THE LIBRARY
OF
THE UNIVERSITY
OF CALIFORNIA
LOS ANGELES
GIFT OF
SAN FRANCISCO
COUNTY MEDICAL SOCIETY
HETEROPHORIAS AND
INSUFFICIENCIES
A CLINICAL STUDY
BY
H. H. SEABROOK, M.D.,
SURGEON, NEW YORK EYE AND EAR INFIRMARY, ETC.
Cbc Ikmchcrbocfccr press
1900
Library
WtO
HETEROPHORIAS AND
INSUFFICIENCIES
A CLINICAL STUDY.
CHAPTER I.
GENERAL CONSIDERATIONS AND METHODS OF
TESTING.
TH E class of cases to be considered here has been
recognized as having had an existence since
\^ the dawn of modern ophthalmology. Von Graefe at-
tempted to solve the problems they presented, and
: although he furnished some valuable ideas for his
: successors to work upon, his knowledge upon the
tf subject would be a poor equipment for an ophthal-
.* mologist of to-day. Donders saw the fallacies of the
work being done in this field, solved in general
Jfc terms the problem of accommodative asthenopia,
624398
2 Hctcrophorias and Insufficiencies.
and found that " as soon as insufficiency of the in-
ternal or external recti muscles in binocular vision
threatens to give rise to muscular asthenopia, it is of
importance that the mutual distance of the glasses
should not aggravate this but rather counteract
it." If spherical glasses are insufficient, we are to
combine with prisms or operate according to
Von Graefe. There is agreement with Helmholtz's
statement that displacement of glasses in a vertical
direction causes more asthenopia than the same
amount of lateral displacement. Except for the op-
erative method indicated, the statements here made
are entirely sound, but cannot be said to suffer from
over-elaboration ; they seem, however, sufficient to
more than cover what is usually done for muscular
asthenopia to-day in practice upon the European
continent. In England signs of interest began to be
manifested regarding these cases over fifteen years
ago, and thanks to the work of Maddox and others
many principles of value were evolved. Previous to
this, Stevens in America had succeeded in attracting
attention by means of his work, his highly enthusi-
astic followers, and his bitter opponents. A portion
of his nomenclature came into general use, and is
here followed. Orthophoria, muscular balance ; het-
erophoria, tendency to deviation ; esophoria, conver-
gence tendency ; exophoria, divergence tendency ;
hyperphoria, upward tendency. These terms were
A Clinical Study. 3
taken to be equivalent to and supersede the old ones
of insufficiency of the interni and externi, even
Duane, whose masterly classification of these condi-
tions has earned deserved recognition, taking this
view ; yet heterophoria means merely a tendency of
the fixation lines away from the object of fixation,
while insufficiency means lack of power. The old
terms for exophoria and esophoria were dynamical
divergence and convergence. It is the intention of
the writer to show that certain forms of heterophoria
may be due to errors of refraction or other optical
defects, others to habit, others to the nervous sys-
tem, and others still to muscular spasm, excess, or
insufficiency. Much has been written upon this
subject in addition to that so briefly mentioned,
some of it of value, and the writer proposes to treat
all of the authors in the most impartial manner, as
he appropriates their ideas whenever he can make
use of them, without regard to their source. He has
no instruments to exploit, no special method of treat-
ment to push, no new general disease which he has
cured through the eye muscles. If, in spite of this,
an original idea or so should creep in among the
others, anybody is welcome to use it as his own.
In discussing the question of correcting the refrac-
tion except as incidental to the treatment of muscu-
lar anomalies, there is of course no intention to
belittle this very important consideration in the
4 Heterophorias and Insufficiencies.
treatment of eye strain. Important as this branch
of the subject undoubtedly is, correction of the re-
fraction may be carried to the point of absurdity.
When a patient with undoubted exophoria and in-
sufficiency of the interni complains of severe head-
ache, dizziness and nausea, excited or increased
when convergence is attempted, it is perfectly silly
to correct .12 or .25 D. of hypermetropia in such
eyes, and yet many have done such things.
In studying the effect of correction of the refrac-
tion upon the ocular muscles, it is absolutely neces-
sary to separate this secondary effect of glasses from
the prismatic effect of a decentred lens. In order
that the optical centre of a lens may be found, the
lens should be held in front of a horizontal line in
such a position that the line is continuous through
the glass without deviation at either edge. The
position of this line is then marked upon the glass
and the process repeated at right angles to the first
position ; the lines cross at the optical centre and
show in a sphero-cylindrical lens the axis of the cyl-
inder and the maximum curve at right angles to it.
In a simple cylinder the axis only can be found, as
there is no prismatic displacement of a line at right
angles to the axis ; a cylinder with horizontal axis
cannot be decentred horizontally, and similarly with
the axis in other meridians. Two lines crossing at
right angles may be used to find the optical centre
A Clinical Study. 5
instead of the above-described method, or the lens
may be held in front of an object, as a candle flame,
in such a position that the reflected images from the
surfaces of the glass are superimposed, when the po-
sition of the images shows the optical centre. The
last method may be used for rapid verification
under certain circumstances, but I prefer the first for
several reasons. The base and apex of a prism are
marked by a line continuous through the glass, just
as the axis of a cylinder is. When the cylinder is
revolved upon its centre, we notice a peculiarity of
prismatic action due to the varying curves, which re-
sults in torsion of lines oblique to the axis, being
most marked at an inclination of 45. While there
are causes for the distortion of objects caused by
glasses other than simple prismatic effect, yet this
prismatic action of the transparent cylinder has not
only an important bearing upon the asthenopia pro-
duced by cylindrical lenses, but, taken in connection
with other prismatic effects of curved surfaces and
applied to the human eye with its frequently de-
centred astigmatic refractive media, it throws an
entirely new light upon many observations in physio-
logical optics and opens up a new field in the ex-
planation of muscular anomalies. A very plausible
connection could be shown between apparent diver-
gence and convergence, the decentred biconvex
lens system between the anterior corneal surface and
6 Heterophorias and Insufficiencies.
the posterior surface of the crystalline lens, and con-
vergent and divergent squint ; its bearing upon the
subject in hand will be shown later.
The primary position of a pair of glasses in front
of the eyes when it is desired to study their effects
upon the ocular muscles is with the optical centres
in the lines of fixation. This position can be ob-
tained with considerable accuracy by sighting ; that
is, by making each examined eye fix the examiner's,
when the optical centre of the glass is placed in the
line which seems to correspond to the line of fixation
of the former and the line of vision of the latter. If
there is a question as to the correctness of this, discs
with vertical stenopaeic slits may be placed in an
adjustable frame, and the distance between their
centres measured when both eyes can see through
the slits at the same time. This distance between
the optical centres (o. c.) should not be confounded
with the distance between the geometrical centres
of glasses to be worn (p. d.), which should come op-
posite the pupils for the sake of appearance and
because there will be less annoyance to the patient
from the refraction and reflection at the edges of the
lenses when they are symmetrical with the pupil.
The prismatic effect of a decentred spherical lens
is obtained by multiplying the distance between the
optical and geometrical centres, taken in centimetres
and tenths, by the dioptric strength of the lens.
A Clinical Study. ^
Thus, a 2 D. lens decentred 3 mm. equals a .6 D.
prism, 2. X -3 = .6. In a pair of glasses the difference
between the primary and secondary position is taken.
Thus, if the glasses are 60 mm. o. c., and the lines of
fixation cut them 57 mm. apart, the prismatic action
of a pair of 2 D. lenses is .6 D., one half in each
eye. If the number of centimetres of decentring
to produce a certain prism is desired, the formula
is v -~ = cms., in tenths. The base of the prism is, of
course, toward the periphery of a concave lens,
toward the centre of a convex one. If the curve of
the lens and the position of the line of fixation are
kept in mind, or put on paper, there can be no con-
fusion. In a cylindrical lens the number of dioptrics
can be found in any direction by means of the lens
measure and prismatic action then figured as for a
sphere.
This easy method of figuring the prismatic action
of a decentred lens is one of the merits of the prism
dioptry system proposed by Mr. Charles Prentice, a
layman, and adopted by many manufacturing opti-
cians throughout the country on account of its sim-
plicity and accuracy when applied to the manufacture
of prisms. I began to use it soon after it was first
suggested. The unit is the prismatic power which
causes I cm. of light deviation at I metre. A lens of
i D. refractive power decentred I cm. = I P. D.
(A D. or D.), i.X i.= i. The best scale I know for
8 Heterophorias and Insufficiencies.
measuring prisms in this system is that of Dr. Ziegler.
I propose to speak of heterophorias in terms of prism
dioptrics, just as we speak of hypermetropia and
myopia in terms of the correcting glass. It is not
necessary in either case to add dioptrics or D. to the
figures in decimals which designate the strength of
the glasses, and it will generally be omitted in the
following pages.
There are a few things regarding the action of
prisms necessary to remember in clinical work.
Prisms beyond a certain strength can not be used in
correcting anomalies of the ocular muscles for several
reasons, some relating to the effect upon the muscu-
lar action, others to mental effect upon the patient,
and yet others to distortion due to prismatic astig-
matism from the varying ratio between the angles of
incidence and refraction. There is a position of
minimum deviation in which a ray of light passes
symmetrically through a prism and other rays suffer
greater deflection. In testing for an object in the
direction of the line of fixation, prisms should be
placed with the surface toward the eye perpendicu-
lar to that line, in order to secure as nearly as possi-
ble the position of minimum deviation. The position
of the prism may assume some importance in the case
of a vertical prism, as, if this is placed in the posi-
tion of minimum deviation for distance, its action is
stronger for near points, the increase amounting to
A Clinical Study. 9
about one-tenth of its strength for the nearest point
at which the eyes are likely to be used.
As will be shown later, patients with inefficient
ocular muscles do not bear prisms as well as those
with strong muscular action ; stronger prisms may
be worn base in for near work than base out for dis-
tance, and with axis horizontal than vertical, and a
3 D. prism over each eye is about the limit of
strength under favorable conditions.
Secondary images due to reflection from the sur-
faces of the glass cause more annoyance in glasses
containing prisms than in those without them, but
the colors due to dispersion, diminution in size and
change of shape of an object, occur to a considerable
extent only when a strong prism is placed before
one eye, as in testing muscular power, or at least are
remarked upon by patients mostly under this con-
dition.
The eye moves toward the apex of a prism in or-
der to overcome the deviation of rays of light
toward the base, and when it is unable to do this
diplopia results, with the image from the eye before
which the prism is placed in the direction of the
apex. The action of the interni in overcoming
prisms base out is called adduction, the externi with
prisms base in, abduction. These terms are easily
confounded, and the mind becomes so confused and
fatigued by them that I propose to use instead the
io Heterophorias and Insufficiencies.
terms convergence and divergence. This can cause
no confusion as the amount is always given in
terms of measurement. P. D's of convergence and
divergence cannot possibly be confounded with
metre-angles or degrees, and those who use the term
degrees, except as applied to perimetric measure-
ments, cannot be cast into any more confusion by
the innovation than that under which they now are
laboring.
There is one point upon which there is agreement
among all investigators in this direction : it is that
abduction or divergence for distance with well bal-
anced and strong eye muscles should be 7. or 8-
[These figures are the same whether the old degree
system, dioptry, or centrad is used. It is beside the
purpose of this treatise to argue regarding these sys-
tems and the new system in degrees of Landolt.
Whatever its demerits, the dioptric system has been
(unofficially) adopted.] The student who finds that
his investigations seem to contradict this standard
for divergence should doubt the accuracy of his ob-
servations ; with an abducting prism the double
images may easily pass unnoticed when they first
appear and then suddenly be observed a consider-
able distance apart at the time a stronger prism than
represents divergence is being used. In such a case
prisms of gradually decreasing strength should be
used until single vision results, then gradually
A Clinical Study. 1 1
increased again. After some experience the exam-
iner will begin with the prism which is to his mind
most likely to represent the divergence to be ex-
pected from the examinations previously made of the
refraction and muscular balance. Until this experi-
ence is acquired it is well to start with a prism of 6.,
7., 8., or 9. It has already been said that divergence
which varies from 7. or 8. may be considered ab-
normal. A certain number of cases show but 6., in
which the only criticism is that divergence and con-
vergence are neither of them at their best. In other
words, amplitude of convergence is slightly below
the standard, and there is no other defect. An oc-
casional case may be found in which the amplitude
of convergence is so great that divergence of 9. or
even 10. is equalized by correspondingly strong con-
vergence and muscular balance is good. Such cases
are liable to develop exophoria later, but for the
time being are sometimes to be complimented upon
their strong ocular muscles. Cases like this are
perhaps not so infrequent as would appear from
our histories. Persons with ocular muscles of that
sort would not be apt to be weak or neurasthenic,
and would hardly be bothered by trivial errors of
refraction.
When it is said that divergence for distant vision
should be 7. or 8., what is really meant is that this is
what should be shown by the candle test at a
1 2 Heterophorias and Insufficiencies.
distance of about twenty feet, which is the usual test.
It is in reality about I. more than the actual power
of divergence for infinity, as I D. of convergence is
necessary for binocular fixation at twenty feet. It
is fortunate that there should be such a definite
standard of divergence for distance, since the power
of divergence for distant vision is an important mat-
ter ; divergence power for any near point theoretic-
ally would equal the amount required to bring the
lines of fixation parallel, added to that which is still
possible with parallel fixation lines when the eyes
are adjusted for infinity. This total is obscured in
making a test at a near point by the accommodative
convergence and certain other factors, but while
neither so definite nor important as divergence ob-
tained for distance, it is a help in comparing the
variations of the muscular action for near and far.
At about thirteen inches (taken as the average read-
ing distance) the prism test shows generally some 6
to 8 D's more of divergence than is shown by the
test at twenty feet, the difference being less than
this in cases of esophoria without insufficiency of
convergence, greater in some cases of exophoria.
Where divergence at thirteen inches is 18. or more,
insufficiency of convergence power at that distance
is almost sure to be present.
Convergence power for near work is of far more
importance than it is for distance, which is also
A Clinical Study. 13
fortunate, as the prism test for convergence at a dis-
tance is very variable. This variability is due mostly
to the much greater difficulty some persons have
of disassociating convergence and accommodation
than others. If the only precaution taken in making
the test is that of dividing the prisms between the
examined eyes (a prism over one eye not only causes
dissimilar images but often convergence in the
armed eye alone, the other fixing), the proportion
between convergence and divergence in eyes with
orthophoria is apt to be as low as three to one. Con-
vergence 1 8., divergence 6. is about the limit for use-
ful ocular muscles on the one hand, while 70. versus
10. or even more can in rare instances be found
among the strong muscles.
Convergence does not represent the strength of the
interni alone, but the nervous energy put into them
as well. In testing this power, being of too impa-
tient a nature to wait for prism exercises or other
slow methods, I have my patients fix a finger, or a
lead pencil, which is gradually approached while the
eyes are armed with converging prisms, and often
with the exclamation, " Oh, that is what you want me
to do," they proceed to converge at distance at least
half as much again as they had succeeded in doing
but a moment before. The rapidity and simplicity
of this will absolutely prevent its acceptance as a
cure, so I shall not elevate it to the dignity of a
14 Heterophorias and Insufficiencies.
method by giving it a name, as the principle itself is
already in use under many high-sounding titles.
