapter IV., but there is ample
room for dispute by the best authorities as to slight
changes from the normal complexion or what repre-
sents the normal color for a certain disc in a cer-
tain fundus, and frequently the surgeon must make
examinations on different days before committing
himself to an opinion that might otherwise be
erroneous.
Hyperemia of the Disc. The normal disc is
said to be pink or yellowish-red in color (Plate I.) ;
then if the disc appears red in color it is said to be
hyperemic; some authorities call this "peach red,"
" cinnabar red," " brick dust red," etc. If the
hyperemia is of moderate amount the edge of the
disc may be easily distinguished, but if the hyper-
emia is excessive or is increasing, the disc becomes
indistinct or possibly obscured, and the disc edges
cannot be definitely distinguished from the sur-
rounding eye ground except by following the ves-
sels to their central convergence.
Pallor of the Disc. This is a condition the very
reverse of hyperemia. The color of the disc in place
of being normal in color will appear chalky white,
as the very extreme condition of pallor. Slight
degrees of pallor are not readily distinguished,
and considerable practice is required for a positive
opinion, and frequently other conditions must be
taken into consideration before deciding positively.
Pallor of the disc due to anemia gives the rest of
the eye ground a pale appearance also, whereas
DEPRESSIONS OF DISC. 231
when the disc is chalky white in color, the surround-
ing eye ground appears redder than normal, and
this is brought about by contrast (Plate X.).
Changes or Alterations in the Surface Level
of the Disc, as compared with the adjacent eye
ground. The disc may appear level with the sur-
rounding eye ground or depressed in whole or in
part, or it may appear elevated.
Depressions. These may be classed as three,
the physiologic cupping, the glaucoma cup and the
depression from atrophy (saucer cupping). This
term 'saucer cupping' is really a misnomer, and
saucer excavation is a better one.
In the study of an elevation or depression of the
disc three methods may be followed: first, the ves-
sels are carefully studied in their course as they
adapt themselves to the surface on which they lie.
As an elevation or depression is a gradual ascent or
descent, then the course of the vessel will appear
gradually changed, whereas, if the elevation or de-
pression is abrupt the course of the vessel will appear
more or less sharply bent. If the alteration from
the level is gradual, then the vessel may be continu-
ously traced, but if the alteration from the level is
abrupt the vessel will have the appearance of being
broken, or it appears to stop abruptly and then to start
again at a different level (Plate XIL). Second, the
proof of the difference in level is made evident when
the observer has to employ a different strength lens
in the ophthalmoscope to see the vessel clearly in
232 THE OPHTHALMOSCOPE.
its different positions or levels ; for instance, a ves-
sel at the edge of the disc may be seen clearly with
a + 5 D. in the ophthalmoscope, and at the same
time the same vessel will appear hazy or indistinct
at the bottom of the cupping, and might require a
minus lens to bring it into view at that point. It is
much better to select small vessels for this test as
they usually lie closer to the surface, and at the
same time require a little more delicate focusing.
Third, the parallax test (Chapter IV.).
1. Physiologic Cupping (see Chapter IV.)-
Fig. 73, No. i, is a drawing of the disc, showing
physiologic cupping, and illustrates the manner in
which the vessels pass in and out of it, conveying
the idea of how the nerve level is depressed with
the cupping.
2. Depression from Glaucoma Cupping (Plate
XII. ). This cupping represents an excavation of
the entire nerve head or disc, and is produced by
intra-ocular pressure; in other words, the nerve
head is pressed backward into the scleral ring. The
edge of the cup is steep, precipitous and even over-
hanging. The disc varies in color in different
cases, and is therefore variously described as
greenish, gray, grayish-blue or white. The vessels
in the retina appear to stop suddenly as they pass
over the edge into the cup, and then may reappear
out of focus at the bottom of the cup. The arteries
are smaller in caliber and the veins are full and tor-
tuous, sometimes having the appearance of a string
DEPRESSION FROM GLAUCOMA CUPPING. 233
of beads. When the edge of the disc is clearly fo-
cused and the ophthalmoscope is tilted so that the re-
flected light passes across the disc, the bottom of the
cupping appears to have a different rate of move-
ment; this is called the glaucomatous parallax.
Plate XII. shows the apparent sudden termination
of the retinal vessel at the edge of the disc, and
also the same vessel dimly seen in the bottom of the
20
234 THE OPHTHALMOSCOPE.
cupping. Fig. 73, No. 3, is a section of a glaucoma-
tous cupping and shows the steep or overhanging
walls of the cup.
3. Depression of the Disc from Atrophy. This
form of depression, like the glaucomatous, extends
over or embraces the entire disc, but unlike the glau-
comatous, it is shallow and the depression is very
gradual from edge to center, not abrupt like a cup,
but gradual like a saucer ; hence it is spoken of as a
saucer excavation in contradistinction to the cup-
ping excavation. The vessels on the disc, there-
fore, do not stop abruptly and then reappear, but
pass gradually from the edge to the center. In the
early stage of atrophy, the arteries are small and the
veins are full, but in the late stage of atrophy (com-
plete) both arteries and veins are very much dimin-
ished in calibre and cannot be readily distinguished
from each other by the light streak, as in the normal
eye. The color of the disc in this last stage of
atrophy is white or chalky, sometimes spoken of as
bluish-white, or the color of skimmed milk. This
color extends to the edge of the disc. Plate X.
shows the white disc, and Fig. 73, No. 2, a section
illustrating the gradual saucer curve, or bow shape,
to the disc.
To summarize:
Physiologic Cupping Glaucoma Cupping
(Fig. 73, No. i). (Fig. 73, No. 3)-
I. Cupping is central or to tern- I. Cupping entire,
poral side. Shelving from
the side.
ELEVATION OF DISC. 235
Physiological Cupping. Glaucoma Cupping.
2. Cupping gradual or abrupt. 2. Cupping has abrupt edges.
3. Vessels normal. 3. Veins full, arteries small.
4. Parallax occasionally marked. 4. Parallax very marked.
5. Normal color of disc. 5. Gray or pearly white color of
disc.
A trap hie
(Fig. 73, No. 2).
1. Depression is entire.
2. Gradual sloping.
3. Arteries and veins indistinguishable.
4. No parallax.
5. Disc white in color.
Elevation of Disc, the Swollen Disc. This is
the very reverse of the three conditions just de-
scribed. This is spoken of as optic neuritis, papil-
litis, choked disc. Remembering the anatomy of
the parts, how the sheath of the optic nerve is con-
tinuous with the sclerotic coat, and between the
nerve and its sheath is the arachnoid space, how the
fibers of the nerve with artery or arteries and veins
passed through the membrana cribrosa, then any
portion of the nerve lying in front of the mem-
brana cribrosa, must become constricted by this
membrana cribrosa during inflammation of the
nerve fibers, and this therefore means a compres-
sion or squeezing of the disc, and hence its name
"choked disc," papillitis, or optic neuritis. If the
disc swells, it must project forward into the vitreous
and also laterally. The swelling of the disc, whether
due to pressure on the nerve fibers while in the
nerve sheath before entering the scleral openings,
or from obstruction to venous or arterial blood, or
236 THE OPHTHALMOSCOPE.
by infection or proliferation; no matter what the
cause, the condition is the same in all, viz., swelling.
The presence of the swollen or elevated nerve head
can be proven by the different strength lens re-
quired in the ophthalmoscope to see first the top of
the disc and then the edge of the disc or the sur-
rounding eye ground. The swollen nerve head is
composed of nerve fibers, inflammatory products,
contracted arteries and very full veins. The di-
ameter of the nerve head must therefore be much
greater than normal; three times its normal diam-
eter has been reported. The nerve fibers, as they
pass from the disc, are seen to be swollen for some
distance beyond its normal edge. They are opaque
and gray in color. The edge of the disc is no longer
clear cut but rather indefinite and merges gradu-
ally into the surrounding fundus. The margin of
the disc is spoken of as foggy, misty or woolly.
The veins are full and tortuous, as the return blood
from the retina cannot get out of the eye on account
of the swelling. The arteries on the disc and in
the retina are smaller for the same reason that the
veins cannot carry the blood from the eye, so the
arterial blood cannot get into the eye. The veins
are more or less covered by inflammatory products
and in some places they may be completely covered,
or here and there come into view but are rarely
seen distinctly. The arteries are often so small in
caliber as to appear like threads and are seen with
difficulty, or possibly cannot be seen at all. The
CONSTRICTION OF CIRCULATION.
swollen nerve head may be described or considered
in three stages, the stage of swelling or constriction
of the circulation ; stage of effusion ; stage of reso-
lution, or absorption and atrophy.
Stage of Swelling or Constriction of the Cir-
culation. The elevation or swelling, while it may
be, and often is, irregular, slopes gradually down-
ward from the center into the surrounding eye
ground and the blood vessels follow the same slopes.
The nerve fibers are swollen and more or less
opaque and give the nerve head a striated appear-
ance. The disc margin, if it can be seen, is very
indistinct or foggy, not definite or clear cut. The
color of the disc is variously described as " red-
dish-gray," " brick dust red," and even as violet
and bluish. The veins are dark or almost black in
color, full and tortuous. The arteries are small
and do not carry much blood. This is the first
stage of optic neuritis, or choked disc, or papillitis.
The height of the swelling is calculated by the
strength of lens in the ophthalmoscope required to
see the top or apex of the swelling, as compared
with the strength of lens required to see the sur-
rounding eye ground, each three diopters represent-
ing very closely one millimeter of elevation.
Stage of Effusion or Cell Proliferation. The
swelling of the disc is now quite regular, and the
striation is not nearly so well marked. The effusion
or exudation extends well beyond the disc margin,
giving a decided opaque appearance which blurs
238 THE OPHTHALMOSCOPE.
or obscures all fine detail observations. The central
vessels are more or less concealed by the effusion
and the arteries may not be seen. The color of
the disc is not now as red as in the first stage, but
is a dirty gray, and hemorrhages of varying sizes
and shapes may be seen on and around the disc, and
through the eye ground.