A moment's reflection will show anyone that the
prism test at distance does not necessarily represent
the real convergence power as shown by the near
point for convergence. For the latter test I use a lead
pencil or a penholder, as being an object which is
always at hand during an examination, necessitates
accommodation on the part of the patient in order
that it shall be clearly seen, and allows the examiner
to watch the action of the eyes without distracting
his attention. The ease with which convergence for
the near point is accomplished, and the steadiness
with which the eyes hold an object, are of more im-
portance than the exact measure of its distance from
the eyes, and the sensations produced by this mus-
cular action, with the attitude of the patient regard-
ing them, are valuable diagnostic indications. I
would, moreover, as soon trust my observation as to
when convergence is no longer possible as a patient's
statement regarding the production of diplopia.
Tests for the near point usually will show more
power of convergence than the prism test at distance,
because in the latter instance the convergence
without accommodation is an unwonted, as it is usu-
ally an unnecessary, accomplishment. Teaching a
patient how to converge with prisms is simply train-
ing for a test, and has something of the same relation
A Clinical Study. 15
to a cure of weak convergence as training a sensitive
throat for the tongue depressor has to the treatment
of hypertrophied tonsils.
The near point of convergence varies with the
refraction and becomes more and more distant as
age advances and accommodation and the interni
become weaker. Undoubtedly valuable as the test
for the near point of convergence may be, I confine
my use of it mostly to certain purposes already
mentioned, and as a check upon other tests. Thus
if convergence with prisms for a distance seems
below normal, I should reject a diagnosis of insuffi-
ciency of the interni, or of excess of the externi,
if the same eyes showed easy and comfortable
convergence up to two inches or less from the
root of the nose, with or without the correction
of the refraction. The prism test for conver-
gence at the reading distance is unsatisfactory,
although some information may be gained thereby,
as in cases in which hyperphoria occurs only with
convergence.
Sursumduction, or upward movement of an eye, is
tested on the same principle as convergence and
divergence : right sursumduction with the prism base
down right eye, or base up left eye ; left sursumduc-
tion base down left eye, base up right eye. It is hardly
necessary to call attention to the necessity of verify-
ing the base apex line of the prism and having this
1 6 Heterophorias and Insufficiencies.
axis exactly horizontal or vertical in the above
mentioned tests.
Although it has been convenient to consider here
the muscular strength as shown in divergence and
convergence before the muscular balance or tendency
to deviation, the latter should be tested before the
former and preferably after examination of the re-
fraction. The test for balance which is most time-
honored is that by which vertical prisms produce
diplopia, when if the images have a homonymous
or crossed position as regards each other the correct-
ing prism which brings them into equilibrium is con-
sidered the measure of the esophoria or exophoria.
This test should be made at a distant and near point,
first without, then with, the refraction corrected. I
give the conclusions for a near point based upon
tests at 13 inches, as this is the distance I have
chosen for years, although now satisfied that it is
somewhat too near for most cases. The near test
would be best taken at reading distance, which
varies in different individuals.
The test for equilibrium with prisms has been per-
fected, especially by Stevens, and has resulted in the
phorometer with its two prisms of 5 D's base in,
which can be rotated, after the test for vertical
equilibrium has been obtained, for the test of
the lateral tendency, and shows the amount and
nature of the deviation upon its anterior surface
A Clinical Study. 1 7
in prism dioptrics when the images show equi-
librium. It thus gives the novice information
of the deviation with which he has to deal with
some certainty, as he can hardly turn the instru-
ment upside down or otherwise misplace it in
making a test. When the axis of the prism is hori-
zontal, if single vision still obtains it is a fair con-
clusion that divergence is excessive, and another
prism may be added in order to obtain the lateral
images, the prisms in the phorometer only being
rotated in obtaining the measurements. An arm
upon the instrument is very handy for getting the
muscular balance at a near point, although the test
object is more horizontal to the eyes than the position
of the other objects most often seen at this distance
in ordinary work. As a rule, deviations remain latent
with this test to an extent that they do not with the
rod test, although occasionally the reverse is true.
The Maddox glass rod, or series of rods, will pro-
duce a line of light at right angles to the axis when
placed before an eye. This test has the advantage of
indicating the fixing eye (the unarmed one) and al-
lows it to be changed at will by changing the rod from
one eye to the other. When the correcting prism
is obtained its amount and direction are patent, thus
saving the beginner in ophthalmology some mental
effort in ordering correcting prisms. When a devia-
tion has been corrected with a prism in one direction
1 8 Heterophorias and Insufficiencies.
the rod test will show the effect upon the deviation
at right angles to it, a very important consideration
in certain instances, as when with a correcting prism
for hyperphoria we wish to test exophoria or eso-
phoria as compared to the same deviation before
the correction. The rod test also allows of an ex-
amination toward the periphery of the field more
accurate than that of the phorometer, when we
wish to see if the deviations are comitant, but is of
no definite use in testing for reading distance. I
can hardly see how either of these tests can be
dispensed with.
The old screen test, in which one eye is covered,
then uncovered, and its deviation noted while the
other fixes, was in my hands so contradictory and
unreliable long ago, that when Duane modified its
use by adding a subjective element, giving the paral-
lax test, I lacked sufficient confidence in the latter to
use it, in which I may be wrong. Maddox rejected
the double prism with bases meeting at the centre
for the rod test, and various attempts have been
made to revive its use for certain purposes, with but
little success.
Having attempted to indicate the methods of ex-
amination which were followed in obtaining the
clinical data here used, I shall treat the subject of
heterophorias under the following heads: Hyper-
phoria; Esophoria, first, the accommodative, second,
A Clinical Study. 19
esophoria from habit, lastly, esophoria from insuffi-
ciency of the externi or excess of the interni; Exo-
phoria, accommodative and muscular; and lastly
Insufficiency of Convergence, Inefficiency of the Ocular
Muscles, or Neurasthenic Muscular Asthenopia. It
may be observed that this class of cases is not in-
tended to comprise, except as occasional reference
may occur, those which have spontaneous diplopia,
since I regard these as either cases of periodic squint,
paresis of an ocular muscle, or of an associated move-
ment ; neither are other cases of evident strabismus
without diplopia to be considered in detail. Although
in practice it is difficult to draw the dividing line,
it is primarily my desire to further definite knowl-
edge regarding a class of cases in which individual
muscles may of course be affected, yet the deviation
can only be demonstrated by the heterophoria
shown with appropriate tests.
It is lack of definite knowledge concerning devia-
tions of both eyes above or below the horizontal
plane, or inclinations of the physiological vertical
meridian, which prevents consideration of these sub-
jects here; at present, although the germs of ideas
may be working in the brains of investigators upon
these subjects, we can hardly accept information as
definite where the diagnosis depends upon unproven
points in physiology and optics and treatment con-
sists of muscular exercises with oblique prisms, or
2O Heterophorias and Insufficiencies.
tenotomy of the upper half of one lateral muscle and
lower half of its opponent. Torsion will receive
some incidental consideration in dealing with muscu-
lar deviations connected with oblique astigmatism.
Before proceeding to the symptoms of the special
deviations to be considered, it seems well to draw
attention to certain signs of ocular asthenopia com-
mon to the different errors. They are mainly head-
ache, dizziness and sensations of nausea, pain in the
eyes, retinal asthenia or hyperesthesia, congestion
of the palpebral or ocular conjunctiva. Any of
these may be due to muscular anomalies; pain in the
eyeballs seems often to occur from nutritive disturb-
ances, as may conjunctival congestion, although the
latter is generally connected with chronic nasal
catarrh. Relief of conjunctival congestion by
glasses may be due to protection of the eyes from
dust and chemical rays of light, has occurred with
plane glasses, or ridiculously weak spherical lenses,
and is no proof of relief of eye strain. Asthenopic
symptoms sometimes disappear when conjunctivi-
tis is successfully treated. Temporal headache is
usually due to astigmatism, the pain being most
severe on the side of the functionally better eye,
this being in men the right when refraction and
vision are practically equal, because their habit of
"sighting" objects with this eye renders them
more " right eyed " than women. Next to eye
A Clinical Study. 2 1
errors, tobacco and whiskey in men, uterine trouble
in women, are the most important factors in tem-
poral headache. Frontal headache, when dull, may
be due to errors of refraction, but if severe and per-
sistent suggests insufficiency of the interni, or dis-
ease of the frontal sinus. Supra-orbital neuralgia
with tenderness over the nerve is usually unilateral
and is best treated with quinine unless the pain is
severe, radiating and persistent, with much lacrima-
tion, when it should be referred to nasal obstruction,
ethmoidal disease, or disease of some other of the
accessory sinuses. In this latter condition there
may be ciliary pain and lowered intra-ocular tension.
A feeling of pressure over the top of the head
about the fronto-parietal suture is from anaemia, not
eye strain, and localized pain over one parietal pro-
tuberance is not an eye symptom, although its pres-
ence with accompanying tenderness is not a positive
diagnostic sign of tumor of the brain, as is sometimes
stated. Very severe headache with vomiting, com-
ing on suddenly in persons who have not been sub-
ject to headaches, should always be regarded with
suspicion, and if persistent, it will perhaps be neces-
sary for a diagnosis between beginning cerebral dis-
ease and some lesion of the digestive organs to wait
for further developments.
In " bilious attacks " there is sometimes paresis
of an ocular muscle or of an associated movement
2 2 Heterophorias and Insufficiencies.
at the time of an attack which recurs with such
attacks for years, and just such conditions of the
muscles may occur and prove very misleading to the
oculist in cases of central disease of the nervous
system. Take, for instance, a case of recurrent
pachymeningitis in an early stage, with headache
and spasm of convergence from irritation of the con-
vergence centre, or some other muscular trouble
from central lesion which resembles some muscular
excess or insufficiency in which treatment usually
causes relief, and in such a case relief to the head-
ache follows treatment of the eye muscles. It is
hard to avoid mistakes in such cases, yet in them
mistakes are very awkward ; it weakens a man's local
influence as an authority on muscular asthenopia
when some of his medical neighbors have attended
autopsies upon the late subjects of some of his late
cures, and have not exercised that charity regarding
faulty diagnosis which seems so often to begin at
home.
Pain in the back of the neck, with dizziness and
nausea, should immediately excite suspicion of
heterophoria, or insufficiency of the ocular muscles.
Tenderness over the upper portion of the spine, or
the adjacent sensory nerves, does not argue against
this. Similar pain with or without general head-
ache has been known to occur in disease of the
sphenoidal and ethmoidal sinuses, is present in brain
A Clinical Study. 23
disease and lesions of the upper portion of the spine,
and is given as a common symptom in nephritis,
gout, stomach, intestinal and liver diseases, and
especially in neurasthenia. In neurasthenia these
symptoms I am satisfied should usually be referred
to the eyes, and in particular to the ocular muscles.
In cases in which these symptoms are especially
dwelt upon as diagnostic of the general nervous con-
dition they are frequently helped by treatment of
eye strain, and I have myself sometimes in this
manner received credit for curing neurasthenia
through the eyes, although so far as I know I have
never seen a case in which I could positively and
justly claim any such cure. The same holds good
in other conditions; the so-called gouty headache,
and that of nephritis, may not uncommonly be re-
lieved through eye treatment, because it was a
symptom of an eye condition, not of gout, or kidney
trouble ; yet it would be absurd to claim that the
general disease had yielded to cylinders, prisms, or
operations upon the eye muscles. In patients with
digestive disturbances, dizziness and nausea are more
apt to occur from muscular asthenopia than in other
cases, and these sensations no doubt occur frequently
from other causes; yet so many of these cases are
more or less benefited by eye treatment that, as
before mentioned, the symptoms should excite sus-
picion of eye strain. Cases are seen by the eye
24 Heterophorias and Insufficiencies.
specialist in which eye treatment has been unduly
delayed while general treatment was kept up for eye
symptoms; he has no good opportunity to know
the other side of the question.
The general rule of double causation must be ap-
plied in these cases; there are cases of eye devia-
tions of the same character as those which cause
trouble, which with just as hard use of the eyes
cause no asthenopic symptoms whatever; hence
these symptoms must be referred, when they occur
from eye errors, to such errors working upon some
general condition susceptible to these symptoms.
In the cases of choreic blepharospasm, or spasm
of the facial muscles, occurring with or without other
choreic symptoms, we are often able to obtain relief
by treatment of heterophoria, refractive error, or
inflammatory lesion of the eye or appendages, yet
in an active stage of general chorea it has seemed
to me that treatment of the ocular muscles some-
times did more harm than good ; prisms cannot be
kept straight in front of the eyes, the conditions
of the muscles are so variable that it is hard to tell
the nature of the original tendency, and muscle
operations are likely to increase general nervous
irritability.
Dizziness may go on to vertigo in certain cases of
eye strain. Dizziness and giddiness are used prop-
erly as synonymous terms, while by vertigo is meant
A Clinical Study. 25
temporary loss of consciousness. Vertigo in this
sense is not of frequent occurrence from hetero-
phoria, yet in occasional instances may take the
form of fainting spells accompanied by falling.
This is the only kind of epilepsy I have personally
known to be relieved by eye treatment.
When a patient who is in the habit of reading
himself to sleep gets eye strain and cannot sleep be-
cause he cannot read with comfort, correction of his
eyes may cure his insomnia; yet eye treatment as a
cure for insomnia has usually failed in my hands.
I have seen cases of nervous unrest accompanying
hyperphoria or esophoria in which the patient said
she felt like throwing herself out of the window, and
met with one case in which there was ground to be-
lieve that the muscular deviation had actually helped
to cause a temporary suicidal mania.
Statements on record to the effect that severe
general headache, spinal irritation, dizziness and
nausea are common symptoms of refractive error,
because they disappear with correction of the refrac-
tion, are to be received with caution; a careful con-
sideration of this matter convinces me that these
symptoms are in such cases usually due to hetero-
phoria which is incidentally relieved by correction
of the refraction, as in accommodative esophoria.
Although the muscular deviations accompany-
ing errors of refraction will receive our first
26 Heterophorias and Insufficiencies.
consideration, the symptoms will not be described
from this class so much as from those cases in which
the refractive error played no part, even if it existed.
It is well to remember that a headache which
wakes a patient from sleep is not likely to be due to
the eyes, and if it markedly decreases or disappears
after the patient has been up and about for a time
the eyes may be eliminated as a causative factor,
except in a few cases where there is an eye error for
near work which does not cause strain for distant
vision ; these latter cases are free from headache
when they do no near work, but after hard use of
the eyes in the evening may wake with a headache
the next morning, which passes off later in the day.
It seems to be accepted as a matter of course that
the asthenopia due to muscular deviations will cease
if one eye only is used. The closing of one eye
long enough for diagnostic purposes in the usual
class of patients who suffer from asthenopia, with
their weak nerves and strong desire for binocular
fixation, is fraught with difficulty, and this principle
finds its application mostly in the treatment of aniso-
metropia. There may be an occasional case in which
it is advisable to shut off one eye with a piece of
ground glass in a spectacle frame for the diagnosis or
relief of asthenopia, and personally I prefer this
method to the removal of an eye which must neces-
sarily be possessed of useful vision, a feat which I
A Clinical Study. 27
am forced to believe by reliable authority has been
performed for the relief of symptoms supposed to
be due to heterophoria.
Of course the symptoms of muscular asthenopia
depend upon binocular vision, and the man who ex-
pects to cure strain in one eye by tiring them both
would hardly be expected to meet with success ; yet
I frequently find a patient with a plane or nearly
plane glass over one eye and a strong lens over the
other, who announces that the oculist who gave these
glasses found that one eye was doing all the work,
and corrected the other with a glass so that it might
relieve the strain from which the first one was suffer-
ing. Many men have gone through the phase of
full correction of each eye, as their seniors did not
properly warn them, not caring to dwell upon that
time when they too had discovered the secret of the
cure of all asthenopia with good vision in either eye.
A patient with anisometropia with much difference
between the refraction of the eyes will bear full cor-
rection of the two eyes just so long as he does not
use them together. There are many other diffi-
culties of fusion in such a case in addition to the
esophoria in one lateral direction, the exophoria in
the opposite one, the hyperphoria on one side upon
looking down, on the other when looking up, from
the prismatic action of one lens in excess of the
other; even if the patient looks through the centre
28 Heterophorias and Insufficiencies.
of the lens, or the English proposition is carried out
to have the strength of the lenses similar at the
periphery with a central paster to correct the eye
with greater error, the unequal antero-posterior
shifting of the nodal points, with other reasons for
dissimilar retinal images, will still obtain.
To my mind the most satisfactory combination
of eyes for a life's work would be to have one em-
metropic, the other myopic about 3 D's. In cases of
anisometropia in which the difference corresponds
to this, yet astigmatism is present, it is well to
consider the astigmatism alone ; in myopia with a
difference of 2. or 3. between the eyes it is well to
have a pair of glasses in which the eye with less
myopia is fully corrected by a glass and the other
lens matches this or nearly so. I carry this idea
so far as to occasionally correct in hypermetropic
and presbyopic cases the eye with the greater error
for distance, and with a glass which equals this in
strength, as nearly as the case will allow, the pres-
byopia of the other as well. It is absolutely nec-
essary to determine that the first eye does not
strain its accommodation in order to read with the
other, and render such correction impracticable.
The scope of this treatise will not allow a full dis-
cussion of this class of cases, in which any man is
liable to meet with disaster, further than to give a
few additional points regarding correction. The
A Clinical Study. 29
deviation of the eye with poorer vision (fortunately
the one with greater error in most instances) is deter-
mined by certain conditions in the better eye as
well as its own weaknesses. Note in this connec-
tion the effect upon the defective eye of correcting
glasses upon the better eye in squint cases. It is a
matter of great importance to find out in such cases
just how strong is the impulse to binocular fixation
and the ability to ignore or suppress the image of
one eye; if the muscular condition is bad and the
tendency to binocular fixation can be strengthened,
it is justifiable to cultivate the latter in the interests
of vision, although muscular asthenopia may result
which demands treatment.
The difference in strength between two glasses to
which the eyes may accustom themselves depends
upon the age and character of the patient and the con-
dition of the ocular muscles, with some other factors
which cannot be determined clinically at present.
With one exception, cylinders with considerable
amount of difference are borne better than spheres
with like differences because there is no prismatic
effect in the direction of the axis ; differences between
cylinders with the axes vertical are better borne than
in those with the axes horizontal. Patients with
strong muscular action, especially in the direction
of difference (for instance, strong sursumduction
with horizontal cylinders) bear differences better than
30 Heterophorias and Insufficiencies.
those with weak muscular action ; this is partly local,
partly because the latter condition accompanies neu-
rasthenia. Sursumduction of i. is weak, 2. ordinary,
2.50 and above strong. People who turn the head
and look through the centres of their glasses bear
glasses better than those who look at objects through
or beyond the edges. Difference of glasses of 2. may
be well borne by young people (under twenty years
of age), while I. may be the limit past middle life.
The best borne differences are in cylinders with verti-
cal axes as before mentioned, and the worst are a
vertical cylinder over one eye, horizontal over the
other, in this case concave cylinders being worse
borne than the convex; in myopic astigmatism cyl-
inder .5 in each eye, one vertical, the other horizon-
tal, is usually not a complete success.
Let me repeat for the benefit of those who have
had no trouble so far in giving glasses with great
differences, that almost invariably the patient in
such cases suppresses the image of one eye, or at
least does not have binocular vision. The only
cases in which such a correction is really indicated
occur among patients with no tendency to asthenopia
where it is desirable to better the field on the side
of the defective eye.
CHAPTER II.
HYPERPHORIA.
THE symptoms of hyperphoria differ from those
of other forms of heterophoria mostly in de-
gree. The headache is below the occiput, or may
be general and accompanied by dizziness and nausea ;
it is pretty constant, although varying in intensity,
in many cases perhaps passing away during a night's
rest and increasing toward evening, unless the pa-
tient rests with the eyes shut during the day;
occasionally in hyperphoria cases supra-orbital or
ciliary pain on one side is present, but it is doubtful
whether this can be due to the muscular deviation
alone. In this form of heterophoria congestion of
the eyeball accompanying low grade conjunctivitis
is more apt to occur than in other forms, and it is
more likely to be present in those cases occurring
with oblique astigmatism ; the conjunctival trouble
is made worse by caustics and astringents, and is
often in literature grouped with cases described as
gouty lids, or in some instances among cases of
spring catarrh as an atypical type in which the
31
32 Heterophorias and Insufficiencies.
anatomical signs of true Saemisch's catarrh are
absent.
The marginal blepharitis which occurs in some
cases of increased lacrimal secretion is due to
irritation from the discharge, which runs over the
edges of the lids by day, when they are open, and
also at night because there is a predisposing ana-
tomical condition in blepharitis cases, consisting
of a shortness of the vertical measure of the lids,
compared to the horizontal length, which prevents
proper closure at night. This fact, which has been
strangely overlooked by recent writers on lid in-
flammations, was fully proven by Fuchs and can be
verified clinically with great ease ; the lower edge
of the cornea even may be exposed at night, and
ulcerations in this situation may sometimes be rap-
idly cured by a night bandage, while resisting other
treatment. It is by consideration of the shortened
lids that we understand why relapses occur when
ointments are no longer applied in cases of blephari-
tis marginalis, and why correction of the refraction
or a muscular defect may sometimes permanently
improve the condition by decreasing conjunctival
congestion and lacrimation.
In hyperphoria hyperesthesia retinae and some
nervous irritability are apt to be present. A sign
which should always excite suspicion of hyper-
phoria is a tipping of the head toward the shoulder.
A Clinical Study. 33
The head is tipped downwards toward the right
shoulder in most cases of left hyperphoria and some
of right hyperphoria; in other cases of the latter
anomaly it is tipped toward the left shoulder. The
cause of this tipping is not entirely clear; on first
thought it would seem as if it might occur in order
to bring the eye with the higher image more nearly
on a level with the other, but this fails to explain
all cases. It should be remembered that men are
in the habit of tipping the head toward the right
shoulder in aiming rifles, and also in sighting lines
and objects in many occupations ; the right shoulder
is lower than the left in right-handed people, and I
believe that the sterno-mastoid and other muscles on
the right side of the neck and head are also more
powerful. May not the position of eyes and head
be sometimes due to a common cause ?
The right ear is usually lower than the left and
consequently spectacles sag downward on this side ;
eye-glasses having chains attached to the right lens
also sag in the same direction. That vertically de-
centred lenses are a common cause of hyperphoria
I have little doubt, having known it to occur from
a misplaced glass, in cases where there had been
orthophoria, and disappear after the glass had been
straightened and worn correctly for a time; on the
other hand there is a connection in some cases be
tween the position of the glass and the hyperphoria
34 Heterophorias and Insufficiencies.
which is due to a displacement by the patient in or-
der to correct the deviation and obtain comfort. I ex-
amined at one time glasses made by leading opticians
and found about one half with the optical centre of
one glass above that of the other; there is very
much variation in the number of these errors be-
tween different manufacturers; glasses of a pair
made at different times, as when a broken glass is
replaced, are more apt to be incorrect in this way.
Another certain cause of hyperphoria is muscular
anomaly, which may be a paresis or an excess.
Take a recent case in which I found right hyperphoria
of 5. manifest, 2. latent; right sursumduction 10.,
left sursumduction 2. ; myopic astigmatism .5
right eye, .25 left ; axis of glass 135 and 60
respectively. The left eye seemed to lag behind
in upward movement of the eyes, and there was
diplopia in the left upper quadrant of the field ; in-
sistent questioning regarding diplopia brought out
the statement that the patient thought that she
remembered seeing double about three years ago.
This appears to be a case of paresis of the left
superior rectus, though why a healthy woman of
forty-six years should have developed paresis of an
isolated muscle is a mystery. Investigations upon
injuries to the eyes during childbirth may throw light
upon the etiology of this class of cases as it is now
doing with congenital amblyopia. Another test of
A Clinical Study. 35
the muscles of a woman of fifty-six years with 0.75
D's of hypermetropic astigmatism against the rule in
one eye, 1.50 in the other, and orthophoria, showed
that divergence varied from 10. to 14., convergence
from 13. to 1 6., right sursumduction was 4., left
sursumduction n. This seemed to be a case of
excess of the left superior rectus.
Assuming it to be evident that low degrees of
hyperphoria may be due to misplaced glasses and
high ones to muscular defect, I think I may add
one more positive cause for its production. I
have found a number of cases with the right eye
functionally or optically stronger than the left, in
which left hyperphoria first appeared only upon
convergence, then became manifest with fixation
lines laterally parallel. This I believe to have been
due to the fact that the right eye not only con-
verged more strongly than the left, but also that the
depressor muscles of the cornea were stronger; that
it tended to go below the left first upon convergence,
then permanently; I am sure this is the mechanism
in some cases of convergent squint with sursum-
vergens, and although the squinting eye deviates
upward it is really because the other went below it
in the first instance.
The other causes now to be given to account for
hyperphoria I consider rather speculative. The first
is that when eyes are on a different level the muscles
36 Hcterophorias and Insufficiencies.
become abnormal by attempting to bring the visual
lines on a horizontal plane; this may be an occa-
sional cause, as the two conditions coexist; yet if
there is orthophoria, hyperphoria is not caused by
tipping the head, in the few cases that I have studied
in order to note the effect of difference in level of
the eyes upon the ocular muscles, which brings us
to the connection between hyperphoria and wry neck.
In hyperphoria the head is inclined to the side
with a twist, the base line (between the centres of
rotation) sharing in the inclination ; in the limited
observations of spasmodic wry neck I have made,
there was a more or less successful attempt to adjust
the eyes (having no hyperphoria) by bringing them
up on a horizontal line by giving a compensatory
twist of the head away from that of the neck.
The head tipping in hyperphoria causes lateral
curvature of the spine; the mechanism is perfectly
apparent ; I have seen such cases, and I think they
occur somewhat frequently. The present methods
of keeping a child's head straight in school work,
and the introduction of vertical script do not meet
the conditions in hyperphoria any more than in cer-
tain cases of astigmatism, and may in some instances
result in the very troubles they are intended to
prevent.
The next speculative consideration in the produc-
tion of hyperphoria is optical. That anomalies of
A Clinical Study. 37
the elevator and depressor muscles of the eyes may
change the axis of astigmatism by a rotary action of
the cornea in some instances may be true, but that
does not account for the production of the hyper-
phoria. I have looked over one thousand cases
tested for refractive and muscular errors in the last
three years and find 465 (46.5 %) with oblique astig-
matism ; all other refractive errors 535 (53.5 $). By
oblique astigmatism I mean with the axis not ex-
actly vertical or horizontal, and the above proportion
is about what I have found in my cases for many
years. If the cylinder gives no better vision at an
oblique axis than when straight, or than a spherical,
the case is not counted as oblique astigmatism.
Hyperphoria occurred in 20.8% of all cases; in the
oblique astigmatic cases 26.6$, in the others 14$.
Hence there is evidently a connection between an
oblique axis of astigmatism and the production of
hyperphoria. There were nearly double the number
of hyperphorias in women that there were in men,
but as the proportion of women to men was not
much less than that, the percentage may be con-
sidered nearly equal. In women right hyperphoria
occurred in general more often than left by about
20%. In oblique astigmatism it was rather more fre-
quent by comparison than in other cases. In men
left hyperphoria was more than twice as frequent as
right, in refractive errors other than oblique astig-
38 Heterophorias and Insufficiencies.
matism the proportion being more than 2.5 to i.
The explanation of the more frequent occurrence of
left hyperphoria in men has been already touched
upon. Men are more right eyed because of their
habits and training than women (about half of whom
are so binocular that they cannot wink), and have
more tendency to depress the right eye. If men
and women with better vision in the left eye, and
women with equal vision in the two eyes are elimi-
nated, the proportion of left hyperphoria to right
perceptibly rises; this is even more apparent if left-
handed persons, who use the left eye in shooting,
are also left out of the count. It is perfectly evi-
dent from a study of these cases of hyperphoria,
leaving out the purely muscular cases, which may or
may not cause torsion of the vertical meridian, that
there is a class of cases caused by oblique astig-
matism. There are three ways in which this may
be explained; first by inco-ordination of muscular
action ; second, by an attempt on the part of the
rotating muscles to change the axis to a better po-
sition; this latter explanation seems plausible until
it is applied to the cases singly, when it is seen to
be inapplicable to many. Some of these hyper-
phorias disappear with the proper correcting glasses,
and the disappearance is not always due to pris-
matic action, although this is hard to eliminate;
a third way to explain the combination we are
A Clinical Study. 39
considering is to suppose that in some of these cases
the muscles are normal, but the vertical deflection of
light caused by difference in the height of the
corneal centres gives the vertical displacement
shown by the test, which is optical, not muscular.
This idea has a practical side, which is that oblique
cylinders can be sometimes adjusted so as to cause
hyperphoria to disappear, and that accuracy in find-
ing exactly the proper axis of a correcting cylinder
is an important consideration.
Latent muscular trouble is like latent hyperme-
tropia. It is that portion of the ocular error which
the observer fails to find ; what is latent at one time
to one man is manifest to another under other con-
ditions. When the amount of hyperphoria equals
the difference between right and left sursumduction
it is usually all manifest ; when hyperphoria is less
than this difference, there is probably some of it
latent, which is likely to become manifest later.
This sounds correct, and has proven so to my mind,
but it presupposes a diagnosis of hyperphoria, which
is not always easy to make. It is my purpose to
present as nearly as possible a composite picture
of the more frequent and ordinary weaknesses of
muscular action, since neither the writer nor reader
could stand a detailed statistical description of some
thousand cases ; an occasional history to emphasize
the rule by showing the exception, or to illustrate
4O Heterophorias and Insufficiencies.
the occurrence of what is frequently denied to exist,
seems to be indicated. I used to share in the sneers
of my medical friends regarding latent hyperphoria
even after being convinced of the frequency and im-
portance of the trouble itself. In June, 1892, a boy
of thirteen years who had been under the care of a
careful and competent ophthalmologist and fitted by
him two years before with sph. .5 O c yl- -5
changed to me as a matter of convenience. Under
atropine I found myopia of 2.50 with myopic astig-
matism of i. in addition, vision = f$; there was or-
thophoria with prism convergence at 20 feet of 16.,
divergence 7. A diagnosis of slowly progressing my-
opia with congestion of the choroidal and conjuncti-
val vessels was made and some asthenopia which was
present seemed natural under the circumstances.