The Stage of Resolution or Absorption and
Atrophy. As the inflammation gradually subsides
the swelling diminishes and the effusion is very
slowly absorbed. The veins become less tortuous
and their color less dark. They also diminish in
caliber. The arteries remain thread-like and some
of them may not be seen at all. The color of the
disc is entirely white, or the color of chalk, and
may appear glistening. This is the declining or
final stage of optic neuritis. The surrounding eye
ground shows faint and irregular pigmentation;
this is often quite marked at the edge of the disc
(Plate IX.).
Optic Neuritis. There are several varieties of
neuritis named principally, from the anatomic parts
or part of the nerve involved.
Papillitis. Inflammation of that portion of the
nerve which is anterior to the membrana cribrosa,
or an inflammation of that portion of the nerve
which can be seen with the ophthalmoscope.
Papillo-retinitis. Papillitis associated with
retinitis.
Ascending Neuritis. This is an inflammation
PAPILLITIS. 239
which starts at the eye and extends or ascends
toward the brain. Descending Neuritis is the re-
verse of the ascending variety, the inflammation
starting in the brain or back of the eye and de-
scending toward the eye. An inflammation of the
nerve back of the eye, is spoken of as retro-bulbar
.neuritis. A partial neuritis is an inflammation of
a part and not the whole of the nerve.
Papillitis, also called Choked Disc, Neuritis,
Intra-ocular Optic Neuritis. This begins as a
hyperemia of the disc and passes into a stage of
swelling so that the disc projects into the vitreous
and its apex is seen with a different strength lens
than is required to see the surrounding eye ground.
According to Untoff, the elevation of the disc
should be about two-thirds of one millimeter before
it is spoken of as choked disc. The disc is also seen
to be two or three times its normal width. The
physiologic cupping, if previously present, is now
absent. Hemorrhages, few or many, may be seen
in and about the disc and occasionally throughout
the fundus. The arteries and veins are seen to
pass down from the apex or summit of the swollen
disc and to bend abruptly to the level of the sur-
rounding eye ground. The arteries are so crowded
or pressed upon that the blood cannot pass through
into the eye, and naturally they maintain more or
less of their straight course, and on account of the
same pressure the veins become full, swollen and
tortuous because the blood cannot get out of the
240 THE OPHTHALMOSCOPE.
eye and must remain backed up in the veins. The
veins get so full and tortuous as to appear like half
circles (-Plate III.) or serpentine, and hence the
name of "medusa nerve," given to the veins and
disc.
Papillitis usually appears in both eyes, but may
occur in one and when seen in one eye alone it may
be due to a local cause in the same orbit, and this
should be carefully looked for. If the cause is not
local then tumor of the brain may be diagnosed
with considerable certainty, and as being on the
side of the brain corresponding to the eye affected.
Papillitis, while so suggestive of brain tumor, does
not indicate the portion of the brain implicated.
Vision and Visual Field. In papillitis the cen-
tral vision may be normal at first, but later on may
become affected (see footnote, page 18). In
rare instances central vision may be lost sud-
denly. The field of vision is irregular in the
periphery and the blind spot is enlarged. Color
vision may be affected and hemianopsia may be
present, under certain conditions.
Course of Papillitis. As the retina is in great
part a continuation of the optic nerve, it is difficult
to imagine a case of papillitis without some involve-
ment of the retina, and it becomes quite doubtful
if papillitis can exist " per se." In cases of choked
disc that recover the inflammation gradually sub-
sides and atrophy supervenes. The swelling dimin-
ishes in the disc and retina, the hemorrhages are
CAUSES OF PAPILLITIS. 24!
absorbed without leaving any trace of their pres-
ence, unless quite large, when they occasionally
leave yellowish-white patches in the retina which
mark their previous existence. For a time the
veins and arteries may regain in great part their
normal positions and size, and may remain so if ex-
tensive atrophy does not follow. The disc may ap-
proximate the normal state also, but with irregular
edges and with scattered broken pigment massings.
This is an important part of the differential diagno-
sis between atrophy following choked disc (Plate
IX.) and atrophy following medullary or interstitial
neuritis (Plate X.) where the disc edges are clean
cut and well defined. Vision is usually very much
reduced and peripheral vision irregularly con-
tracted.
Causes of Papillitis. Of all the causes of papil-
litis by far the most common is tumor of the brain,
namely, gumma, sarcoma, fibroma, carcinoma, etc. ;
or to state the fact more definitely, no matter what
the size of the tumor in the brain may be, large or
small, or its variety or its location in the brain,
78 per cent, of cases of brain tumor develop papil-
litis as the most important symptom. The follow-
ing very interesting and instructive table "The
Papillitis Accompanying Brain Tumor," by John
E. Weeks, M.D., presented at the Section on Oph-
thalmology at the fiftieth annual meeting of the
American Medical Association held at Columbus,
Ohio, June 6 to 9, 1899, gives the percentages of
242
THE OPHTHALMOSCOPE.
choked discs, resulting from tumor in the brain
and the locations of the tumors, etc.
Location.
6
K
~
o : |
c z
**
Unilateral.
Double
Optic
Neuritis.
Per Cent.
Frontal lobes
64
12
4
48
80.7
Temporo-sphenoidal
24
9
O
1C
62.5
Motor area
m
46
7
64
SQ. 2
Parieto-occipital
77
4
7
26
87.8
Brain surface
17
4
O
60.2
Centrum ovale
58
17
2
TO
70.7
Corpora quadrigemina
10
o
o
IQ
IOO
Basal ganglia
36
1C
O
22
61.1
Multiple
jq
II
2
26
46.6
Corpus callosum
12
7
O
41.7
Pituitary body
18
O
SO
Pineal gland
i
I
o
o
O
Crura
c
I
o
4
80
Pons
So
20
c
2?
60
Cerebellum
164
21
170
87.2
Base of cranium
IO
I
o
oo
IO
II
8^.7
Totals
677
1 80
27
470
69.4
Among other causes of choked disc or papillitis
may be mentioned meningitis in any of its varieties,
especially the tubercular, occurring among children
as a rather frequent cause. The following have
been noted as causing papillitis, albuminuria, dia-
betes, rheumatism, brain abscess, hydrocephalus,
thrombosis of the cavernous sinus, acromegaly
(swollen pituitary body), aneurism, cysts, hemor-
rhage of the meninges and traumas. Papillitis has
been noted during typhoid fever, scarlet fever, diph-
theria, small-pox, erysipelas, syphilis, influenza, etc.
Sunstroke, disturbances of menstruation, lead and
TREATMENT OF PAPILLITIS. 243
alcohol have also been recorded as causes, showing
that the causes of papillitis are very many and vari-
ous, and yet cases occur idiopathically.
Prognosis. No matter what the cause of the
papillitis, the prognosis must always be grave, for
the simple reason that the vision is always more or
less damaged, the one exception to this statement
being the toxic amblyopias, which may recover,
otherwise the underlying cause of the papillitis
(tumor of the brain, etc.) places the patient's life
in danger.
Treatment. The cause must be carefully sought
for and carefully treated. Patients having pap-
illitis due to syphilis must be brought promptly
under the influence of mercury and as soon as
this is accomplished iodids should be pushed
to iodism. Menstrual disorders should be cor-
rected when they are the underlying cause.
The alterative action of mercury and the iodids
is appropriate treatment in almost every in-
stance, with the exception of the tubercular.
When the papillitis is due to a growth the case
should have the opinion of a neurologist and
surgeon.
Neuro-retinitis, or Papillo-retinitis (Plate V.).
With swelling of the disc as described under Papil-
litis, the retina usually becomes involved and as this
membrane becomes swollen and opaque the retinal
vessels become more or less hidden in the swelling
and resulting exudates. Hemorrhages make their
244 THE OPHTHALMOSCOPE.
appearance in the course of the vessels and have
flame-shaped edges as they lie in the nerve fiber
layer. Large and scattered areas of exudate make
their appearance, and also an irregular star-shaped
figure at the macula, not unlike the condition seen
in albuminuric retinitis.
The differential diagnosis between papillitis per se
or neuro-retinitis due to brain tumor and albumin-
uric retinitis is not always easy, and must be very
carefully studied before coming to a positive diag-
nosis. The addition of palsies of any of the ocular
muscles would strongly suggest a growth in the
brain while the absence of palsies and the presence
of albumen and casts in the urine would indicate
nephritis, though both conditions have been known
to exist in the same patient.
Retrobulbar Neuritis Acute and Chronic,
Medullary Neuritis, Interstitial Neuritis. This is
an inflammation of the optic nerve back of the eye-
ball and within the orbit, therefore anterior to the
optic foramen.
Acute Retrobulbar Neuritis. Early in the dis-
ease there are few ophthalmoscopic changes noted,
and when they do appear they are slight and may
be overlooked, viz., hyperemia of the disc with its
edges hazy. The diagnosis is made primarily from
rapidly failing vision (central) \vhich brings the
patient under observation; in such instances this
failure of vision may result in almost complete
blindness in a few days.
CHRONIC RETROBUL13AR NEURITIS. 245
Causes. Syphilis (gumma) ; taking cold; rheu-
matism; methyl alcohol; quinin; autotoxemia; dis-
turbed menstruation ; diabetes ; periostitis ; injuries.
In some instances no cause can be found. In other
cases it may be caused by decayed teeth, growths,
pressure, ethmoiditis, etc.
Prognosis. This must be very guarded, though
many cases recover; yet some few do not. For-
tunately it is often a unilateral disease.
Treatment. This is the treatment of the cause.
Chronic Retrobulbar Neuritis, Tobacco Am-
blyopia, Toxic Amblyopia. Patients complain
of poor vision for near work which cannot be
materially improved with any glass, and state
that vision is apparently better on a dull or
cloudy day and is worse when the sun shines
brightly. The ophthalmoscope reveals almost a
normal fundus, unless the case is well advanced,
when the disc may appear pale in whole or in part.
The field chart may be quite normal for form,
but central scotoma for red and green is present;
this scotoma is usually the same in both eyes, hori-
zontally oval and extends from and including the
normal blind spot to the macula, showing the in-
fluence of the disease on what is known as the pap-
illomacular fibers, the nerve fibers passing from the
disc to the macula.
Causes. As its name implies (tobacco ambly-
opia, blunted sight from tobacco) this chronic
retrobulbar neuritis is frequently caused by over-
246 THE OPHTHALMOSCOPE.
use of tobacco and very often this habit is associ-
ated with some moderate or excessive use of alcohol
in some form. The writer might state that there
is no rule or guide as to just how much smoking or
drinking will produce toxic amblyopia " What is
food for one is poison for another." Some men
can drink and smoke excessively and never develop
amblyopia, whereas another may develop ambly-
opia from only a moderate use of these toxic agents.
Tobacco amblyopia seldom develops before the age
of forty. Other substances that will produce the
same symptoms are essence of ginger, strong coffee
to excess, chloroform, opium, chloral, arsenic, iodo-
form, quinin, salicylic acid, acetanilid, caffein, bi-
sulphid of carbon, nitro-benzol, methyl alcohol
(wood alcohol), etc.
Prognosis. Favorable if due to alcohol and to-
bacco and the patient comes under observation early
and carries out the treatment. The prognosis must
be guarded in any instance and when due to causes
other than tobacco and alcohol the history of the
patient must have careful consideration.
Treatment. Stop the cause if possible. Pilo-
carpin sweats occasionally; strychnia in tonic doses
and the use of iodid of potash as an absorbent.
The patient must also be cautioned against return-
ing to the use of the drug or any drug which might
bring back a recurrence of the nerve condition.
Optic Nerve Atrophy. There is no portion of
the optic nerve exempt from this condition of
PLATE IX.
ATROPHY OF THE OPTIC NERVE (Posr PAPILLITIC ATROPHY). ALSO
MEDULLARY NERVE-FIBERS. FUNDUS OF RIGHT EYE.
DIRECT METHOD.
Miss L. D. Aged 16 years.
History. Patient was treated for " Choked Disc " in 1901. Had
a tumor (gumma ( ?) ) of the brain. Patient treated by Drs. Mus-
ser, Spiller and Hermance.
Fundus Changes. Disc is bluish in color. The edges are not
well defined. Lamina cribrosa is not present. As a coincidence
there are medullary nerve-fibers present at the upper edge of the
disc. The whole fundus is peculiarly mottled (map-like). The
retina is atrophied and the macula cannot be distinguished. Arte-
ries are straight and some of the larger veins slightly tortuous.
Left eye similarly affected, but without the medullary fibers and not
such an extensive atrophy.
March 31, 1905. Vision of right eye with -f- i.oo Cyl. axis 100
degrees = light perception.
Vision of left eye with -f- i.oo Cyl. axis 80 degrees = VI/X.
248
PLATE IX
Atrophy of the Optic Nerve
(Past Papillitic Atrophy)
Also. Medullated Nerve-fibers
PLATE X.
PRIMARY OPTIC ATROPHY. (SPINAL ATROPHY.) FUNDUS OF RIGHT
EYE. DIRECT METHOD. FUNDUS OF LEFT EYE
ABOUT THE SAME.
Mr. William S. S. Aged 54 years. Dyer by occupation.
History. Vision has been failing gradually for two years. Has
been using various glasses to read with and now cannot read with any
glasses that he can purchase. His walk has been impaired for about
the same length of time that his sight has been failing him. His-
tory of syphilis. Uses tobacco and alcohol to excess.
Irises do not react to light stimulus, but do respond to conver-
gence and accommodation (Argyll-Robertson Pupils).
Fundus Changes. Vision of each eye about i/io. Disc bluish in
color and glistening. Membrana cribrosa is seen at the center of
the disc. The disc has a white edge, called by some a scleral ring.
A cilio-retinal vessel is seen on the temporal edge of disc passing
toward the macula. Fundus reflex apparently normal. Vessels arc
not particularly narrowed at the present time. Arteriosclerosis evi-
dent at crossing of vessels. Disc has " saucer " shaped excavation.
252
PLATE X
Primary Optic Atrophy
PRIMARY ATROPHY. 255
shrinking of its elements from the brain center up
to and including the papilla. There are three dis-
tinct forms of atrophy, primary, secondary and
consecutive.
Primary Atrophy. Spoken of as progressive,
degenerative, gray, spinal or tabetic atrophy (Plate
X.). This is an atrophy that appears without any
apparent or very slight previous inflammation. It
is usually bilateral. It may be a local condition of
one eye, but it is usually met with in locomotor
ataxia and disseminated sclerosis, therefore affect-
ing both eyes. Spinal disease (33 per cent.) is
the most common cause of gray degeneration of the
optic nerve, especially in locomotor ataxia. Among
other causes are, malnutrition, taking cold, dis-
turbed menstruation, syphilis, drugs, etc. ; and occa-
sionally the cause may be unknown. Hereditary
predisposition; this latter variety, if it may be so
called, has been known to appear in the male mem-
bers of a family generation after generation, and
to develop about the age of twenty-one years.
Secondary Atrophy. This means that the nerve
has degenerated by reason of some previous lesion,
such as fracture of the optic foramen, pressure on
the optic tract, etc., or a disease of the nerve or
retina, embolism of the central artery of the retina,
retinitis pigmentosa, retino-choroiditis, syphilitic
retinitis, glaucoma, etc.
Consecutive Atrophy. Also spoken of as post-
neuritic atrophy or post-papillitic atrophy. This is
256 THE OPHTHALMOSCOPE.
the variety of wasting that follows an inflammation
like papillitis (Plate IX.). The terms secondary
and consecutive atrophy are often confused.
Ophthalmoscopic Appearances. To study the
different varieties of atrophy, it is well to employ
both the direct and the indirect methods. The two
principal characteristics of atrophy as seen with
the ophthalmoscope are paleness or whiteness
of the disc and a diminution in the vascularity.
The disc (principally the intermediate zone)
loses its normal pink or yellowish red color and
appears pale. It is the capillary circulation that
produces the shell pink color of the normal healthy
disc, and when this circulation is destroyed atrophy
must be present. It is not absolutely necessary to
have the large vessels of the disc diminished in
size to have atrophy, and sometimes the large ves-
sels do not perceptibly diminish in size until late in
the disease. It may also be stated that occasionally
the large vessels may diminish in size and atrophy
develop before the capillary circulation disappears
or lessens. The color of the disc in atrophy is not
the same in all eyes, and has been described as
white, chalky white, snow white, cottony white,
pearly white, gray, grayish-white, bluish, skim milk,
green, etc. These colorings are controlled in great
degree by (a) the reflected light, its quality, color
and intensity; (b) by the comparative color of the
surrounding eye ground; (c) by the presence or
absence of the physiologic or glaucoma cupping;
OPHTHALMOSCOPIC APPEARANCES. 257
(d) by the membrana cribrosa, if present or ab-
sent; and also (e) by the character of the inflam-
mation previous to the atrophy. The colorings of
the nerve in atrophy cannot be attributed to pig-
mentation. Of course the observer's idea of color
must also enter into the description of the color of
the atrophic disc. The color of the atrophic disc is
not always uniform; the center may be stippled
white and gray, and the edge have a gray or green-
ish or bluish tinge (Plate X.), and so there are in-
numerable variations.
Causes. Most cases of locomotor ataxia are ac-
companied sooner or later by primary optic atrophy
and in fact optic atrophy may be a preataxic symp-
tom. Multiple sclerosis is another cause of pri-
mary optic atrophy, as also epilepsy and progressive
paralysis (see page 255).
Differential Diagnosis. Atrophy following
papillitis and primary atrophy are not the same in
all particulars, though they have many points of
similarity.
Primary Atrophy Atrophy from Papillitis
(Plate X.). (Plate IX.).
Disc very brilliant and glistening White color of disc, not bril-
white pearly white, or gray. liant; appears a dirty gray,
described as bluish.
Disc edges sharply cut. Disc edges not usually well de-
fined.
Lamina cribrosa very conspicu- Lamina cribrosa usually not con-
ous. spicuous.
Arteries and veins not so con- Arteries and veins very narrow ;
tracted. veins tortuous.
Excavation, if present, is saucer
shaped.
258 THE OPHTHALMOSCOPE.
Diagnosis of Optic Atrophy. The ophthalmo-
scopic findings make the diagnosis quite easy when
the disease is well advanced, but if the disc has not
become decidedly pale, then other symptoms must
have careful consideration. The central vision may
remain good for quite a while whereas peripheral
vision may be concentrically contracted, the color
fields contracted and central scotoma evident. The
history of the patient is also of considerable im-
portance.
Prognosis. Unfavorable. The condition leads
to blindness in most instances. Of course the prog-
nosis must be controlled by the underlying cause.
Syphilitic cases appearing early give a fair prog-
nosis. In cases of locomotor ataxia, the atrophy
advances and blindness eventually takes place.
Treatment. This depends upon the cause. If
syphilis is suspected then mercury and iodids should
be prescribed and pushed to the point of tolerance.
When due to other causes, nerve stimulants,
strychnia by mouth and hypodermically, nitro-
glycerin, phosphorus, iron, etc., may be prescribed
as indicated and galvanism may be tried.
CHAPTER X.
DISEASES OF THE CHOROID. GLAUCOMA.
DISEASES of the choroid, like diseases of the
retina and optic nerve, give defective vision as the
most important symptom to the patient, without any
external manifestations of the inward changes. It
is unfortunate for the patient that these structures
are not supplied with nerves of painful sensation
like the iris and ciliary body, so that the patient
would come under observation much sooner and
before serious damage to vision has resulted. Dis-
eases of the choroidal coat of the eye are indicated
with the ophthalmoscope by many changes from the
normal appearance of this tunic, namely:
1. Changes in the color of the eye ground.
2. Inflammatory products, patches of exudation,
and changes in elevation.