Although the myopia and astigmatism increased
only about 1.50 in the next two years, still the cho-
roidal condition in connection with it was held to
fully account for the increasing hyperesthesia of
the retina, and with changes in the nasal mucous
membrane for the lacrimation and recurrent attacks
of follicular conjunctivitis, which latter came on
several times in the two years and were apparently
successfully combated with astringents, although
treatment of the nose was instituted during one
attack before it began to yield. Vision by this time
hovered about f$, being usually rather below this,
A Clinical Study. 41
and the headaches and eye weakness had increased
so that the boy was kept out of school and not per-
mitted to go into business. Twenty-seven months
after I first saw him he came into my office suffering
from an exacerbation of his trouble, which was by
now pretty constant as regarded lacrimation and
severe headache, and as he attempted to look at me
with his congested eyeballs some sort of a chemical
change occurred in my memory cells which insisted
to me that there must be hyperphoria here. A test
with the Maddox rod showed i^ (old style) of right
hyperphoria, which is usually more potent for mis-
chief than left hyperphoria. A little coaxing
brought out 2 the next day, and prisms of .75 were
ordered in each eye, base down right eye, base up
left, with the sphere-cylinders as before. The re-
sult was cessation of headache and decreased
conjunctival congestion and lacrimation almost im-
mediately ; the patient read f $ -f- with either eye
one week later and went into business; had one
headache in a year, but found that he had fever at
the same time and went to his family doctor. In
eighteen months all elements in the glass were
slightly increased in strength, the prism now being
i. o. u. Two and a half years after this, Septem-
ber, 1898, the eyes began to be uncomfortable again,
and examination showed V. = f$ with sphero-cylin-
ders slightly increased in strength, right hyperphoria
42 Heterophorias and Insufficiencies.
3.50. In the glass ordered prisms were increased to
1.50 each and the patient told that should his head-
ache return after a time an operation would be indi-
cated, as stronger prisms would not do as well as the
others. I have heard of the patient once lately
and he was reported comfortable. This is a case of
hyperphoria which had been latent to me; to some
men all hyperphoria is latent.
There is some interest taken in the usual course
of hyperphoria ; it shares with some other things a
tendency to appear or disappear, increase or de-
crease or remain stationary. It usually increases,
and I doubt whether the high amounts ever disap-
pear without operation, unless they are caused by
transient paresis of an ocular muscle.
Hyperphoria of .25 should, I think, be ignored,
and I wish I could say the same of hyperphoria of
.50, but this causes occasionally some trouble, de-
pending upon the sensitiveness of the patient and
weakness of sursumduction ; thus, if sursumduction
shows respectively I. and 1.50, a deviation of .50 is
apt to cause discomfort. Larger amounts are potent
sources of mischief until among the higher grades
some of them become strabismus sursumvergens and
muscular asthenopia becomes improbable. It is well
to correct the manifest hyperphoria entirely with
prisms, or only leave .25 or .50 uncorrected, up to an
amount of 2 Ds. From 2.50 to 3.50 or above from
A Clinical Study. 43
three fourths down to two thirds may be corrected.
In hyperphoria of 3. and upwards it is better in gene-
ral to operate, but it is often convenient to try prisms
in order to note the effect and convince the patient
of the necessity for operation when more hyper-
phoria becomes manifest, as it is likely to do in a
year, more or less. If manifest hyperphoria of i.
or less is to be corrected, I order the prism over the
eye with poorer vision, and in cases with equal
vision over the left. This leaves a chance to change
only one glass when increased prismatic correction
is indicated at a later time. Correction of 1.50 or
over it is well to distribute between the eyes, base
down over one, base up over the other, unless the
deviation is decidedly limited to one eye. Other
indications for varying the position of the prisms
are limitation of upward or downward movements,
use to be made of the glass, and other minor
considerations. Take for instance the common
condition of left hyperphoria with I. of hyperphoria
with the rod over the right eye, 1.5 when it is over
the left eye. In this case the right eye is more used
to fixing, and were it a case of squint the left eye
would deviate. A prism of I. base up right eye in
such a case would be likely to cause more difficulty
when first worn than one of 1.50 base down left eye,
for obvious reasons.
It is easy to demonstrate the necessity of vertical
44 Heterophorias and Insufficiencies.
prisms in many cases; if the prism correcting the
hyperphoria is placed over one of the glasses correct-
ing the refraction, then reversed, most patients can
tell which direction is comfortable and which dis-
tressing without any hypnotic suggestion.
It is usually presupposed that there is an error of
refraction to correct in considering the ordering of
prisms. If no correcting glasses are needed it would
be better to operate in suitable cases, as many pa-
tients cannot be depended upon to wear glasses
which do not help vision, even when symptoms are
relieved by them. I have seen simple vertical
prisms dropped in a case of hyperphoria because the
headache was better; two years later the child af-
fected was under treatment for lateral curvature of
the spine. The headache returned after a time but
the glasses seemed if anything to make it worse;
inquiry showed that one prism had dropped out of
the frame and been replaced with the base in the
same direction as the one on the other side. This
sort of thing is of frequent occurrence and produces
curious consequences. A patient of mine aged
eighty -two had hyperphoria of 3.50 and had suffered
all her life from severe and frequent attacks of head-
ache, with nausea and vertigo; measures for her
relief had proved futile, the condition being de-
scribed as " very bad for the last thirty years." I
introduced prisms into the corrections for hyper-
A Clinical Study. 45
metropia and presbyopia (+2.75 and +5., with
which latter glass Jaeger No. I could be read up to
8"), which were about the same as were then being
worn. Two months later the old lady reported with
great delight that her headaches were relieved.
Three years later this patient returned with evident
senile hebetude, and upon being asked about the
headache said that the relief had been only tempo-
rary ; it turned out that she had dropped the glasses
for distance, and when told that such a course had
caused the return of the trouble, was very positive
that she did not need any distant glasses, as she
could see well enough without them. Spherical
-f-6. was ordered for near work, with prisms, and
energetic orders given that the distant glasses should
be worn. This energy was not thrown away, for
eighteen months later the patient again appeared
with glasses on and said that her eyes were trouble-
some still; the young lady who now accompanied
her corroborated this by saying, " Yes, grandma's
eyes are uncomfortable, and she does not see well
either." The old lady was wearing constantly the
-{-5. formerly given for near work.
Prisms are very successful in relieving asthenopia
and headache when properly applied in hyperphoria
cases, yet sometimes fail when the vertical trouble
is secondary to a lateral deviation, or when with
vertical and lateral deviations the latter is causing
46 Heterophorias and Insufficiencies.
the symptoms. Some ophthalmologists ignore hy-
perphoria altogether in corrections, while others al-
ways correct or operate upon it first, knowing the
dire consequences which sometimes follow the oppo-
site course. It is safer to correct the hyperphoria
first in doubtful cases, and watch the effect upon the
lateral muscles ; if the vertical deviation is small in
amount proportionately to the lateral and only occurs
with esophoria or exophoria as the case may be, and
not in the centre of the field, it may safely be set
down as secondary. In a case of hyperphoria of
this type with severe and constant headache, which
had remained after careful correction of the refrac-
tion under atropine and trial of various vertical
prisms during a year, I took out the prisms, gave
the less hypermetropic correction without atropine
at a first examination, as there was exophoria, and
the headache quickly subsided unless near work was
done, then after a time entirely. My colleague of
a neighboring city, who had been so carefully study-
ing and treating the case before he came very prop-
erly to the question of operation, would be a little
surprised, perhaps, if he knew how easily relief was
obtained.
In considering the relative importance of the ver-
tical and lateral deviations it may sometimes be ad-
visable to order an oblique prism. I have this day
seen a patient who was wearing a prism base out
A Clinical Study. 47
over one eye, base up over the other. An easy way
to figure an oblique prism is to take some unit of
measure (as a centimetre) and draw a vertical line
with the same number of units as the number which
marks the strength of the prism desired to correct
the hyperphoria. At the end of this line another
at right angles is drawn with the number of units
corresponding to the horizontal prism desired, then a
parallelogram constructed. Keeping the direction
of the prisms in mind, a diagonal line is now drawn
from the corner where the apices would meet to that
between the bases, which in the units of measure
will show the strength of the oblique prism, and by
its direction the axis. This oblique prism is the
exact equivalent of the combination of the two
others.
In operating for hyperphoria, tenotomy of the
stronger superior rectus is usually done, for what
seem to the writers upon the subject good and suffi-
cient reasons. I have not as yet had to advance an
inferior rectus except in cases of strabismus. In
order to do the operation the eye is rendered super-
ficially insensible to pain by cocaine or holocaine.
I use the latter because it penetrates more deeply
and has no effect on the circulation and pupil.
There is apparently less secondary subconjunctival
hemorrhage and oedema than from cocaine, but I
have seen many more attacks of faintness following
48 Heterophorias and Insufficiencies.
its use than I ever saw after cocaine, so I incline to
think it more toxic and have whiskey close by when
I use it. After the eye is flushed with neutral salt
solution the upper lid is supported by the ring finger
of the left hand, which holds a pair of fine-pointed
forceps between the forefinger and thumb. The little
finger is understudy for the ring finger, the middle
finger goes with the forefinger. As the eyeball is
directed downwards the conjunctiva is grasped over
the middle of the insertion of the superior rectus
muscle, and with the tenotomy scissors in the right
hand a cut is made. Through this the centre of the
muscle tendon is grasped by the forceps and cut ;
from this laterally cuts are made, with the tendon
grasped between the blades of the scissors, until
orthophoria is obtained, the eyes being tested after
each cut. A bandage should be worn, for comfort
and to control hemorrhage, but a few hours; if the
patient then uses the eyes the full effect of the
operation may remain, or may be kept by forcing
downward motion. The deviation may partly re-
turn, one third of the original being the most I have
as yet seen come back, but allowance cannot be
made for this without risk of over-correction. In
this tenotomy there is usually a scarlet-looking eye
by the second day, as the blood under the conjunc-
tiva settles downwards on both sides over the sclera ;
the main trouble I have experienced from this
A Clinical Study. 49
operation has been annoyance from the complaints
concerning the red eye from patients and their
friends. The fine-bladed scissors of Stevens I have
had to give up after trials of several pairs; they
tangle up in the muscle fibres and do not cut cleanly
through them when the muscle is well developed,
and considerable effect is desired, as in most cases
upon which I operate.
CHAPTER III.
ESOPHORIA.
DESCRIPTIONS of that type ot headache
called migraine all need to be remodelled
from the standpoint of recent knowledge of eye
strain, and especially with reference to the type of
headache occurring from esophoria. The only
headaches of the " sick headache " type which are
extremely unlikely to occur from esophoria are those
in which gastric or intestinal disturbances of a marked
type precede the headache, and this occurs in the
form of very severe hemicrania ; in this type of head-
ache there is sometimes a suspicion of some station-
ary and chronic change in the bones of the skull,
causing pressure or irritation of the brain, its mem-
branes, or its blood-vessels, in which case paresis of
an external rectus muscle may occur with the head-
ache attacks. Possibly spasm of convergence may
occur from irritation of the convergence centre in
migraine cases, but it is rare. A good illustration
of a form of sick headache not due to ocular anomaly
may be found in cases of arterio-sclerosis ; these
50
A Clinical Study. 5 1
latter headaches increase with age and are to be
differentiated not so much from the headaches of
esophoria as from those of exophoria.
The regular history of the headache of esophoria,
which is uncomplicated by other forms of eye error,
is that it is periodic, and accompanied by dizziness
and nausea. Its occurrence may be usually traced
to prolonged use of the eyes in distant vision ; thus
it occurs after attendance at a theatre and is apt to
be referred to the close air ; after shooting at a rifle
range, when it is supposed to be due to exposure to
draughts of fresh air; after a course of art study or
the like, when it is known to come from lack of exer-
cise ; after bicycle rides, when it is considered evident
that it is due to too much exercise. During or
preceding the attacks the latent esophoria is apt to
become manifest, and in some cases, whether mus-
cular or accommodative, homonymous diplopia may
result. In most cases of headache from esophoria
the trouble tends to diminish toward middle age as
the interni become weaker and the refractive error
becomes manifest ; and this result is referred to all
sorts of causes except the real one, which is spon-
taneous improvement or disappearance of the
esophoria.
It must be kept in mind in all cases of heterophoria
that there may be no symptoms at all (in which case
the deviation requires no treatment,) or all of the
5 2 Heterophorias and Insufficiencies.
usual symptoms, or any combination of them. It
has happened to me to observe much dizziness, with
or without nausea, from esophoria, and more cases
of vertigo in this than other heterophorias; in fact
this and hyperphoria have so far furnished the few
cases of vertigo with falling that I have seen relieved
by eye treatment.
Accommodative Esophoria. Esophoria with Hy-
permetropia. Esophoria is usually accommodative
and due to spasm of convergence, accompanying
spasm of accommodation, in uncorrected hyper-
metropia. When i. or less it may be ignored ex-
cept in cases of neurasthenic muscular asthenopia
with weak action of the interni and externi ; in rare
cases esophoria of i. or less may be due to false pro-
jection, the eyes converging for 20 feet and the
mind projecting the images to infinity. In many
cases of accommodative esophoria in young people
the case may be diagnosed with ease. Divergence
is not below normal, and when a proper correction
for hypermetropia is put upon the eyes orthophoria
or even exophoria and excess of divergence may im-
mediately result, or develop after the glass correction
has been worn for some time.
In view of the peculiar expression some ophthal-
mologists have at the mention of esophoria with in-
sufficiency of the interni or excess of the externi,
as well as the peculiar statements in some quarters
A Clinical Study. 53
about the lack of effect upon convergence through
the accommodation, let me present the case of a lad
who came into my office a few days ago and saved
me the trouble of deciding which of the many cases
among the histories of such should be described, as
I do not expect any other to present a more marked
example of divergence excess and esophoria. The
boy's age is sixteen, and +2.75 spherical is being
worn. There is -|~4-5O of hypermetropia, and .50
of astigmatism in addition, with better accommoda-
tion in the right eye than the left. V. = f$, R. E.,
f$, L. E. At 20 feet there is an esophoria of 4.5,
convergence 20., with forcing after instruction and
practice 35., a little left hyperphoria with conver-
gence. Divergence 15. The convergence near point
is 5 inches, at which distance the eyes begin to
diverge, although by an effort fixation can be recov-
ered and the eyes forced to converge nearer. Exo-
phoria at 13", 4 D's. With full correction of the
refraction there is orthophoria, divergence still 15.,
convergence not so good as without the glass. If I
may judge by experience these eyes will have exo-
phoria before long, and perhaps divergent squint
later, although without proper correction of the re-
fraction there is now periodic convergent squint
which the patient has observed. These cases should
be treated for the accommodative esophoria first by
correcting the refraction, later for the exophoria and
54 Heterophorias and Insufficiencies.
excess of the extern! by tenotomy of the latter
muscles; always provided there is muscular asthe-
nopia or the condition is passing into strabismus.