3. Changes in pigmentation.
4. Areas or white patches of exposed sclerotic
resulting from absorption of choroid and retinal
tissue.
Changes in Color. A diagnosis of hyperemia
of the choroid or disturbed choroid is not easily
made by the beginner in ophthalmoscopy, and it is
not until an infiltration has taken place which gives
the previously red reflex a yellowish tinge, that the
2 59
26O THE OPHTHALMOSCOPE.
inflammation of the choroid is definitely recognized.
Fortunately, from a diagnostic point of view, in-
flammation of the choroid does not occur in the
whole choroid at one and the same time, but is seen
in scattered areas.
Inflammatory Products. Areas of exudation
may appear round or oval or irregular in form,
but they are usually oval in outline. These spots or
areas being pale yellow in color, are to be distin-
guished from an opaque or foggy retina. Patches
of recent choroiditis, while elevated are at a greater
depth, and at some few, or many points retinal
vessels may be seen passing over them, and they
are therefore elevated on these patches. Opacities
are sometimes seen floating in the vitreous, appear-
ing like dust particles, or threads.
Changes in Pigmentation. Another decided
characteristic of inflammation in the choroid is
the change in its pigmentation at and around the
spot of inflammation, and the retinal vessels are
often seen passing over these inflamed areas
which of course include the pigmentation if
the disease is advanced. The pigmentation is
never uniform, but is usually quite irregular,
sometimes rounded, sometimes crescentic; it is
brown or black in color giving the fundus the ap-
pearance of having had blots of ink scattered over
it. The number and character of these black spots
is usually in keeping with the number and size
of the areas of inflammation. Pigmentation is usu-
ATROPHY. 26l
ally a late manifestation of an area of choroiditis.
Areas of choroiditis may be seen in various stages
of inflammation in the same eye ground. New
areas appear while others have reached the atrophic
stage.
Atrophy. This condition of the choroid natur-
ally follows absorption of the exudates at the areas
of inflammation, and is indicated by white areas
of irregular shape with scattered pigment at the
edges. Spots of atrophy (exposed sclera) stand
out in bold relief. It is not unusual to see a few
choroidal vessels passing through atrophic areas.
Hemorrhage of the Choroid, while it may take
place, and no doubt often does occur (when the
extensive vascularity of the choroid is taken into
consideration), yet hemorrhage of the choroid is
not easily recognized with the ophthalmoscope, as
the retinal layers hide them unless they are large
and very extensive, when they may break through
into the deep layers of the retina, or even into the
vitreous.
Inflammation of the Choroid (choroiditis) is
a very indefinite name unless qualified, so as to give
the variety and if possible the cause of the inflam-
mation. Furthermore, choroiditis has come to
mean not only an active inflammatory state, but a
condition of the choroid after the inflammation has
subsided. Choroiditis is said to be the most com-
mon of fundus diseases and only too frequently
it damages or destroys the sight.
262 THE OPHTHALMOSCOPE.
The varieties of choroiditis are innumerable, and
have been variously classed, but each variety pre-
sents one or more of the characteristics just de-
scribed. Superficial and deep choroiditis are so
called on account of the part of the choroid af-
fected. The terms acute and chronic are self-
explanatory, and disseminated means that there
are several or many points or spots of inflammation
scattered through the choroid (Plate XL). If one
large area of the choroid is alone involved this is
called diffuse. Diffuse choroiditis (also called
deep choroiditis) may result from several dissemi-
nated areas enlarging and coming together. Cir-
cumscribed choroiditis means an inflammation
more or less limited in extent, whereas macular or
central choroiditis, while it may be circumscribed,
means an inflammation at the macular region.
Senile choroiditis, as its name indicates, is choroid-
itis in the aged and is usually a variety of central
or macular choroiditis. Recent and old choroiditis
are other names given to the acute and chronic
varieties, and atrophic choroiditis is but the final
stage of the disease. Myopic or posterior choroid-
itis is usually a choroiditis seen in eyes which have
a high myopic refraction, and, as its name implies,
is in the posterior part of the eye and usually
begins at the temporal side or edge of the disc,
and is called the myopic crescent from its fre-
quent resemblance to a crescent; or, if the cho-
roiditis surrounds the disc, it is called annular,
PLATE XI.
RETINO-CHOROIDITIS (SPECIFIC). FUNDUS OF LEFT EYE. DIRECT
METHOD.
Mr. E. Aged 39 years.
History. Failing vision was noticed three days before coming
under observation. Thought it was only a cold in his eye, as he
had iritis and cyclitis as complications.
Fundus Changes. Nasal edge of disc hidden and cannot be dis-
tinguished from the neighboring retina. Temporal edge of disc is
clear and reveals a narrow crescent. A few yellowish-colored spots
seen in the choroid. Other spots of choroiditis have become absorbed
and white areas (atrophy) have taken their places with irregular pig-
mentations. The choroidal circulation is exposed in the periphery.
A large patch of retino-choroiditis is seen close to the temporal side
of the disc. Vision is very much reduced and the patient depends
on the vision of the right eye, which is VI/IX and was not so
seriously disturbed.
264
PLATE XI
Retina- Charm ditis
DISSEMINATED CHOROIDITIS. 267
and if there is any bulging backward of the sclerotic
coat, it is called a posterior staphyloma. Syphilitic
choroiditis is named from its cause and may mean
any one of the varieties mentioned, though the dif-
fuse or circumscribed variety is usually understood.
Disseminated Choroiditis (Plate XL). This
is recognized as the most common form of choroid-
itis. The spots of inflammation are scattered (dis-
seminated) over the eye ground chiefly in the
periphery. These areas are at first yellowish in
color, slightly elevated, more or less oval in shape.
As these inflammatory exudates become absorbed
the choroidal tissue is also absorbed or destroyed,
the white sclera showing in its place, and pigment
massings surround many of the irregular areas.
These areas of absorption have the appearance as
if parts of the choroid had been punched out by an
instrument which was not clean, and therefore had
left black edges. In other instances, or even in the
same choroid, the exudates may be replaced by a
large spot of pigment, or possibly by several spots
which may coalesce, forming one large, or several
large, patches. In some instances irregular figures
may be depicted. The choroid between the patches
is seen to be apparently healthy. The optic disc is
seen to be atrophic in the late stages of severe cho-
roiditis, and the term secondary optic atrophy has
been given to this condition. Both eyes are usually
affected, often one eye being affected in advance
of its fellow.
268 THE OPHTHALMOSCOPE.
Causes. Syphilis is recognized to be the most
common cause of this disease whether acquired or
inherited. Other causes may be looked for in gen-
eral diseases, scrofula, anemia, chlorosis and also
in myopia. Sometimes the cause cannot be de-
termined.
Symptoms. These are principally those of de-
fective vision and as the retina and vitreous are
implicated the descriptions of the patient are in-
dicative of the structure or structures involved.
Floating specks indicate vitreous opacities, and
distortion of objects (metamorphopsia) when
the edge of a door frame or a straight line ap-
pears bent, indicates that the retinal elements
are separated or crowded together by being
raised up by an exudate. Central and peripheral
vision are impaired according to the amount
of structure disturbed and also its location in
the fundus. Scotomata are quite in evidence, but
not so annoying when in the periphery as when
they crowd upon the macular region.
Course of Choroiditis. This is usually a chronic
condition, taking many weeks or months for the
exudates to be absorbed. Atrophy of the retina
and the disc are liable to eventually make the case
worse, especially if the choroiditis has been exten-
sive. Cataract is not an infrequent complication
late in the disease.
Prognosis. This depends ( i ) on the portion of
the choroid involved, (2) on the extent of the in-
TREATMENT OF CHOROIDITIS. 269
flammation, and (3) on the cause of the choroid-
itis. If the periphery of the choroid alone is in-
volved, central vision may remain good, but if the
inflammation involves the macula or its vicinity,
the prognosis for useful vision must be guarded.
When caused by syphilis, and the patient is seen
early and placed under prompt and vigorous anti-
syphilitic treatment, the case will be quite favorable
for useful vision if the macula has not been in-
volved.
Treatment. If caused by syphilis this must be
treated energetically with mercurial inunctions,
large and increasing doses of the iodids, pilocar-
pin sweats, etc. If the choroiditis is caused by
anything else, it must be treated according to its
cause. It is a noteworthy fact that no matter what
the cause, the alernative treatment with mercury
and the iodids is often the best treatment. This
should be borne in mind, as valuable time might be
lost if the physician was not on his guard in finding
the cause, or not disposed to believe that the indi-
vidual could be subject to syphilis.
Aside from the systemic treatment the eyes
should be protected from bright lights with dark
glasses, and the accommodation put at rest with a
properly selected cycloplegic.
Diffuse Choroiditis. (Also called deep and
exudative choroiditis.) This is practically a sub-
division of the disseminated variety. The ophthal-
moscope reveals large areas of yellowish-white
270 THE OPHTHALMOSCOPE.
exudates ; these may be scattered or they may coal-
esce. If the retina becomes involved, as it often
does by contiguity of structure, the condition is
one of choroido-retinitis, and the opaque retina
adds its quota to the characteristic picture. In this
condition of choroido-retinitis pigment may be seen
here and there upon the retinal vessels. When ab-
sorption or atrophy of the yellowish areas takes
place, the sclera becomes exposed in large or small
areas with irregular patches of pigment at the
edges, or irregularly scattered. Often they assume
an oval or circumscribed appearance.
Course, prognosis and treatment are the same
for diffuse choroiditis as for the disseminated
choroiditis.
Central Choroiditis. (Also called macular or
senile.) This is usually a condition of both eyes.
As it involves the macular region the vision is usu-
ally seriously diminished, with resulting scotoma.
The disease is recognized in several varieties ; there
may be an atrophic patch with surrounding pig-
ment at the macula, or there may be a large white
area at the macula in which choroidal vessels may
be seen. Another variety is known as " Tay's
choroiditis" or " Tay's dots"; these are many
small, white, glistening dots (called senile guttate
choroiditis), and are due to colloid degeneration.
Causes. Trauma and syphilis and ametropia are
the commonly recognized causes. Senile choroid-
itis does not appear to be benefited by treatment.
MYOPIC CHOROIDITIS. 2/1
When caused by syphilis and ametropia the treat-
ment is self-evident.
Myopic Choroiditis. Usually this is a very
serious condition, and means that the condition
has been brought about by a stretching or elonga-
tion of the eyeball and as its name indicated the
eye is myopic. The choroiditis begins usually or
almost invariably on the temporal side of the disc
and advances toward the macula and may destroy
it and pass beyond. The choroiditis may encircle
the disc at the same time. The choroidal vessels
become exposed, the retina atrophies and the pig-
ment becomes scattered irregularly. Vitreous
opacities are innumerable and of various sizes and
forms, the vitreous itself becoming quite fluid.
The vision is very much reduced and detachment
of the retina and the development of cataract may
soon complicate the already " sick " eye. The
treatment resolves itself into rest of the eye for all
near work, protection from bright lights, and care-
ful attention to the general health and later to
the correction of the refractive error with careful
instructions to the patient to use his eyes as little
as possible. Internally alterative treatment occa-
sionally does much good.
Colloid degeneration of the choroid, also called
guttate choroiditis, is an extremely rare condition
and is recognized as occurring in the macular
region. The ophthalmoscope reveals many round
elevated spots or bodies, placed close together, they
2J 2 THE OPHTHALMOSCOPE.
are semi-transparent, and have been compared by
their resemblance to a mulberry. It is a condi-
tion of both eyes, but one of the eyes may be
more involved than its fellow. The vision is
often impaired. There is no treatment for the
condition other than prescribing the necessary
glasses.
Irido-choroiditis (also called panophthalmitis,
metastatic, purulent or suppurative choroiditis) is
an acute inflammation of the choroid pursuing a
rapid course, and caused by purulent matter being
carried into the choroid. No satisfactory study of
the choroid can be made out unless the disease
comes under observation quite early and yields
to prompt treatment. The areas of purulent exu-
date seen in the choroid soon coalesce and at the
same time the retina and vitreous become involved.
With a strongly reflected light a large yellowish
mass may be seen in the vitreous, and no clear view
of the fundus is made out. Iritis, cyclitis, etc., are
early manifestations which go to make up the true
picture of panophthalmitis. External manifesta-
tions of panophthalmitis are swollen lids, the con-
junctiva edematous and possibly protruding
between the lids, the cornea appearing to be buried
in the swollen conjunctiva. The patient complains
of pain and loss of sight, and the temperature is
elevated.
Causes. Purulent matter carried into the eye
by the blood vessels or germs entering the eyeball
RUPTURE OF CHOROID. 273
from perforating wounds or ulcers. Puerperal
sepsis ; meningitis ; small-pox, etc.
Prognosis. This must be very guarded. Either
blindness with shrinking of the globe (phthisis
bulbi) or enucleation will be the usual and final
result of panophthalmitis.
Treatment. Careful attention to local and con-
stitutional symptoms. Atropin instillations, cold
compresses medicated with bichlorid of mercury
1-2,000, blood-letting from the temple, enucleation,
if there is not much hope of saving the eye by rea-
son of pain (glaucoma), pus in the anterior cham-
ber, and orbital cellulitis or cerebral meningitis
threatening.
Rupture of the Choroid. This usually takes
place as a result of a blow on the eye and is recog-
nized by a tear or rent in the choroid, resembling
in shape a new moon; the hollow or concavity of
the crescent with irregularly pigmented edges is
toward the disc, the crescent itself is yellowish-
white, this color resulting from a partial exposure
of the sclera. The common location of the rup-
ture is to the temporal side of the disc. If the
retina was not injured, or only partly so, at the
time the choroid was ruptured, some of the retinal
vessels may be seen passing over the crescent. At
the time of rupture or soon afterwards the rupture
may be covered with a hemorrhage, and hence
the picture just described cannot be definitely
studied with the ophthalmoscope until after ab-
2/4 THE OPHTHALMOSCOPE.
sorption of the clot. The rupture may lie close to
or at some distance from, the disc, depending on the
character of the injury. The vision may be seri-
ously impaired if the rupture is at, or close to, the
macula.
Treatment. Cold compresses and a cycloplegic
if seen early. The injury is permanent and the
vision is disturbed accordingly.
Sarcoma of the Choroid. When seen with
the ophthalmoscope there is an elevation of the
retina and the growth beneath appears brownish
or black, or white in color ; it is a melino-sarcoma if
dark in color and a leuco-sarcoma if white. Melino-
sarcoma is much more common, the leuco-sarcoma
being very rare. This growth is usually situated to
the temporal side of the disc and may appear as far
forward as the ciliary body. The detached retina
if seen when the sarcoma is small, is applied equally
to the surface of the growth and does not tremble
or have the characteristic wave motion that is im-
parted to the retina when the eye is rotated and
there is fluid beneath the retina (see Detachment
of the Retina). Sarcoma of the choriod is a rare
disease, most unusual in children and usually oc-
curs in adults past forty years of age.
Symptoms. The patient notices a defect in
vision which the ophthalmoscope usually reveals
as detachment of the retina. This is one of the
first indications of the disease. As the sarcoma de-
velops there is an increase in the size of the detach-
TUBERCULOSIS OF CHOROID. 275
ment and an increase in the tension together with
pain (glaucoma absolutum). The sarcoma may or
may not break through the sclera, but other organs
of the body, especially the liver, may suffer by
metastasis.
Prognosis. Most unfavorable. The eye must
be enucleated at once but this is no guarantee that
metastasis has not already taken place.
Treatment. Prompt enucleation and dividing
the nerve as far back as possible. If the orbital
tissue is involved this must be removed, including
the periosteum if necessary and following this later
with the employment of the X-rays.
Tuberculosis of the Choroid. This occurs either
as the disseminated (miliary) tubercle or as a soli-
tary (conglobate) tubercle. The former appears
as small round elevated spots of a pale red color
and grow rapidly. They appear in subjects who
have acute miliary tuberculosis, and are not often
seen in chronic tuberculosis. Solitary tubercle ap-
pears as a large mass which is virtually an accumu-
lation of many small nodules. This is a disease of
young subjects. The prognosis is very unfavor-
able for the eye and the patient. The treatment re-
solves itself into the systemic treatment of the pa-
tient and enucleation of the eye.
Glaucoma (yXavKo?, sea green).
A disease of the eye, so-called originally on
account of a greenish reflex occasionally ob-
276 THE OPHTHALMOSCOPE.
tained from the pupillary area. A very bad
name, therefore, as it does not explain anything
about the disease, and in fact a greenish pupillary
reflex may be seen in certain conditions of the lens
and not necessarily in glaucomatous eyes. Glau-
coma, as now universally understood from one of
its chief signs, is a disease characterized by an in-
crease in the intra-ocular contents, and this is
spoken of and known as " tension."
Causes. The causes of increase in the intra-
ocular contents is either hypersection of the intra-
ocular fluids or a blocking or stoppage of the ex-
cretory passages, or both conditions together. Just
which of these causes precipitates the attack can-
not always be determined in each instance, but
there is hardly any doubt but that secretion is go-
ing on while the excretory passages are blocked,
and this explains many of the other symptoms of
the disease.
The lymph stream of the eye flows from the
vitreous through the zonula of Zinn into the pos-
terior chamber, through the pupil into the anterior
chamber, and hence into the angle of the anterior
chamber, into the canals of Fontana and the canal
of Schlemm, then into the lymph channels exter-
nally. Any obstruction to the onward flow of this
stream, means pressure of the intra-ocular contents
against the sensitive nerves and the rigid outer
tunic of the eye, with resulting symptoms.
Inspection shows the vessels of the ocular con-
PLATE XII.
GLAUCOMA. FUNDUS OF LEFT EYE. DIRECT METHOD.
W. W. D. Aged 40 years. Salesman.
History. Vision of left eye was never as good as that ftf the
right. Has always worn glasses for " farsightedness." Never any
severe pain in left eye, and only lately has noticed that the vision
was getting much worse and the eye deviating outward.
Vision of left eye equals, seeing very large objects, or counting
fingers at about twelve inches distant. Eccentric fixation (periph-
eral vision).
Fundus Changes. Edge of disc seen with -f 6 D. and the bottom
of the cup is seen with a 5 D. Vessels of the retina disappear as
they pass into and around the edge of the disc, and are out of focus
when they reach the bottom of the cup, where they appear indis-
tinctly at the nasal side. The nerve is bluish or pearly white in
color and atrophic (glaucoma atrophy). The edges of the disc have
a distinctly yellowish color and the pigment is broken into fine par-
ticles. There is a peculiar redness showing at the macula. .
The cupping embraces the entire disc.
Right eye vision equals VI/VI with -|- 5 D. Glaucoma not
present.
278
PLATE XII
Glaucoma
SYMPTOMS. 28l
junctiva tortuous, appearing like fine corkscrews.
The cornea becomes cloudy, appearing like a piece
of glass that has been breathed upon, and is more or
less anesthetic. The anterior chamber is shallow,
the iris appearing nearer to the cornea than in
health. The pupil is dilated. The cornea being
cloudy and the large pupil being black the observer
may obtain at times and in certain lights a greenish
reflex from the pupillary area.
Subjective Symptoms. Pain in the eyeball
which may extend to the forehead, corresponding
to the eye involved, and also to the cheek bone and
same side of the nose, if the attack is unusually se-
vere. There is more or less dimness of vision de-
pending also upon the severity of the attack and
the dimness of vision may be particularly marked
in the nasal field. The patient notices halos (rings
of various colors) about any light.
Objective Symptoms. The tension of the eye-
ball is harder than normal. The beginner will ap-
preciate this by testing the tension of his own nor-
mal eye, by alternately pressing the ends of his
index fingers on his own eye through the upper lid
as the closed eye is directed downward, and then
testing the tension of the patient's eye in like man-
ner; or alternately testing the patient's eyes, as it
is not customary to find both eyes of the patient
exactly the same or equally affected, at the same
time.