The diagnosis of accommodative esophoria is not
always easy. As time goes on in these cases, if the
refraction is not corrected, divergence becomes
weaker and may be as little as 5., seldom lower. It
may well be asked why divergence of less than 5.
should be arbitrarily given as not belonging to ac-
commodative esophoria when it is well known that
convergent squint is often if not usually of accom-
modative origin. It seems to me that in cases
where the desire for binocular fixation is so strong
that it will allow esophoria only to result, and where
the spasm of accommodation and convergence ex-
cept for this desire would cause squint, the externi
would hardly fall below a standard of power suffi-
cient to insure binocular fixation, with a margin left
for emergencies, unless they were insufficient ; for
practical purposes, divergence of 4. or less should be
considered as a muscular insufficiency, unless conver-
gence is also correspondingly weak, when the case
belongs to another class to be considered later.
All cases of esophoria with headache, dizziness, or
nausea after use of the eyes for distant vision, in
which the muscular deviation does not yield to cor-
rection of the manifest hypermetropia, should (un-
less surely myopic) be put under atropine. In
A Clinical Study. 55
certain young persons, with a moderate amount of
hypermetropia and spasm of accommodation which
entirely conceals the refractive error, there is eso-
phoria with periodic headaches, accompanied by
dizziness and nausea, which are relieved by correct-
ing the refraction as shown under atropine less .25
or .50; after a time the esophoria disappears entirely
and the glass is dropped without a return of the
symptoms. A certain amount of the hypermetropia
I consider the artificial production of the atropine ;
some patients may bear the full correction found
under atropine, but more do not; if a correction is
given which does not allow of clear distant vision
after the atropine is no longer used, the patient,
especially if still in the years of childhood, is likely
to look over the glasses for distant vision and thus
defeat the desired effect upon the muscles through
the accommodation. The effect of accommodation
upon convergence depends upon structural or edu-
cational connection between the centres in the brain,
and is very variable in different people.
It may be of interest to know the slow mental
processes by which the writer arrived at some of these
conclusions which he has set forth. Under an able
and thorough chief, during some years I tested the
refraction of several thousand patients under atro-
pine; as time went on and I found that the tests
without atropine tallied with those found or
56 Heterophorias and Insufficiencies.
expected under atropine, the use of the drug was
dropped. Certain cases did not do as well as re-
garded the asthenopia and headache as formerly,
when atropine was used, and after rinding that this
resulted when the glasses were of no different
strength, and after eliminating the question of rest
to the ciliary muscle as an explanation, I found that
this result was due in certain cases to the relaxation
of accommodative esophoria, and began to use atro-
pine in esophoria cases again, as I had always
properly been taught to do in cases of convergent
squint.
A few cases show more esophoria under atropine
than before its use. Duane has explained that this
is due to extra efforts of accommodation induced by
attempts to contract the ciliary muscle. Reason-
able as is this explanation, I am not prepared to
accept it ; long ago, in the case of a child with con-
vergent squint, in which atropine increased the de-
formity, the mother told me that she had noticed
increase of the squint when her child was excited
or agitated, and that the girl had been very angry
about the drops, the eyes crossing more just as soon
as she knew that they were to be instilled. I have
been able in the cases under discussion to trace the
result to spasm of convergence, or weakness of
divergence, caused by nervous irritability or ex-
haustion; within a few weeks I had this occur, my
A Clinical Study. 57
patient, a neurotic woman of forty, being in a very
excited state because the atropine had dried her
throat and kept her awake; at the beginning of the
examination under atropine esophoria had increased,
but at the close when the patient's excitement
had gone down the esophoria had decreased with
it.
Cases of accommodative esophoria may occur up
to the age of fifty-five years. In hypermetropic
presbyopes with esophoria spasm of accommodation
may be suspected when the glass required to correct
the presbyopia is stronger than usual. In cases of
accommodative or spasmodic esophoria operations
are, of course, contra-indicated, although frequently
performed. It is in just this class of cases that
tenotomy of the interni does the most harm. If it
is doubtful whether the case is accommodative or
muscular, and symptoms are not relieved by mere
correction of the refraction, prisms of just sufficient
strength to bring divergence up to the minimum for
that case (6. or 7.) may be given. It may be some
years before relaxation of the interni in these cases
causes the esophoria to disappear, but it usually
occurs, sooner or later.
In accommodative spasm, as in any other spasm
(if such exist) of the interni, strychnine, rest, and
general tonic treatment often increase the esophoria
and the ocular symptoms.
5 8 Hetcrophorias and Insufficiencies.
It would be very erroneous for any one to sup-
pose that the typical symptoms of esophoria head-
ache, dizziness, or nausea, with a tendency to
periodicity occurring after prolonged use of the
eyes for distant objects are usually met with un-
accompanied by other ocular disturbances. In ac-
commodative esophoria especially are there often
other disturbances due to other ocular conditions ;
thus hypermetropia and astigmatism may cause
frontal and temporal headache for distance and near
work, and as in some other forms of esophoria, in-
sufficiency of the interni, or of convergence, may
cause asthenopia when near work is done, and
intense and constant headache may occur when
esophoria at the reading distance is present, which
error may be greater than that for distance.
Esophoria of Habit. Esophoria with Myopia. My
attention was first attracted to this class of cases in
June, 1894. A young lady of twenty-three years
came to me with the statement that she saw double
at times, and that all glasses given to her heretofore
caused much dizziness and discomfort. There was
myopia of 2.25 with a little astigmatism. Eso-
phoria of 8. increased to 12. with the glass (2 D.)
now being worn; convergence 25., divergence 5.
At 13* esophoria 5., convergence 45., divergence
1 1 . After atropine no change in refraction , esophoria
9., convergence 38., divergence 6. There was
A Clinical Study. 59
apparent divergence; especial note should be made
of this; in myopia with esophoria there is apt to be
apparent divergence and the glasses are often centred
too broadly, while in myopia and exophoria there is
usually apparent convergence and the opposite error
-ef~toe great an .,o...c. in the glasses often occurs.
Glasses were ordered in this case with prisms 1.50
o.u. base out and o.c. in proper position; in other
words, 3 D's of prismatic action at the fixation lines.
These glasses caused no discomfort from the first,
but three months later the patient asked if she could
not have a less clumsy glass, as the thick outer edges
of the present one attracted attention. Esophoria
was now 6. This was accomplished by making the
p.d. narrower, the centre of glasses being 3 mm.
inside the lines of fixation, and no prism ordered.
Three weeks after this the left eye having a little
neuralgic pain when the glass was worn, esophoria
was found to be down to 2. without any glass, and
also with the last glass. The discomfort subsided
shortly after, and the patient brought in her mother,
who had high myopia and convergent squint, the
eyes converging for the far point of accommodation,
which was 2^" from the root of the nose, and not
diverging for distant objects. Convergent squint
with myopia had before this excited my interest,
and after concluding that it resulted from the habit
of fixing near objects, I found that this explanation
60 Heterophorias and Insufficiencies.
and no other had been given by all writers who had
considered its causation.
After this esophoria and myopia attracted my at-
tention, and soon after I had an opportunity to
treat two sisters with this combination; one had
already had twelve operations done in the vain en-
deavor to straighten the eyes, the only result having
been much fatigue to the nervous system ; the other
had long been troubled with dizziness and had been
treated for " the liver " without relief to that symp-
tom. In the latter case, as the decentred lenses
ordered seemed to cause asthenopia, I ordered prisms
for the same muscular effect (combined with the
correction for the refraction, practically the same
that was being worn before I saw the case), and the
dizziness subsided slowly, disappearing within a
month. It returned about three years later, when
it was found that orthophoria was present instead
of esophoria of 3., and the prisms of I. base out were
taken from the glasses, when the dizziness and
asthenopia again disappeared. In the case of the
first sister there was esophoria of /., right hyper-
phoria of i., and it is not necessary to narrate the
details of the glasses decentred inwards, and the
good effects, except to say that in three years
the hyperphoria disappeared, as it was a converg-
ence hyperphoria, and esophoria was I. instead of
7. The father of these girls has hypermetropic
A Clinical Study. 61
astigmatism and orthophoria, the mother has com-
pound myopic astigmatism and no appreciable devi-
ation, and another sister has myopic astigmatism,
with a little exophoria and excess of divergence.
Since these cases I have treated several scores of
others with myopia and the esophoria of habit, all in
the same way. This includes cases in which I had
formerly failed to appreciate the condition. As a
rule convergence is not excessive, and there is some-
times asthenopia for near work from insufficiency of
convergence; there is a fairly definite relation be-
tween the amount of myopia and esophoria; I de-
centre the glasses from 2 to 4 mm., so that there
is prismatic action at a distance with the prisms base
out, and usually some prismatic action in the oppo-
site direction for reading distance. This is not done
at haphazard ; the object is to get the least prismatic
action that will cause comfort to the patient, in the
expectation that improvement or cure of the devia-
tion will result as the eyes become accustomed to
fixing at a distance. The trouble occurs in persons
who have gone with their myopia uncorrected in
youth ; the symptoms in some cases do not begin
until glasses are worn, and may pass off without
any especial attention to adjustment of the lenses,
although not infrequently they persist. The most
usual symptom is dizziness with distant glasses,
occasionally headache, and I have seen one case of
62 Heterophorias and Insufficiencies.
conjunctival congestion and blepharitis marginalis.
In this latter case a patient whose refraction had
been corrected returned to me because of increas-
ing eye strain. For the esophoria, which had pre-
viously been ignored, appropriately centred glasses
were ordered. I had no chance to verify the cor-
rectness of their manufacture, and nearly a year
later my patient returned, complaining that the
glasses had done him no good. The feeling of
strain and the lid trouble were worse, and I found
that his optician had taken the liberty of correcting
my error about the centre, or paid no attention to
the directions ; I saw that the lenses were decentred
as I wished, after which the symptoms promptly
subsided, and the lid congestion as well.
It will be noticed that a distinction was made in
two of these cases between prisms and decentred
lenses; I have given up any attempt to keep up
such a distinction in clinical work, except for certain
purposes, as when I find it much easier mentally, as
above shown, to fit a decentred lens than figure
prisms, or when, as in the case where vertical pris-
matic action is desired, I order prisms instead of
decentred lenses because I find this method easier
as well as more likely to insure correctness in the
work of the optician. The decentred biconvex lens
portrayed in books which state that such a glass is
equivalent to a prismosphere is dissimilar to the
A Clinical Study. 63
glass ground by the manufacturers when spheres
and prisms are ordered in combination, as the latter
has one plane surface and may be considered as a
decentred plano-convex or concave lens. It is cer-
tainly wrong to consider such lenses as identical,
or a decentred meniscus as the exact equivalent
of either ; the differences are not only optical,
but prismatic as well when the eyes are turned
toward the periphery of the glass, yet the pain in
one eye caused in the patient above mentioned
when prisms were replaced by decentred lenses
should be referred to the different position of the
weak oblique cylinder in the lens, or some optical
influence, rather than difference of prismatic action.
It is only by consideration of such points that re-
ported cases of asthenopia relieved by toric lenses
in place of the usual kind, or a change of frames for
the glasses, can be given any value.
In muscular asthenopia we are dealing largely
with subjective symptoms caused by variation in
physiological and anatomical conditions; the con-
servative observer, until he or some member of his
family suffers from severe muscular asthenopia, is
apt to remain somewhat skeptical regarding the im-
portance of these difficulties, to regard a necessarily
artificial classification with some suspicion, and may
question the propriety of the introduction of a sepa-
rate class for cases which it might seem possible to
64 Heterophorias and Insufficiencies.
include under old headings by means of some elas-
ticity of distribution ; yet the myopic esophoria of
habit has strong claims for recognition as a clinical
entity ; when it is recognized and considered in
glass corrections it is easily treated and benefited ;
when not, the fatigue of the externi often continues
and the symptoms may go on from bad to worse.
The esophoria is out of all proportion to the weak-
ness of divergence, and exceptionally may be in-
creased by stimulation to the accommodation when
concave glasses are worn. Thus it will be noticed
in a test given above that esophoria of 8. increased
to 12. with the correcting glass, while divergence of
6. remained unchanged. It will also be noticed that
prism i. only was ordered ; I never order a prismatic
effect in such cases which increases divergence to
more than 8. no matter what the esophoria. I fol-
low the same rule in all forms of esophoria, but in
no other is there any such disproportion between
esophoria and divergence after correction of the
refraction as in the esophoria of myopia. It must
always be kept in mind when prisms are ordered
that the prism strength is added to the muscular
power in the direction of the base and deducted
from that in the direction of the apex.
Passing over a considerable number of these cases
which present no special features it may be proper
to present a case with a fairly complete history
A Clinical Study. 65
which showed the deviation and its effect to a
marked degree ; in view of the astigmatic element in
some of these cases it may be well to state that a con-
siderable number had the condition, the symptoms,
and the results without any astigmatism being found.
A hard-worked financier of forty-eight years had
been ordered sph. 9. right eye, 8.50 left, in
the spring of 1898, by a careful ophthalmologist of
high standing. He had signs of nervous fatigue
with some dyspepsia, but his most troublesome
complaints were of headache, mostly posterior and
basilar, and attacks of vertigo, without falling, when
attempts were made to look at distant objects.
His physician, having found no relief to his symp-
toms after a summer's vacation, concluded to resub-
mit him to an eye examination, and I saw him in
October, 1898. Vision with the old glasses (62 mm,
o.c.) wasf$ o.u. With 9. 50 and 9. ^cyls. i.
and .75 axis 90 in the right and left eyes respec-
tively V. = $- -f- in each. The eyes without glasses
showed an indeterminate amount of esophoria and
convergence; divergence I. and homonymous diplo-
pia under a red glass. There was right hyperphoria
of i., but the natural sag of the glass corrected this.
It was found that with the glasses at 56 mm. o.c.
orthophoria was at least temporarily present, and
they were thus ordered, a near glass less the presby-
opic correction being ordered with o.c. at 60
66 Heterophorias and Insufficiencies.
as convergence was weak. This was done without
making unnecessary tests, as the already prolonged
examination had pretty well exhausted the patient.