Ophthalmoscopic Changes (Plate XII.). If
23
282 THE OPHTHALMOSCOPE.
the media are not too cloudy the observer will see
1 i ) the disc excavated or cupped, this cupping ex-
tending to the edge of the disc and the edges being
quite abrupt or overhanging, and the disc edges sur-
rounded by a yellowish halo or glaucomatous ring;
(2) the vessels in the retina as they are traced to the
edge of the disc (cup) bend at right angles, and if
seen at the bottom of the cup, are crowded more or
less to the nasal side and are no longer in focus as
compared with the strength of lens required to see
the vessels as they appeared at the edge of the disc ;
(3) the arteries are seen to pulsate at the edge of
the cup.
Diagnosis. Hazy cornea; and also anesthesia
of the cornea ; this latter is proven by touching the
cornea with a small or narrow thread or piece of
cotton drawn to a fine point and made to touch the
cornea as the lids are kept wide open, the patient
not being conscious of the contact; anterior cham-
ber shallow ; pupil dilated 4 or 5 millimeters ; pain ;
increased tension ; cupping of the disc ; arterial pul-
sation ; halos and dimness of vision and diminution
of the field of vision; range of accommodation di-
minished.
Glaucoma seldom develops before the age of
twenty-five. Both eyes may be affected, but usu-
ally one is often affected long before its fellow.
Myopic eyes seldom develop glaucoma ; therefore it
is much more common in eyes that are hyper-
metropic.
GLAUCOMA. 283
Varieties of Glaucoma. These are many. Pri-
mary and secondary; primary glaucoma develops
without any previous disease of the eye, whereas
secondary glaucoma develops as a consequence of
a previous disease (iritis, cyclitis, uveitis, injuries,
etc.). Primary glaucoma is recognized in three
forms: acute, inflammatory and chronic non-
inflammatory; this latter is also called simple
chronic glaucoma. The chronic inflammatory va-
riety is also called subacute or chronic congestive
glaucoma.
Differential Diagnosis Acute Inflammatory
Glaucoma, (i) Sudden onset; (2) intense pain;
(3) marked inflammation of eyeball; (4) in-
creased tension. May terminate ( i ) in total blind-
ness in a few hours (glaucoma fulminans or malig-
nant glaucoma). (2) After several attacks the
eyeball may remain stony hard and blindness re-
sult (stone blind) (glaucoma absolutum) ; or (3)
if inflammation persists the condition is one of
chronic inflammatory glaucoma.
Chronic Non-Inflammatory (Simple Chronic
Glaucoma) . This is the very opposite of the acute
inflammatory variety, as it is very insidious or slow
in its development, and patients occasionally verge
onto blindness before coming under observation.
This variety might be overlooked or mistaken for
optic atrophy, if it were not for the cupping of the
disc.
Prognosis. The earlier the case comes under
284 THE OPHTHALMOSCOPE.
observation and treatment, the better, and the more
favorable the prognosis, and, vice versa, the longer
the treatment is delayed the more unfavorable the
case becomes and blindness may result as also loss
of the eye. Acute and uncomplicated glaucoma
receiving prompt treatment gives a favorable prog-
nosis. Cases of chronic glaucoma do not offer a
very encouraging prognosis ; considerable degener-
ation has very likely taken place and the field of
vision has very likely been cut down and visual
acuity diminished.
Treatment. This resolves itself into the sur-
gical, local medication, and internal treatment.
The surgical treatment is that of iridectomy. The
local medication is by myotics, drugs which con-
tract the pupil and therefore, if possible, draw the
iris away from the angle of the anterior chamber,
whereas if left alone and a myotic is not used the
iris is likely to adhere and block the canals of
Fontana and Schlemm. Of the myotics, eserin
in the strength of J/ to 2 grains of the sulphate
to an ounce of water may be prescribed, and one
drop of this solution, dropped into the eye every
three or four hours until the tension is reduced,
and then to be instilled three times a day. Pilo-
carpin nitrate in similar strength or stronger
may be used in place of -the eserin. Knowing
the decided danger or tendency for glaucoma to
affect the fellow eye, it is good practice to use the
myotic in both eyes, but not quite so freely in the
GLAUCOMA. 285
unaffected eye. It is also good practice to combine
an equal amount of cocain with the myotic, as the
myotic is thereby more readily absorbed. If the
pain is unusually severe and does not yield after a
few instillations of the myotic, it may be necessary
to apply hot fomentations (cloths wrung out of hot
water), to draw blood from the temple with the
natural or artificial leach, and also to give a hypo-
dermic of morphia. Internally the salicylate of
soda should be given in large doses frequently re-
peated. The bowels should be kept open. Gentle
massage of the eye through closed lids is good prac-
tice, as it often does good, but must not be severe or
persisted in if the pain is increased thereby.
Whether the local or internal treatment gives relief
or not it is wise to perform an iridectomy as soon
as possible.
Secondary Glaucoma. This variety of glau-
coma, as its name implies, is brought about by a
previous injury or disease, namely, iritis, cyclitis,
swollen or dislocated lens, etc.
Treatment. This is practically the same as for
primary glaucoma. The swollen or dislocated lens
should be removed if it is the cause of the glau-
coma. When the glaucoma is brought about by ad-
hesion of the iris to the lens capsule (iris bombe)
an iridectomy or iridotomy must be performed.
Eyes with absolute glaucoma require enucleation
for relief of the pain.
INDEX.
Absolute scotoma, 147
Accommodation, 18, 22
Acuity of vision, 140, 141
Aerial image, 30, 32
Albinism, 106
Albino, 9, 106
Albuminuric retinitis, 193, 194,
195 (Plate IV.)
atypical forms, 196
of pregnancy, 196 (Plate V.)
Amaurotic cat's eye, 224
family idiocy, 227, 228
Amblyopia, toxic, 245, 246
Aneridia, 100
Anemia of retina, 162, 163
causes of, 167
treatment of, 167
Aneurism of retinal vessels, 153,
154
Angioid streaks, 228
Anomalies, congenital, 98, 99,
loo, 101, 102, 103, 104, 105, 106,
107
Anterior polar cataract, 102, 103
Apoplexy of the retina, 186, 187
(Plate III.)
cause of, 187
prognosis, 187
treatment, 187
Aqueous humor, 79, 131
oblique illumination, 37, 38,
39, 40, 41, 42
ophthalmoscopic examination
of, 13, 14, 26
287
Arcus senilis, 128
Argand burner, n
Argyll-Robertson pupil, 252
Arterial pulsation, 184, 282
Arterio-sclerosis, 151, 152
Artery, central, 113, 122
decrease in size of, 151
embolism of (Plate II.)
increase in size of, 150
persistent hyaloid, 105, 106
Ascending neuritis, 238, 239
Astigmatism, 74
compound hypermetropic, 75
compound myopic, 75
mixed, 76
simple hypermetropic, 75
simple myopic, 75
Atrophic cup, 233
Atrophy of the choroid, 261
of the disc, 162, 163, 238
of the optic nerve, 246, 247
(Plate IX.), 248 (Plate
X.), 252, 257, 258
cause of, 257
diagnosis of, 258
prognosis, 258
treatment, 258
primary, 255
retina of the, 271
secondary, 255
Atypical forms of albuminuric
retinitis, 196
Beam of light, 48
288
INDEX.
Black appearance of the pupil, 9
Blindness, 160, 161
Blind spot, HI, 146
Blood-vessels, 121, 127
new formed, 152, 153
Bracket, 10, 11
Brain tumor, 195
Bright's disease, 193, 194
retinitis due to, 193, 194
Briicke's muscle, 90
Cataract, anterior polar, 102, 103
black, 134
choroidal, 102, 134
cortical, 102, 134
lamellar, 102, 103
Morgagnian, 134
nuclear, 133
posterior polar, 102, 103
pyramidal, 102
ripe, 102
secondary, 271
senile, 102, 134
traumatic, 134
Catoptrics, 49, 50
Central artery, embolism of, 164
(Plate II.)
thrombosis of, 164
Cherry red spot (Plate II.)
Chimney, cover, 10, u, 42
Choked disc, 235, 236, 237, 238,
239
Cholesterin crystals, 139
Choroid, 84, 126
anatomy of, 84, 85, 86
atrophy of, 261
changes in color, 259, 260
colloid disease of, 271, 272
coloboma of, 105
degeneration of, in myopia,
271
Choroid, diseases of (Chapter
X.)
hemorrhage in, 261
hyperemia of, 260
inflammatory products in,
200
pigmentation of, 126, 260
rupture of, 273, 274
suppurative, 272
sarcoma of, 274
tigree, 127
tubercle of, 275
Choroidal atrophy, 261
ring, 116, 117
vessels, 127
Choroiditis, 261 (Plate XL)
central, 262, 270
changes in lens and iris in,
271
in retina and disc, 271
in vitreous, 271
diffuse, 269, 270
disseminated, 262, 267
cause of, 268
prognosis of, 268, 269
treatment of, 269
exudative, 263
guttate, 262, 270
macular, 270
metastatic, 262
myopic, 262, 271
old, 262
plastic, 262
posterior, 262
purulent, 262, 272, 273
recent, 262
senile, 262, 270
syphilitic, 262
varieties of, 262
with descemetitis, 272
Choroido-retinitis (Plate XI.)
Cicatricial bands in retina, 153
INDEX.
289
Ciliary body, 89, 90
Cilioretinal vessels, 124
Circinate retinitis, 226, 227
Cloquet's canal, 106
Cocain, 16, 17
Colloid disease of the choroid,
271, 272
Coloboma of the choroid, 105
of disc, 105
of iris, 100
of lens, 105
Color of disc, 112, 121, 229, 230
Color of fundus, 108, 109, 125
affected by light em-
ployed, 109
in dark eyes, 109
in fair eyes, 109
in mulatto, 109
of various areas, 109, no
Compound astigmatism, 75
lens, 70
Concave mirror, 52, 53, 54
Condensing lens, 30. 31, 32, 33
Congenital anomalies, 99, 100,
101, 102, 103, 104, 105, 106, 107
Conjugate foci, 53, 63, 64
Connective tissue on disc, 107
Corectopia, 101
Cornea, 81, 82, 83
anatomy of, 81, 82, 83, 84
oblique examination of, 37,
38, 39, 40, 41. 42
ophthalmoscopic examination
of, 13, 14, 26
smoky appearance of, 128
reflex, 126
Cover chimney, 10, n, 42
Crescent, 116
myopic, 116, 118. 271
Cribrosa. lamina, 115
Cup, atrophic, 233
glaucoma. 233
24
Cup, physiologic, 113, 114, 233
to estimate depth of, 114,
US, 267
Cupping, diagnosis of normal and
abnormal, 114, 115, 234, 235
Cycloplegic, 15, 16, 17, 18
Cylinders, 68, 69, 70
Cysticercus, 139
D
Dark-room, 9, TO
Davis, Dr. E. P., 198
Descemetitis, 128
de Schweinitz, Dr. G. E., 216
Detachment of the retina, 219,
220, 221
De Zeng patent, 6, 7, 8
Diabetic retinitis, 206 (Plate VI.)
course, 206
prognosis, 206
treatment, 211
Diopters, 67, 68
Direct method, at a short dis-
tance, 13, 14, 26
close to patient. 23
enlargement of image, 27
estimation of refraction, 72,
73, 74, 75, 76
examination by, 13, 14, 26
schematic eye. 15
Disc, 33, 1 10. HI (Chapter IX.)
Diseases of the choroid (Chap-
ter X.)
of the optic nerve (Chapter
IX.)
of the retina (Chapter VIII.)
of the retinal vessels (Chap-
ter VII.)
of the vitreous (Chapter
V.)
Dislocation of the lens, 102, Fig.
63. 135
290
INDEX.
Disseminated choroiditis, 262
Distortion of objects, 177
Dots, 185
Crick's, 185
Gunn's, 185
Mooren's, 185
Nettleship's, 185
neuritic, 197
Tay's, 270
E
Edema of the retina, 180
Electric flash, 160, 161
retinal changes from, 160.
161
Electric light, u, 12, 160, 161
Embolism of central artery, 164
(Plate II.), 167,
168, 169
causes of, 169
diagnosis of, 169
prognosis, 170
treatment of, 170
Emmetropia, 71, 72, 73
Entozoa, 131
Euthalmin, 17
Eserin, 17
Examination, methods of, 13, 14,
23, 26, 29, 30, 31, 32, 33, 34
by focal illumination, 37, 38,
39, 40, 41, 42
direct at short distance, 13.
14, 26
close to patient, 23
indirect, 29, 30, 31, 32, 33, 34
Excavated disc, estimating ex-
tent of, 114, 115
Exudative choroiditis, 262
atrophic stage, 261
exudative stage, 262
Eye (Fig. 61)
anatomy of (Chapter III.)
Eye, astigmatic, 74
emmetropic, 71, 72, 73
hypermetropic, 65, 70, 71
myopic, 64, 71, 72
schematic, 14, 15, 20
F
Field, 142
of vision, 143
field chart, 144
Fixed opacity, 128, 129
determining position of
130, 131
Floating opacity, 136
Focal illumination, 32, 37, 38, 39*,
40, 41
Focus, 48, 64
conjugate, 53, 63, 64
negative, 65
ordinary, 64, 65
real, 48, 49
virtual, 49
Foreign bodies in cornea, 128,
129
aqueous humor, 131
lens, 132, 133
vitreous, 136, 137
Fovea centralis, 97, 125
Fundus, 108
normal, 108, 109
color of, 108, 109, 125
in the albino, 109
in the blonde, 109
in the mulatto, 109
reflex, 26, 109, iio> ill
G
Gas, 10, ii
Glaucoma, 15. 16, Chapter X.
(Plate XIT.). 275. 276, 277
cause of, 276
cup, 232 (Plate XII.), 233.
234
INDEX.
291
Glaucoma, treatment of, 284, 285
varieties of, 283
Glasses, correcting, 19
Glioma, of the retina, 224, 225,
226
pseudo, 226, 262
Gould, Dr. G. E., 141
Gunn's dots, 185
Guttate choroiditis, 270
H
Hansell, Dr. H. R, 233
Helmholtz's ophthalmoscope, I
Hemeralopia, 211
Hemorrhage, 154
causes of, 157
choroidal, 261
retinal, 154, 155, 156, 157, 186
subhyaloid, 157
vitreous, 157
Hemorrhagic retinitis, 187, 196
Hermance, Dr. W. O., 248
Homatropin, 18
Hulings-Jackson, 17
Hyaloid artery, 105, 106
Hyperemia of the choroid, 259,
260
of the optic disc, 237
of the retina, 158, 159
Hypermetropia, 27
tests for, 27
Hyphema, 131
Hypopion, 131
Indirect vision, 142, 143
Illumination, 10
candle, 10
daylight, 10
electric, ir, 12
focal, 37. 38, 39, 40, 41
gas, 10
Illumination, oblique, 37, 38, 39,
40, 41, 42
oil, 10
Welsbach, u
Image, aerial, 30, 32
formed by concave mir-
ror, 54, 55, 56
convex mirror, 56,
57
of eye ground, 27, 28,
36, 37
formation of, 32, 66
inverted, 30, 32
size of, 27, 28
upright, 23, 26, 66
virtual, 23, 26, 66
Indirect method, 29, 30, 31, 32,
33, 34
examination by, 29, 30,
31, 32, 33, 34
refraction by, 35, 36
value of, 34, 35, 36
Intense light, effect of (Sec
Electric and Snow Blindness),
160, 161
Intensity of light, 44, 45
Interstitial keratitis, 131
Intra-ocular optic neuritis, 239,
240
Irideremia, 100
Irido-choroiditis, 272
Irido-donesis, 135
Iris, 86, 99, 100
anomalies, 100, 101, 102
anatomy of, 86, 87, 88, 89
changes in, 132
congenital coloboma, 100
examination of, 131, 132
Iris diaphragm chimney, 10, II
reaction, 132
292
INDEX.
Jennings, Dr. J. E., 102, 138
K
Keratitis, interstitial, 131
punctata, 131
Lamellar cataract, 102, 103
Lamina cribrosa, 96
vitrea, 85
Lamp, electric, 6, 7
oil, 10
Lens, 59
convex, 59, 60, 62, 63
concave, 60, 61, 62, 63
coloboma of, 105
combinations, 4, 5
condensing, 30, 31, 32, 33
crystalline, 92, 93, 94
cylinder, 68, 69, 70
dislocation of, 102, 135
foreign bodies in, 132, 133
numeration of, 67, 68
oblique illumination with,
38, 39
ophthalmoscopic examination
of, 132
smoky appearance of, 132
varieties of, 59, 60, 61, 62
Lenticonus, 104
Lenticular opacities, 102
color of, 102
position of, 102
Leucoma, 129
Leukemic retinitis, 188, 189
Leucosarcoma, 274
Light, 10, ii, 12, 44
streak, 122
Locomotor ataxia, 257
Loring, 2, 3, 4
Loring's ophthalmoscope, 2, 3, 4
Loupe, 40, 41
Luminous ophthalmoscope, 6, 7
M
Macula, 22, 97, 129
appearance of, 97, 125, 126
circulation at, 97, 98
coloboma of, 105
lutea, 97, 125
reflexes, 125
region, 97, 126
symmetric changes in in-
fancy, 227
vessels, 97, 98
Magnification by direct method,
27
by indirect method, 37
Magnifying glass, 31
Mariotte's blind spot, 46
Margin of the disc, no
Media, 27
of the eye, 27
examination of, 27
Medullary sheaths, 106, 107
(Plate IX.)
Medusa, 240
Melanosarcoma, 274
Membrana cribrosa, 115
Membrane, pupillary, 101, 102
Metamorphopsia, 177
Metastatic choroiditis, 262
Micropsia, 177
Microphthalmos, 99
Miliary tuberculosis, 275
Mirror, 2
concave, 2, 12, 13
reflection from, 52, 53, 54
convex, 56
movement of, 13, 14
perforation in, 2
plane, 6, 12
reflection from, 2, 8, 12
INDEX.
293
Mirror, retinoscopic, 76
sight-hole in, 2, 6
stationary, 8
tilting, 2, 7, 8
Mixed astigmatism, 76
Morton's ophthalmoscope, 2, 5
Muller's fibers, go
Musser, Dr. J. H., 248
Mydriatics, 15, 16, 17, 18
objections to, 15, 16, 17, 18
uses of, 15, 16
Myopia, 29
description of, 64, 71, 72
test for, 71, 72
Myopic choroiditis, 271
crescent, 271
degeneration of the choroid,
271
N
Nebula, 129
Negative focus, 65
Nerve, optic, 95, 96
-fibers, 95, 96
-head, 96, 97, 100, m
diseases of (Chapter IX.)
Nettleship's dots, 185
Neuro-retinitis, 243, 244, 245
Neuritis, optic, 239
interstitial, 244, 245
retrobulbar, 239, 244, 245
New vessels in vitreous, 153
Nicotin, chronic poisoning, 245
Night-blindness, 211
Normal eye, 71, 72, 73
cupping, 113, 114
fundus. See Chapter IV.
Nubecula, 129
Nystagmus, 106
Object lens, 30, 31, 32, 33
handle for, 31
Oblique illumination, 37, 38, 39,
40, 41, 42
examination by, 37, 38, 39,
40, 41, 42
Observer, 18, 19, 20, 21
Opacities, cholesterin crystals,
139
corneal, 128, 129, 130, 138
fixed, 139
floating, 139
hemorrhages, 157
in aqueous, 138
lenticular, 138
locating the position of, 138,
139
vitreous, 137, 139
Opaque nerve-fibers, 106, 107
(Plate IX.)