The glasses caused much distress at first, but this
wore off, and the vertigo and severe headache were
relieved within a week. Nine days later the eyes
with the glass on showed for distance orthophoria,
with convergence 20., divergence 7. It is well to
note that the prismatic action of the glass upon the
eyes was 4., and also to call attention to the fact
that the hyperphoria was no doubt one cause for the
inco-ordinate action of the muscles of the eyes with-
out glasses, and perhaps had a contributing influ-
ence in producing symptoms; as to the astigmatism
as a cause of the vertigo this was thrown out, since
a duplicate pair of glasses were made later by the
patient's optician at 60 mm. o.c. and they brought
back the vertigo quickly; another similar mistake
was made later, with the same result. When the
eyes (or externi) were fatigued, as after attendance
at theatre, the esophoria partly returned with a
feeling of ocular fatigue, and about 2. of esophoria
could be found the next morning (with the glass
worn). This patient had clonic blepharospasm on
the left side and I treated his conjunctivitis and
blepharitis ; when this failed to relieve the twitching,
as a little more astigmatism had become manifest in
the left eye, I ordered a cylinder .25 stronger for
A Clinical Study. 67
that eye. In June, 1899, the patient returned, as
he had begun to have some increasing discomfort
from his eyes, and he had been warned to expect
that as his esophoria disappeared ; he reported that
his blepharospasm, headache, and dizziness had re-
mained away after the last glass was worn, and his
ability to read without fatigue had gradually im-
proved. I found hyperphoria 2. (i. being corrected
by the glass). With the glasses on there was now
exophoria of 2., divergence of 10. New glasses
were ordered at 60 mm. o.c. with vertical prism I.
(base up, left eye), and the patient told to report if
not entirely comfortable. This case is the only one
seen by me, except the first one mentioned, in which
periodic squint with diplopia occurred and the only
one in which hyperphoria increased during the time
the case was under observation.
Full correction of the refraction is indicated to
give the best distant vision and stimulate proper
binocular fixation at a distance, and operations are
contraindicated in the esophoria of habit, which
occurs always, or nearly always, with myopia.
Muscular Esophoria. Esophoria from muscular
causes is due to excess of the interni or insufficiency
of the externi, and may occur with any or with no
error of refraction. In the first condition conver-
gence is powerful, divergence may be secondarily
omewhat weak, nervous irritability or strychnine
68 Heterophorias and Insufficiencies.
increases the defect, and there is esophoria also for
near points unless insufficiency of convergence co-
exists. It may have been noticed that a distinction
is made between insufficiency of the interni and
externi, and insufficiency of convergence and diver-
gence; by the first terms I mean that there is a
muscular defect, by the latter a deficiency, shown
by the tests, of an associated action, which may be
muscular, nervous, or secondary to an error of re-
fraction. For instance, insufficiency of convergence
may be due to optical, accommodative, or general
nervous causes, excess of the externi, fatigue, or
insufficiency of the interni. Whether the oft-
mentioned spasm of convergence occurs without
excess of the interni, or insufficiency of the externi,
except in general disease, as meningitis, hysteria, or
chorea, or from local conditions, as from hyper-
metropia, hyperphoria, or improper glasses, is some-
what doubtful. There are rare cases which show
good balance of the ocular muscles and normal
divergence at times, which at others show esophoria
and weak divergence. Probably these are mostly
instances of latent esophoria becoming manifest,
like the other more numerous cases in which eso-
phoria is increasediunder just such general conditions.
It would be as rational to refer them to exhaustion
of divergence as spasm of convergence, the excess of
convergence being*simply a secondary result.
A Clinical Study. 69
In cases of esophoria and excess of convergence
it is well to treat the deviation with caution, espe-
cially when hypermetropia coexists, using atropine
and attempting to relax the interni ; over-correction
of hypermetropia, or convex glasses for reading in
non-presbyopic cases, I do not particularly favor,
although the latter plan may sometimes be followed
with benefit. Prisms do well in the proper cases;
those in which the insufficiency of divergence and
the esophoria practically agree, and the muscular
condition for far and near are similar and prisms of
from i. to 2. over each eye nearly correct the diffi-
culties. In such cases three fourths or even all the
deviation may be corrected, the prism being ordered
in combination with the glass properly correcting
the refraction. In cases where the deviation tends
to increase, and prisms having been of relief are so
no longer, a tenotomy of one internus, perhaps fol-
lowed by a tenotomy of the other later, may be in-
dicated. The operation is similarly done to that for
hyperphoria, but usually needs to be complete. In
these operations strength is sacrificed for position,
convergence is usually weakened for a time out of
proportion to the good effect upon the esophoria,
and near work is apt to cause considerable discom-
fort for a week or two at least, even when the opera-
tion was done delicately. After this the severe
headache and symptoms are likely to be relieved,
70 Heterophorias and Insufficiencies.
and although from the nature of the anatomical
conditions the esophoria is prone to return, weeks,
months, or years later, the headache and other
symptoms may not return. I am not conscious of
reason for regret in having done this operation in
the few cases in which I thought it necessary, but I
have treated a considerable number of post-operative
cases after they had passed out of the hands of col-
leagues, and I am not highly enthusiastic about the
results.
Most cases of muscular esophoria are, in my
opinion, due to insufficiency of the externi. Strych-
nine sometimes will help the asthenopia in these
cases; divergence is 4., or less, and convergence is
not excessive. The proper operation is an advance-
ment of an externus, picking out the weaker if this
can be done, as is often possible. The usual ad-
vancement for insufficiency is a detachment of the
central part of the muscle from its insertion, loosen-
ing of the subconjunctival tissue toward the cornea,
and the tightening and tying of a single horizontal
stitch which is passed through the middle of the
muscle near its cut end and the tissue above the
sclera up to the corneal margin. This single stitch
is entirely effective for the readvancement of a teno-
tomized muscle when the effect is too great, but for
cases where the opposing muscle is strong I prefer to
lift the muscle upon a tenotomy hook after making a
A Clinical Study. 7 1
small opening above and below, and then pass the
needles at each end of a stitch through this upheld
fold toward the cornea, grasping conjunctiva and
muscle in a loop which holds more than half the
breadth of the muscle. The stitch is tightened,
and tied when orthophoria is obtained ; the result is
certain and permanent, and no bad result follows
should the stitch cut through, as it may occasionally
after some days. The operation is easy and pain-
less, and the fold in the muscle disappears gradually,
leaving the effect of the operation with no deformity.
Notwithstanding the good points about this advance-
ment it is not likely to come into general use, as it
is not so picturesque as some others at the time
of and immediately following the operation. The
stitch of an advancement should be kept in place
for five or six days, the eye being kept bandaged.
Motions of the eyes are uncomfortable because of
the stitch, and are avoided by the patient while it
remains in position, so I advance, or, strictly speak-
ing, fold, a muscle in my office, using no speculum,
and let my patient go home with a single bandage.
It is absolutely necessary to test the eyes at inter-
vals while doing tenotomies and advancements for
heterophoria, and this cannot be so well done if the
patient does not sit up for the operation in the office.
I find confinement in bed unnecessary.
It will be seen by the above that the old motto
72 Heterophorias and Insufficiencies.
" It is better to be sure than sorry " applies to the
treatment of esophoria. I am in no greater hurry
to operate in these cases as time goes on than I was
formerly, and I am constantly surprised by the im-
provement in, and disappearance of, certain eso-
phorias without operation where such a result could
hardly have been predicted. Any centra-indication
will deter me from operation in these cases, and I
will here mention the case of an ophthalmologist
who had suffered severely for ten years from extreme
asthenopia and headache, mostly temporal and fron-
tal. This gentleman had consulted colleagues in
various cities about his ocular muscles and the last
one had proposed to straighten his physiological
vertical meridian, which tipped a little ; this last
opinion immediately gave me a clue, as I had seen
such cases before. The patient was wearing -\- I.
and 1.25 cyls. axes 90, which he had fitted, and
which all the consultants had accepted without spe-
cial investigation, and he had astigmatism which
was most perfectly corrected by cyls. -|- 1.25 and
1.75, axes 85 and 100 respectively. There was
decided vertical insufficiency of the lids, with con-
junctival congestion and blepharitis marginalis. At
twenty feet esophoria 2., convergence 16., diver-
gence 4. At 13" exophoria 10. and upwards, from
convergence insufficiency ; convergence 25., diver-
gence 14. There was no hyperphoria, and I told him
A Clinical Study. 73
that I was conscious enough of my limitations to let
the muscles alone in all such cases as his, even if the
symptoms were more indicative of a muscular cause
than in this. I ordered the proper cylinder and told
him to treat his blepharitis, for whether the com-
pression theory be true or not, certainly asthenopia
comes from lid irritation in some cases; advised
strychnine to be used for the insufficiency of con-
vergence and the effects noted. The latter treat-
ment had of course already been tried. This
physician followed the first two suggestions, and
reported with apparent delight one week later, be-
fore he left for home, that he and his eyes had not
been so comfortable for years. There was no change
in the muscle test. It is doubtful whether those
eyes now have the comfort and endurance that
would be likely to be present in a case with strong,
well-balanced ocular muscles, yet a moral of a certain
sort may be drawn from the history.
It may be well here to call attention to the fact
that occasionally cases with weak externi momen-
tarily overcome prisms base in far in excess of those
which represent the real muscular power, while
rather more often just the opposite condition obtains
in eyes with abnormally strong externi. For in-
stance the externi may overcome prism 7. or 8. as
the test is first made, yet, in case they are weak,
diplopia quickly results should the prism be kept
74 Heterophorias and Insufficiencies.
before the eyes, after which it is found that weaker
prisms are not overcome ; on the other hand with
strong externi prisms which at first produce diplopia
are overcome soon after, and divergence may thus
turn out to be much in excess of that which a rapid
and superficial test would have shown. This tendency
to concealment of latent deviations results from the
very nature of the case; these eyes are not only
forced into binocular fixation, but necessarily also
in exercising that faculty into a condition which
would be orthophoria if our tests should not succeed
in relaxing the strain put upon the weak muscles.
In measuring muscular ability endurance should be
considered more than temporary strength.
CHAPTER IV.
EXOPHORIA.
THE headache of exophoria may only occur
when near work is done, or is increased by
near work unless there is divergent squint for near
points. It may be frontal, general, or consist of
pain in the posterior cervical region, and be accom-
panied by dizziness or nausea. There may be rapid
exhaustion of the eyes for near work, with or without
headache, from exophoria and weak convergence,
and sometimes the symptoms may be produced by
simple convergence for a near object or tests with
prisms base out. This production of symptoms by
prisms which bring a strain upon the weaker muscles
is not confined to exophoria, but is more easily de-
tected in this than in other deviations. For these
reasons weak convergence was the first of the in-
sufficiencies to be recognized, and has received an
amount of attention not as yet accorded to the more
obscure but not less potential muscular weaknesses.
As will be noted above, the asthenopic symptoms
in esophoria have nothing distinctive of the source,
75
76 Heterophorias and Insufficiencies.
since combinations of other muscular and refractive
errors may cause them.
While divergence as an associated action has un-
doubted claims to a cerebral centre, yet I am posi-
tive that in normal conditions it cannot be forced
beyond a well-known limit set by habit and the
exercise of binocular fixation. I accept unquali-
fiedly the dictum of Hansen Grut that divergence
of the visual lines cannot be produced at will
and when found must result from abnormality, but
that latent divergence is often concealed by con-
vergence which exists both as a voluntary and reflex
act.
Exophoria always means then comparative excess
of strength of the externi, or of divergence (although
not necessarily as a permanent condition), if we keep
in mind the fact that the eyes tested at nearer points
than infinity may not converge for the test distance.
Thus for twenty feet if parallelism for infinity is
present and fixation is for infinite distance, either
through lack of accommodation in myopia or for
any other cause, it will take about a I. prism, base
in, to produce vertical equilibrium. The men who
originally stated that the difference between twenty
feet and infinity could be ignored in testing the
ocular muscles little foresaw that this would some
time be applied to tests with weak prisms.
Exophoria of I. at twenty feet I have often seen
A Clinical Study. 7 7
occur in eyes where every other consideration led
me to consider the action of the ocular muscles
normal; more than that amount represents a real
tendency to divergence, and with exophoria r. only,
manifest, there may be any amount latent.
Accommodative Exophoria. Accommodative ex-
ophoria can only occur with myopia, unless it is
produced by too strong convex lenses in hyper-
metropia, or is acquired in the same manner from
reading glasses in presbyopia. In myopia the
exophoria will only disappear in young persons
when full correction is ordered, and in later life be-
comes permanent, although in an occasional case it
yields somewhat to correction of the refraction in
patients up to the age of forty and a little beyond
it. There is of course no intention on my part to
deny that certain anatomical conditions assist in the
production of exophoria and excessive divergence
in myopic cases. In cases of true accommodative
exophoria there is likely to be little or no increase
of divergence for distance, although prism conver-
gence may not be up to the standard, while exopho-
ria and weakness of convergence for near points are
out of proportion to these conditions for distance.
In fact it is the old, well-known condition of relative
divergence.
These cases are so well known and have been dis-
cussed so often, that anything I have to offer may
78 Heterophorias and Insufficiencies.
be briefly stated. To prevent exophoria and insuffi-
ciency of convergence in myopia the refraction
should be fully corrected ; at a later period full cor-
rection, the glass being worn all the time, will give
stimulation to the convergence and favorable pris-
matic action for near work. Fortunately this class
of cases are not troubled much with muscular as-
thenopia unless there is an evident muscular defect
for distance which admits of operation, an astigma-
tism which admits of correction, or nervous exhaus-
tion of convergence power which needs appropriate
general treatment. Perhaps the following will serve
as a fairly typical case of accommodative exophoria.
An athletic schoolboy, aged fourteen at the time of
my first examination, October i, 1898, had f$ o.u.,
with sph. 1.25 ^ cyl. .5 axis 105 R., sph.
1.50 L. = -. Exophoria 3., no asthenopia.
Further examination of refraction and muscles con-
sidered unnecessary. The glass ordered was only
worn in the schoolroom, and on December 22, 1899,
the myopia had increased to 2.25 o.u., with astig-
matism as before in the right eye. Exophoria 4.
As I supposed this to be a good sample case of ac-
commodative exophoria the muscles were further
tested in order to give the tests here. Convergence
at twenty feet, 12., easily brought up to 25. as soon
as the patient was shown how to converge; diver-
gence, 7. For 13", exophoria 10., 12., or more; a
A Clinical Study. 79
test for the near point of convergence showed fixa-
tion at first at 10", but when the patient was told to
fix his attention and turn the eyes in for the pencil
he had no difficulty in converging to within 3" and
holding the eyes in that position. Cases of this
sort are, in my opinion, exophorias without muscu-
lar insufficiency ; they are more likely to have mus-
cular asthenopia from overwork than those cases of
myopia in which the eye muscles become more
correctly adjusted to the new accommodative con-
ditions, unless binocular fixation for near objects is
sacrificed.
The production of accommodative exophoria by
means of convex glasses is a common occurrence and
can in many cases be avoided. It frequently occurs
from full correction of the hypermetropia found
under atropine, and over-correction of hypermetro-
pia of about .50 in cases in which atropine has not
been used is of no uncommon occurrence. Patients
sometimes accept an over-correction of about .50
when hypermetropic, especially if after each eye is
tested separately the highest correction is forced
with both eyes open, the test letters with the glasses
perhaps appearing somewhat faded or washed out,
although vision is not diminished. I have in this
manner occasionally succeeded in getting a stronger
glass to correct hypermetropia than could be ob-
tained later with the eyes under atropine. Another
8o Heterophorias and Insufficiencies.
class of cases in which accommodative exophoria
occurs are those in which (perhaps under atropine)
the spherical lens which represents the meridian of
greatest hypermetropia, is accepted with vision of
f$, or so, while the addition of a weak concave
cylinder would give better vision. In other words,
there is a small amount of astigmatism, and the
spherical over-correction given results in an artificial
myopic astigmatism. I have noted several cases
during the past year in which exophoria was pro-
duced or increased by over-correction of hyperme-
tropia and prisms base in had been added to the
glasses for the refraction, the total result to the
exophoria being an increase ; these cases had asthe-
nopic symptoms which were often relieved when the
convex lenses were made weaker and the prisms re-
moved. Analysis of the results in such cases show
them to be in part due to mental causes connected
with the difference in vision, in part to refractive
causes, and hence the effects of the difference in cor-
rection take on an exaggerated aspect if referred to
the muscles alone. In the case of a physician with a
little exophoria, who gave up medicine twenty years
ago because he found no glasses to relieve his asthe-
nopia, and who had been much better with the last
glasses ordered for him than any previous ones, the
first glasses (for he had saved them) turned out to be
convex cylinders .75 and .50 fitted under atropine;
A Clinical Study. 81
the others were given on the same principle, except
the last, which was a concave cylinder, opposite
axis; this patient has since been able to use his
eyes freely and comfortably with treatment for the
muscular error. In cases in which the effect is out
of all proportion to the cause it is safe to refer
something to the imagination of the patient.
Accommodative exophoria from glasses also occurs
in presbyopic cases, and although the principles in
connection with accommodative exophoria as first
laid down by Bonders for such cases cannot be
successfully attacked, if any man expects to satisfy
his presbyopic patients by any attention to detail in
their glasses he will find himself sadly disappointed,
if he is alive to the results. Many of these patients
demand one glass with which they can see at far and
near points, and may consider an oculist incompe-
tent or obstinate if he fail to satisfy what they con-
sider a reasonable request. Convergence power is
usually weak in presbyopes ; convex glasses increase
this weakness by their effect upon the accommoda-
tion, and are usually centred too broadly, adding
an adverse prismatic effect to the other difficulties.
If muscular asthenopia already exists from weak
convergence the glasses may be centred in for a near
reading distance, but if the object is to avoid asthe-
nopia from glasses it will be safer to centre them
for the far point at which they may be used, since
6
82 Heterophorias and Insufficiencies.
it is easier to exercise convergence than divergence,
for evident reasons. Thus suppose a glass of -|- 2.25
about 15 mm. in front of each cornea or 30 mm. in
front of the centre of rotation, with a base line of
60 mm. It would be safer to centre these glasses at
60 mm. - -^ mm. = 56 mm., i. e., for their far
point of 1 8" or 450 mm. instead of nearer, so as not to
increase the asthenopia caused by looking off through
them, of which there is usually so much complaint.
Glasses for near work may be centred by sighting,
in a similar manner to those for distant vision.
There is one point in addition to those which
have received attention elsewhere concerning bifocal
glasses, and that is that the principal complaint con-
cerning these glasses is of the distortion of objects
and diplopia at the upper part of the junction of
that portion of the glass used for distance and the
paster. While the formula for proper centring to
prevent this prismatic action depends upon the dis-
tance of the upper edge of the paster from the
geometrical centre of the whole glass, and is tedious
to work out mathematically, it is a comparatively
easy matter for the manufacturer to cut his paster
so as to neutralize prismatic action at its upper edge.
I have had no complaints and seen no bad results
due to the symmetrical prismatic action of glasses
of equal strength decentred upwards or down-
wards. It takes more knowledge than I possess to
A Clinical Study. 83
successfully meet the demands of anisometropes
who desire comfortable non-distorting bifocals.
There is no definite agreement regarding what
should be considered normal balance for the ocular
muscles at a near point, such as the reading dis-
tance. Among healthy young adults with good
muscular strength and no particular refractive error,
who do not unduly use their eyes, as soldiers,
orthophoria is the rule at near points up to 12" or
less. This is indeed the best condition, yet is
found only exceptionally among patients applying
for eye treatment, with whom exophoria is the rule ;
while exophoria at a near point may easily occur
simply from relaxation of convergence and accom-
modation, I regard exophoria of over 2. at 13" as a
sign of probable weak convergence, and feel sure
that eyes with more dynamical divergence than this
are usually more or less asthenopic from weak con-
vergence. In this I differ from some other observers,
who regard 4. or 5. of exophoria at reading distance
as having no significance.
Much has been said regarding the production of
heterophoria by glasses, but nothing much about
the cases in which the eyes are forced into equilib-
rium notwithstanding the adverse prismatic effect
of a decentred lens, on the principle which causes
normal muscles to readjust themselves to differences
in the height of the eyes. The following case is an
84 Heterophorias and Insufficiencies.
example of accommodative exophoria to which was
added an adverse prismatic action of over 6 D's from
decentred glasses, the whole error being rendered
latent by spasm of the weak interni. A young lady
with constant severe frontal headache, dizziness,
which had lasted for years, and chorea, was wearing
eye-glasses with 5.50 o.u. in such a manner that
a tight spring far forward on the nose brought the
p.d. (and o.c.) at 2", the base line being 2%" '. V.
O.U. = f$. There was weak convergence for near
points, but at 20 feet there was no appreciable
heterophoria, convergence 14., divergence 7. Sph.
6. at 2%" o.c. was ordered, and one month later
there was esophoria 3., convergence 12., divergence
8. at 20 feet. Orthophoria at 13" with convergence
30., divergence 14. The headache was no better
and I began to doubt my diagnosis of exophoria
and spasm of convergence from improperly centred
glasses, and favored choreic spasm, or accommoda-
tive spasm from concave glasses, more than I had at
first ; however I persisted, and one month after the
last examination exophoria of 2. with convergence
of 30. and divergence of 10. appeared and the condi-
tion of the eye muscles has changed but little
since; the headache became better at this time, and
each time it began to reappear the glasses were
ordered with o.c. 3 mm. farther out. The last order,
eighteen months after the first, was with the
A Clinical Study. 85
o.c. 24". Divergence was then 11. with an ex-
o o
ophoria of 3., and with the glasses 1.50 of exophoria
still remains; the headache has not returned during
the year and a half since then, and as choreic move-
ments of the head and neck have disappeared, or
greatly diminished, the correcting glass has not
been further disturbed, or other eye treatment in-
stituted in the vain hope of helping the general
nervous difficulty.
The above points taken from the written history
of this rather unusual case do not show the main
reason why a diagnosis of spasm of the interni from
misplaced glasses was made in the first instance,
and I add from a clear recollection upon that matter
that the orthophoria at the first test was shown
without the glasses, with the glasses at 2" o.c., or
at 2-f" o.c., with the same action upon accommoda-
tion, yet a variation of 6 D's of prismatic action.
A side issue in the case was the demonstration
of the fact that people cannot be expected to
wear the nose-piece of eye-glasses in a position to
which habit and the shape of the nose have not
previously accustomed them ; if a new position of
the glass is desired it must be obtained by variation
of the length and shape of the posts connecting the
nose-piece with the glasses.
Muscular Exophoria. Exophoria with insuffi-
ciency of the interni or of convergence will be
86 Heterophorias and Insufficiencies.
considered in the next chapter. Exophoria with
excess of divergence can be diagnosed by the
tests for the muscles at 20 feet. Divergence of
12. or more always constitutes excess, and from 9.
to ii. usually. Convergence commonly decreases as
age advances, and so soon as divergence excess with
asthenopia is known to be permanent there should
be a tenotomy of one externus, followed if neces-
sary by a tenotomy of the other. This should be
done on the principles already described, and in
marked cases of excess needs to be complete, and
not infrequently the attachments of the insertion
loosened, to produce orthophoria in the middle of
the field, with divergence of 7. or 8. A single
tenotomy of an externus carefully done upon a well-
developed muscle, care being taken to divide the
tendon at its insertion and not loosen the attach-
ments, will seldom give more than 5 D's of effect.
As a rule the effect at the time of operation dimin-
ishes but little, if any, at a later period, if the cut
muscle is put upon the stretch for a few days after
operation by forced convergence; the most effec-
tive method of accomplishing this is to have the
eyes converge for a near object, as the finger,
several times a day, and once a day have this done
while the eyes are armed with converging prisms ;
observations upon cases months or years after this
operation show in general no more increase of
A Clinical Study. 87
exophoria than usually occurs in the natural course of
exophoria without operation. As a result of this
operation, increase in the power of convergence is
usually more than the decrease of divergence.
There is less apt to be this increased conver-
gence in myopic eyes, and in those where the
muscles are poorly developed. In the following
case increase of convergence was less than decrease
of divergence, and it is the only one in which I
have seen this occur. A poorly developed school-
boy of thirteen years of age, with myopia of 1.75,
showed in December, 1896, exophoria 2., con-
vergence 9., divergence 9. Nine months later exo-
phoria 3., convergence 7., divergence 9. Tenotomy
of the left externus was done and orthophoria re-
sulted. Six weeks later there was exophoria 2.,
convergence 9., divergence 9. Three months later
tenotomy of the right externus, resulting a week
after in orthophoria, convergence 10., divergence 6. ;
one month later, exophoria .5, convergence 9., di-
vergence 8. This condition has continued since,
the severe headaches which the patient had after
studying having been better, but, as general treat-
ment including arsenic and strychnine has been
used, it is doubtful whether the operations can claim
any appreciable credit.
Another case of a similar character shows that so
little result as this cannot be foretold. This was
88 Heterophorias and Insufficiencies.
the case of a man of twenty-five with severe and
constant headache made worse by near work. He
was of the same neurotic, ill-developed type, had
compound myopic astigmatism, which had been
carefully corrected one year before I saw him in
April, 1898, and had exophoria 4., convergence 6.,
divergence 10. Tenotomy of the left externus gave
but temporary relief as orthophoria only lasted a
week; so one month after the first operation I
over-corrected the exophoria by tenotomy of the
right externus, attaining esophoria 2., convergence
14., divergence 3., changing to orthophoria with
convergence 16., divergence 7., in two months.
The proportions changed to 12. versus 8. nine
months after the second operation, when the patient
reported that he had only had a few slight head-
aches when he was tired and had overused his eyes.
In contrast to these let me give the most marked
case of increase of convergence I have seen, in eyes
with hypermetropic astigmatism of .50 in one eye
and .25 in the other. A young lady of twenty-four
years came to me in May, 1899, a f ter a season of
operations upon the ocular muscles done for the
purpose of relieving her of extreme headaches, dizzi-
ness and nausea. She was wearing sph. -j- I. with
prisms of 2.50 base in over each eye for reading;
exophoria of 5. at 13" being increased to 8. by this
combination. She had, at 20 feet, exophoria of
A Clinical Study. 89
I D. with the phorometer, 7. or more with the
Maddox rod; convergence 20., divergence 20. I
first tried correction of the slight astigmatism, and
removal of the objectionable glasses, but with little
relief, so three weeks later I divided the left exter-
nus; all the exophoria I could get after this by any
test was 4., and the first result and that five months
after varied only I., convergence going to 38., diver-
gence to 16. This improvement in the eyes and a
summer's vacation gave no relief to the symptoms,
although general tonic treatment had been kept up.
I then divided the right externus, and the patient be-
coming exhausted and faint from a rather prolonged
operation in her neurasthenic state, a free tenotomy
left 2. of exophoria, although divergence was but 6.
and homonymous diplopia was present on the right
side of the field. One week later, as convergence
improved, the result was esophoria 2., convergence
40., divergence 5. In one month, however, there
was orthophoria for far and near with a convergence
of 65., divergence 9., at 20 feet. The action of
the muscles was now co-ordinate, dizziness and nau-
sea had disappeared and the general headache with
them ; the distressing pain at the nape of the neck
had not yet entirely disappeared, although it did
soon after, the patient reporting herself well two
months later and showing the same muscular condi-
tion as that last given. In this case reduction of
90 Heterophorias and Insufficiencies.
divergence II D's gave increased convergence of
45. A contrast to this as regards result to the
symptoms before a good muscle test was obtained,
yet agreeing as regards improvement in converging
power, is shown by the case of a girl of nine years,
who had crossed diplopia under a red glass, and in
whom I did free tenotomy of the left externus, with
the result that two months later while convergence
for near work had improved, at 20 feet there was
convergence of 2. only, divergence of 20. Eight
months later there was convergence of 12., diver-
gence 14. Severe and frequent headaches had dis-
appeared since the operation. In these two cases
post-operative hyperphoria was temporarily pro-
duced and disappeared in a week ; a not very un-
common experience.
In contrast to these complete operations giving
slight results let me say that I have a few times pro-
duced convergent squint and homonymous diplopia
before an externus seemed to be completely divided,
and have usually advanced the cut muscle with good
result, by means of a single stitch tightened until
orthophoria in the centre of the field was produced.
In one case, however, the patient became hysterical
about the stitch and promised faithfully to let me
do anything 1 wished in the way of an operation
later if I would remove it. As I wished to watch
the effect, and the onus was on her, I left the muscle
A Clinical Study. 91
as it was by drawing out the stitch, which had not
yet been tied. There was, strangely enough, no
dizziness following the operation, the headache
which had not yielded to correction of the refrac-
tion, or other treatment, was relieved, and two
months later the diplopia could not be obtained at
the periphery of the field except by means of a red
glass. A test four months after this showed ortho-
phoria.
In case it should seem strange that readjustment
should follow in some cases too little, in others too
much operative effect, let me say that in the former
class the exercises above described for a near point
are used, while in the latter near work is prohibited
for a time, but the eyes are encouraged to fix dis-
tant objects. This small detail of treatment would
be of little use, except for the principle that people
with strong desire for binocular fixation tend to
force the eyes into orthophoria in the centre of the
field, as soon as the muscular condition will per-
mit of such a thing ; let me say, however, that the
above cases are for me the exception ; in most of the
others orthophoria was the primary result of the first
operation. In such a case, if the effect decreases
later, when a second operation is done I over-correct
by an amount equal to the decrease which occurred
after the first operation.
Exophoria of 4. or more with more than 12. of
92 Hetcrophorias and Insufficiencies.
divergence will usually require an apparently com-
plete tenotomy. By apparently, I mean that it is
difficult to cut across the tendon of a muscle with-
out loosening the subconjunctival tissue, or the at-
tachments of the muscle to the capsule of Tenon,
through a small opening in the conjunctiva, and be
sure of the complete character of the division, even
when the line of insertion to the sclera can be seen ;
a small band of fibres, deep and peripheral, may
easily escape notice. It should be remembered
that the object is to remove the muscular difficulty,
not to prove the division of a muscle. In weaker
muscles tenotomies which only partially divide the
tendon will produce results ; as these cases are often
of the neurasthenic type, I generally avoid operation
upon them and cannot speak so definitely of them as
of the class in which I find that division of the ten-
don nearly, or completely, in such a way as to avoid
too much retraction of the muscle, is necessary to
obtain a definite result.
It is by no means easy to tell in advance how
much a muscle will retract, hence the necessity of
graduating the operation by testing the eyes at inter-
vals. Every competent operator uses this principle
in cases of squint when he looks at the eyes to see
whether he has advancement or tenotomy enough to
reduce the deformity; in this case he is operating
for appearance, in the other for muscular balance.