Ophthalmoscope, I
choice of an, I
Helmholtz, I
how to use the, 9, 10, 23,
24, 25
Loring, 2, 3, 6
Morton, 2
selection of, I
Thorner, 8, 9
Ophthalmoscopic examination,
23 (Chapter I.)
direct method, 23, 26, 27, 28
indirect method, 26, 29, 30,
3i
Optic atrophy, primary, 246, 247
(Plates IX. and X.)
secondary, 255
simple, 255
Optic disc (disk), in, 112
atrophic cup, 233
atrophy of (Plate X.)
coloboma of, 105
color of, 112, 121, 229, 230
congenital crescent of, 116
294
INDEX.
Optic disc, connective tissue on,
107, 112
cupping of, 231, 232, 233,
234, 235
detailed study of, 112
elevation of, 235, 236, 237
enlargement of, 237
excavation of in atrophy, 233
hyperemia of, 230
in glaucoma, 233, 234, 235
level of, 231, 232
margin of, 112
myopic crescent of, 116, 118,
271
nerve fibers, 106, 107 (Plate
IX.)
physiologic cup, 113, 114
pigment on, 112
pillar of, 230, 231 '
shape of, 112, 113
situation of, 112
size of, in
swelling, estimating extent
of, 237
Optic nerve, atrophy of (Plate
X.)
diseases of (Chapter IX.)
head of, in
Optic neuritis, 17, 18, 235
retrobulbar, 244, 245
Panophthalmitis, 272, 273
cause of, 272, 273
prognosis of, 273
treatment of, 273
Papilla, in, 112
Papillitis, 235, 236, 237, 238, 239
cause of, 241, 242, 243
prognosis, 2Ai
treatment, 243
Papillomacular fibers, 245
Papillo-retinitis, 193, 194, 238
Parallactic movement (Chapter
IV.)
Parallax (Chapter IV.), 115
Pencil, 48
Perforation, central in mirror, 2
Perimetry, 140, 142, 143, 144, 145,
146
Perivasculits, 152
Pernicious anemia, 167
Persistent hyaloid artery, 105.
106
Phthisis bulbi, 273
Physiologic cup, 113, 114 (Chap-
ter IV.) 232, 233
estimation of depth of, 114,
115
to distinguish from patho-
logic cup, 233
Pigment on disc, 120, 121
ring, 1 20, 121
streaks in retina, 228
Pigmentary degeneration of
retina, 211
unusual form (Plate VII.)
Pigmentation of the choroid, 126,
260
Pigmentosa, retinitis, 211, 212
(Plate VII.)
Plane mirror, 12
reflection from, 51, 52
Porus opticus, 113
Position of light, 21, 22
of observer, 20, 21, 22
of patient, 22, 23
Posterior polar cataract, 102, 103
staphyloma, 267
synechia, 131
Postpapillitic atrophy (Plate
IX.)
Primary atrophy of the optic
nerve (Plate X.)
INDEX.
295
Prisms, 58, 59
Proliferating retinitis, 153
Pseudo-glioma, 226
Pulsation, arterial, 154
venous, 123, 124, 154 (Chap-
ter IV.)
Punctate condition of the fun-
dus, 184, 185
Pupil, black appearance of, 9
congenital anomaly, 100, 101.
102
in atrophy of optic nerve,
252
reflex from, 9
Papillary membrane, 101, 102
Purulent choroiditis, 262
R
Randall, Dr. B. A., 140
Ray, 45
Rays of light, 12
convergent, 12, 47, 48
divergent, 12, 47
emergent, 45, 46
incident, 45
parallel, 12, 47
reflected, 12
Reflection, 12, 49, 50
laws of, 50
Reflex, corneal, 126
chcfroidal, 26
fundus, 26, 109
red, 26, 109
Weiss, 125
Refraction, 57, 58, 59, 60, 61, 62
Retina, 90, 124
anatomy of, 90, 91, 92
anemia of, 161
atrophy of, 271
changes in vascularity of,
157, 158
commotio, 224
Retina, detachment of (Plate
VIII.), 219, 220, 221
causes of, 221
diagnosis, 219, 220, 221,
222
prognosis, 223
treatment, 223, 224
diseases of (Chapter VIII.)
edema of, 180
exudation into, 181
glioma of, 224, 225, 226
diagnosis of, 226
prognosis of, 226
treatment, 226
hemorrhages into, 154, 155,
156, 157, 158, 186
hyperemia of, 158, 159, 160
inflammation of, 176, 177
irritation of, 160, 161
opacities of, 178, 179, 180,
181
pigment streaks in, 228
pigmentary degeneration of,
214
pigmentation of, 158
rupture of, 224
sclerosis of, 214
shot or watered silk appear-
ance of, 125
transparency of, 125
vessels of, 125
Retinal atrophy, 271
capillaries of, 123, 124
changes due to intense light,
160, 161
circulation of, 125
reflex, 109, 125
veins, thrombosis of, 170, 171
vessels, 123, 124, 125, 148,
149, 150, 151, 152, 153,
154
diameter of, 149, 150
296
INDEX.
Retinal vessels, diseases of, 149,
150, 151
distribution of, 121, 122,
123, 124
light streak of, 122
pulsation of, 123, 124
relative size of arteries,
and veins, 148
sclerosis of, 149, 150, 151
tortuosity of (See
Thrombosis)
walls of, 151
Retinitis, 176, 177
albuminuric, 193, 194, 195
causes of, 178
centralis et striata, 228
circinata, 226, 227
circumscribed, 184
diagnosis of, 177
prognosis of, 177, 178
treatment, 178
(Plate IV.)
varieties of, 196
degenerative, 196
diabetica, 206
diffuse, 182, 183
electric, 160, 161
hemorrhagic, 187, 196
causes, 187
prognosis, 187
treatment, 188
leukemic, 188, 189
neuro-, 196
of pregnancy (Plate V.), 196
pigmentosa, 2ii (Plate VII.)
diagnosis of, 214
treatment of, 214
proliferans, 153
punctata, 184, 185
purulent, 228
secondary, 187, 196
serous, 182, 183
Retinitis, simple, 182, 183
solar, 160, 161
splenic, 188, 189
treatment, 193
syphilitic, 188
treatment, 188
varieties of (Chapter VII.)
Retinochoroiditis (Plate XI.)
Retinoscopy, 76, 77, 78
in astigmatism, 77
in hypermetropia, 77
in myopia, 77
methods of examination, 76
77
mirror, 76
principle of, 76
Retrobulbar neuritis, 244
acute, 244, 245
cause, 245
prognosis, 245
treatment, 245
chronic, 244, 245
cause, 245, 246
prognosis, 246
treatment, 246
Ring, choroidal, 116, 117
pigment, 116, 117
scleral, 116
Room, 9, 10
Rupture of the choroid, 273, 27^
Sarcoma, of the choroid, 274
stages of, 275
Schematic eye, Thorington's, 14
15
Scleral ring, 116
Sclerophthalmia, 99
Sclerosis of the vessel walls
151, 152
Sclera, 79, 80, 81
Sclerotic, 79
INDEX.
297
Scleral ring, 115, 116
Scotoma, 146, 147
Secondary atrophy of the optic
nerve, 255
Selection of an ophthalmoscope,
i
Senile cataract, 102, 134
changes in the blood-vessels,
iSi, J 52
choroiditis, 270
guttate choroiditis, 270
Serous retinitis, 182, 183
Shadow-test, 76, 77, 78
Sight-hole, 2
Simple hypermetropic astigma-
tism, 75
myopic astigmatism, 75
Snow blindness, 160, 161
Sparkling synchysis, 139
Spheres, 59, 60, 61, 62, 63
Spherocylinders, 70
Spiller, Dr. Wm. G., 248
Squint, 22
Staphyloma posticum, 267
Subhyaloid hemorrhage, 157
Subretinal cysticercus, 139
Sweet, Dr. W. M., 233
Symmetric coloboma of the
lenses, 105
dislocation of the lenses, 105
Synechia, anterior, 131
posterior, 131
Synchysis scintillans, 139
Syphilitic choroido-retinitis
(Plate XI.)
retinitis, 188
Tay, 227
Test cards, 140, 141, 142
Thrombosis of the central artery,
164
Thrombosis, of retinal vein, 170,
171 (Plate III.)
causes of, 175
diagnosis, 174, 175
treatment, 175
Tiger-skin fundus, 127
Tilting mirror, 2
Tobacco amblyopia, 245, 246
Tortuosity of retinal vessels, 170,
171
Toxic amblyopia, 245, 246
Tubercle of the choroid, 275
Tumor, brain, 242
Tumors, intraocular, 274
u
Uvea, oo
Uveal tract, 90
V
Vein, central, 122
decrease in size of, 150
increase in size of, 149, 150
Veins, thrombosis, 170
vorticose, 86
Venous pulsation, 123, 124
Vessel walls, sclerosis of, 151,
152
choroidal, 127
cilioretinal, 124
diseases of, 151, 152
new-formed in retina, 152
in vitreous, 153
on disc, 122
retinal, 121, 122, 123, 124
size of, 28, 122
Vision, 140, 141, 142
central, 141, 142
peripheral, 142, 143, 144, 145,
146
Visual acuity (Chapter VI.)
Vitreous, 94, 95, 136, 137
298
INDEX.
Vitreous, anatomy of, 94, 95
changes in choroiditis, 271
cholesterin crystals in, 139
diffuse opacity in, 272
foreign substances in, 139
hemorrhage into, 136
movable opacity in, 137, 138
new vessels in, 153
oblique illumination of, 137
opacities, 136
ophthalmoscopic examina-
tion of, 136, 137
purulent exudations in, 272
Vorticose veins, 86
w
Walls of retinal vessels, 151
white lines along, 152
Weeks, Dr. John E., 241
Weiss reflex, 125
Welsbach, u
Wickerkiewicz, 101
Yellow, reflex of purulent cho-
roiditis, 272
spot, 125
position of, 126
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