A Clinical Study. 93
In exophoria cases it is well to take the desired
strength of divergence as a guide in operating as
well as the production of orthophoria.
It is very important to consider hyperphoria in its
bearing upon exophoria and esophoria. The lateral
deviations may improve or disappear when hyper-
phoria is corrected, or they may require further cor-
rection ; the method already described of correcting
the hyperphoria with prisms, then testing the lateral
balance with the rod, also trying the effect upon
convergence and divergence, gives valuable informa-
tion but is not infallible.
Neurasthenia as a result of operations upon the
eye muscles is not uncommon, from the nervous
anxiety and traumatism, and it is well for the opera-
tor to get through by means of as few operations as
possible. If the symptoms are no better after a
couple of operations, it is just as well to inquire and
determine whether a neurasthenic asthenopia is not
replacing a muscular asthenopia, and treat the case
accordingly.
CHAPTER V.
INSUFFICIENCY OF CONVERGENCE; NEURASTHENIC
MUSCULAR ASTHENOPIA; INEFFICIENCY OF
THE OCULAR MUSCLES.
IT has been a time-honored custom among oph-
thalmologists, to group all cases of asthenopia
of which they failed to understand the origin as
neurasthenic. In the United States a race of rest-
less adventurous explorers, fighters of Indians and
revolutionists, have, in the persons of their descend-
ants and successors, taken to city life, books, physi-
cal appliances, artistic paraphernalia, steam heat,
and other appurtenances of what they call education
and civilization, with the same result that obtains
when the country-bred boy settles down to sedentary
city life trouble with the digestion, circulation, and
nervous system. The first attempts at imitating
foreign civilization in this country resulted twenty-
five or more years ago in the thin, pale, nervous
young girl; as admiration for the civilization of
France began to be replaced by imitation of the
English style of life this type of woman began to
94
A Clinical Study. 95
be replaced by the larger, stronger, rosier type in
which forced development of the bones, muscles,
and circulation was expected to properly adjust the
balance in the forced brain and nervous system,
with the result that nervous irritability with some
energy and endurance began to give way to neuras-
thenia and emotional disturbances of the nervous
system. In the first type by means of tonics, nour-
ishing food, fresh air, and exercise we expect to
meet the indications ; if in the course of a generation
or two the second is the result of this method, what
next ?
The undoubted soundness of the view that atten-
tion to hygiene is the key to development of the
nervous system as well as the other forms of tissue
cannot be questioned ; yet the occurrence of weak-
ness in the ocular muscles with other undoubted
evidences of lack of force, in the well-nourished and
apparently well-developed American youth of to-
day, show that nervous degeneration cannot always
be successfully combated by a general knowledge
that nourishing food, fresh air, and exercise tend
to develop the human animal.
The main point to be insisted upon here is that a
neurasthenic patient with muscular asthenopia is
not of necessity a case of neurasthenic muscular
asthenopia. The more neurotic a person is the
more likely he or she is to suffer from nervous
96 Heterophorias and Insufficiencies.
symptoms referable to ocular defects, just as a case
of chronic gastric catarrh has more dizziness and
nausea from eye strain than one with better diges-
tion. Occasionally muscular and nervous signs of
exhaustion occur from excessive use of the eyes,
with hyperesthesia retinae and even displacement
fields of vision, in persons who have not shown evi-
dences of exhaustion in any other function than that
of vision ; as the exhaustion is mainly of nervous
tissue of the eyes and their cerebral connections,
these are properly to be considered as cases of neu-
rasthenic asthenopia, although general evidences of
nerve exhaustion are absent. Perhaps " neurasthe-
nopia " would be a proper term for them.
The type of muscular weakness which belongs
to the neurasthenic is that known as insufficiency of
convergence, or defective amplitude of convergence;
this latter term, with its positive and negative fac-
tors, is proper but formidable, and studies already
made under this head are of little clinical value as
regards diagnosis and treatment of heterophoria. I
here take the liberty of proposing the term " Ineffi-
ciency of the Ocular Muscles" for the class of cases
to be described ; inefficiency means lack of power, or
the desire for power, and exactly denotes the con-
dition of weak muscular action arising from lack of
development of muscles or of nervous tissue, fatigue
and lack of energy, or want of ambition, which
A Clinical Study. 97
characterizes neurasthenic muscular asthenopia.
We often meet in the American youth of to-day
and in others broken down by worry or illness, such
conditions of the ocular muscles as follows: Ortho-
phoria or esophoria i. to 2., convergence 9. to 12.,
divergence 3., 4., or 5. ; orthophoria or exophoria, I.
or 2., convergence from 6. to 8., divergence from 8. to
6. Fixation for a near point is weak and inadequate,
with exophoria at 13" from a few dioptrics up to
actual divergence of the lines of fixation. Sursum-
duction usually I. or 1.50. This condition may be
acquired, and if due to temporary general or ocular
fatigue consist merely of a relative insufficiency of
convergence, with little or no weakness or excess
of divergence, and yield rather easily to ocular rest
and general treatment with strychnine. More often
the condition is permanent, both the ocular mus-
cles and the brain centres being undeveloped, and
I regard this condition as shown by inefficiency
of the ocular muscles as one of the stigmata of
degeneration.
Occasionally the apparent lack of muscular power
is simply a sign of constitutional laziness and in
such cases will not cause pain and discomfort ;
sometimes there is a hysterical element, more or
less latent, and the muscular strength is variable.
Variation in the power of convergence and diver-
gence, except in cases of hyperphoria, or functional
98 Heterophorias and Insufficiencies.
or organic nervous disease, does not seem to occur
to any extent in my cases of late years, perhaps
because the routine tests are made over and over
under the same conditions as regards the manner of
testing, and with precautions against variation.
In neurasthenic subjects the weak ocular muscles,
sensitive retinae, irritable reflex centres, and gener-
ally inefficient muscular and nervous force cause
undue susceptibility to slight physical variations
affecting the eyes, while the cerebral condition is
often such that general effects from slight local
causes may be exaggerated, distorted, or imagined ;
in treating such cases, although the underlying
principles are the same as in others, the point of
view should change so materially that they must of
necessity be considered as a separate class. For
them the use of tinted glasses should be discour-
aged ; the chemical rays of light, the most if not the
only injurious ones to the eyes, do not penetrate
glass to any extent, irradiation of light increases
with refractive error, and hence correcting glasses
are indicated if the patient's prejudices and nervous
condition will permit glasses to be worn. Strong
glasses may not be borne, even if they barely correct
manifest error, and care must be taken to guard
against strong or adverse prismatic effects. In a
few cases in which operations seemed indicated to
me I found the muscles ill developed, as might be
A Clinical Study. 99
supposed from the nature of the cases and the re-
sults of tests for muscular power; such muscles may
be badly injured by tenotomy and cannot be much
strengthened by advancement. If lack of nervous
impulse is the cause of the inefficiency, or it is due
to temporary exhaustion of muscular or nervous
force where the muscles are well developed, opera-
tions are surely not indicated. Since operations are
of little or no use for the inefficiency, and may be
harmful to the neurasthenia, they could only apply
to the correction of slight heterophorias when such
are present and cannot be successfully treated in
some other manner; they would, therefore, be pref-
erably postponed until general treatment has failed
to relieve the asthenopia, and the general strength
of the ocular muscles has reached a maximum.
It must be kept in mind that one form of insuffi-
ciency yet remained to be considered when we
reached this chapter, insufficiency of the interni, or
convergence, without excess of divergence, not ac-
companying hyperphoria, nor accommodative, and
that this condition is neurasthenic and constitutes
inefficiency of the ocular muscles. Although, as in
the first case cited under the heading exophoria, it
may be seen that advancement of the interni appears
to be indicated, this operation at the best may
cause too much post-operative annoyance to be ap-
propriate to the neurasthenic condition, and we may
ioo Hcterophorias and Insufficiencies.
be compelled to confine ourselves, when an opera-
tion is justifiable, to cutting some fibres of a superior
or external rectus for the correction of hyperphoria
or exophoria, which would be more formidable ex-
cept that in cases of inefficiency the operation is a
slight one, complete division of the tendon seldom
being necessary.
Extensive discussion of general treatment is be-
yond the province of this work. Strychnine is the
general remedy most applicable to strengthen mus-
cular and reflex action. It is given at first in small
doses, then the dose is increased from time to time.
It seems to me that in this manner we find just the
dose that may be borne by a patient, not that we
induce toleration for the drug. The remedy bene-
fits some cases quickly, others slowly, others not at
all; cases of orthophoria with insufficiency of con-
vergence, due to fatigue from excessive eye work,
do best with it, as previously stated ; cases of
esophoria with general nervous irritability do much
less well. Certain general conditions are a contra-
indication for strychnine, noticeably arteriosclerosis
with high arterial tension.
Decision regarding the comparative merits and
proper amount and character of rest and exercise in
the general treatment of these cases requires much
experience and nicety of judgment. It seems evi-
dent, however, that rest from that which fatigues or
A Clinical Study. 101
irritates the nervous system, or rest to an overused
structure or organ, would be, of necessity, indicated.
It is hard for some of us to see any rational treat-
ment for the eye with structural or functional weak-
ness, suffering from symptoms brought on by strain
of the weak part from overuse, not founded upon
rest for the weary organ. Neuralgias in general are
treated by attempts to improve the health and give
rest to the painful part. Since the eyes are con-
stantly in use when the lids are open, we are unable
to obtain absolute rest without imperiling the gen-
eral health ; so we partially rest the ciliary muscle
and meet visual and retinal indications by correcting
the refraction, and attempt to give rest to the weak
muscles by means of prisms, while we try to obtain
a proper muscular balance by various methods. It
is not the insufficiency which causes asthenopia but
use of the insufficient muscles; insufficiency of the
externi gives rise to headache with the most certainty
when the eyes are used to look at outside objects
from the windows of a moving train, while if no in-
sufficiency exists for a near point the eyes may be
used for reading, upon the same journey, without
discomfort; reading from a prone position causes
trouble especially, or solely, in cases of hyperphoria.
In inefficiency the converging power suffers most;
the condition precedes the asthenopia, apparently,
as the weakness is congenital, or acquired from
IO2 Heterophorias and Insufficiencies.
worry, illness, or the wear and tear of surgical in-
juries or operations, in the latter cases the asthe-
nopia and headache beginning after hard use of the
eyes for reading, or other near work, during conva-
lescence. Headache, dizziness, nausea, conjunctival
congestion, and pain at the back of the neck are
most in evidence with convergence.
Should it appear that we are indulging in an un-
necessary amount of detail in order to show that
rest is so important in the treatment of exhausted
ocular muscles, it must be remembered that there
was a time, perhaps forgotten by a younger genera-
tion, when a well-known American ophthalmologist
instituted a treatment for asthenopia consisting of
ocular gymnastics (and ointments for the forehead),
which was received by some with great enthusiasm
and expected by them to relieve all forms of eye
strain not evidently accommodative ; also, that forms
of exercise for the ocular muscles are still in use with
many statements on record regarding the increased
strength obtained, as shown by tests and relief to
symptoms. The first claim has been considered in
an early portion of this work; as to the second,
neurasthenia is essentially a chronic condition with
intermittent symptoms, and statements regarding
relief to symptoms are to be received with caution ;
they may, in fact, be a measure of the self-satisfac-
tion of the man presenting them, or an expression
A Clinical Study. 103
of an evident appreciation of his efforts by his
patients, rather than an actual count of tangible re-
sults which is well-nigh impossible to make in cases
with subjective symptoms.
The general rule should be that eyes are not to
be used for near work after they show the slightest
signs of fatigue. When, as in my cases, tests for
convergence bear a definite relation to the ability
for near work, they may be used as a guide. Thus,
with prism convergence of 8 D's for distance, the
eyes are to be used at first not over five minutes
twice a day, this time to be increased with increased
convergence power, until with 16 D's the eyes are
used for near work half an hour four times a day.
We have already noted the effect of emotion
upon the ocular muscles, and incidentally it has been
suggested that those emotions which cause excite-
ment or irritability induce spasm of strong muscles,
while those which cause exhaustion increase insuffi-
ciency ; in this way latent heterophoria may become
manifest, or pseudo-heterophoria may be produced.
Nervous young women sometimes dread an examina-
tion of the eyes, and having a little asthenopia, are
fearful that this signifies some dread disease. Fear
not only dilates the pupil, but relaxes accommoda-
tion and convergence. This condition being limited
in duration, certain cases which show inefficiency
of the ocular muscles at a first test will show
104 Heterophorias and Insufficiencies.
improvement of convergence at a later period, with-
out regard to treatment. The contradictory in-
dications to be met in treating the asthenopia and
convincing the patient that there is nothing the
matter with the eyes, may sometimes require mental
more than direct medical treatment.
When glasses are worn, especially convex ones, a
new relation is set up between accommodation and
convergence, and muscular asthenopia may result,
the condition being more intractable as age ad-
vances, and most complained of by neurasthenic
patients. To overcome the difficulty it is absolutely
necessary that the eyes should converge with the
glasses, and if a neurotic patient insists upon the
impossibility of using the eyes for near work, con-
verging exercises with the finger or with prisms may
possibly be indicated. These cases may be diag-
nosed by the increase of heterophoria with glasses at
a near point, when the centres are in the lines of
fixation for that point.
The division of asthenopia into retinal, from gen-
eral disease, accommodative, from errors of refraction,
and muscular is not sufficiently comprehensive. It
does not include the effect of certain materials upon
the eyes, as, for example, glazed paper ; operatives
who make white boxes with this material suffer from
eye strain which ceases with a change of occupa-
tion. Other causes of asthenopia, such as a bent
A Clinical Study. 105
position of the head, use of the eyes immediately
after meals, poor position and character of the
illumination used, are also not included in the above
classification. We all know that somewhat modified
daylight from above and to the left and rear is de-
sirable, but the character of the artificial illumina-
tion which is least injurious to the eyes is still in
doubt. A belief in the bad effects of insufficient
illumination is well-nigh universal; that poor light
causes ocular discomfort is perfectly evident, yet it
is difficult to see how it could do the harm, func-
tionally or organically, that must come from excess
of illumination. In the medium limits of illumina-
tion, where increased light causes increase of vision,
the latter increases only about as the logarithm of
the former, and the excess of light is injurious to the
retina. If we look at the history of any nation, or the
comparative history of all, we see without exception
that asthenopia increases directly with the increase
in amount and intensity of artificial illumination.
Here we have the combination of causes which pro-
duce " neurasthenopia " or ocular exhaustion, with-
out regard to the nature of the defects existing in
the structure or dynamics of the eyes: the artificial
life which goes with artificial illumination, the ability
to continue using the eyes when they are fatigued
and should be rested, and the direct chemical effect
of improper light upon the exhausted retina.
106 Heterophorias and Insufficiencies.
It may seem that these and some other considera-
tions herein presented have little, if any, direct
bearing upon the ocular muscles. This book is not
intended for those who can treat asthenopia success-
fully by ignoring the ocular muscles, or those who
can obtain the same happy result through these
muscles alone.
118 EAST 720 STREET, NEW YORK,
March 5, 1900.
THE LIBRj
UNIVERSITY OF CALIFORNIA
LOS ANGELES
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