CULAR 
 MECHANISM OF THE EYES 
 
 AND 
 
 ROUTINE IN EYE WORK 
 
 SAVAGE 
 
/ BERKELEY 
 
 RY 
 
 I Of 
 
THE NERVO-MUSCULAR 
 MECHANISM OF THE EYES 
 
 AND 
 
 ROUTINE IN EYE WORK 
 
 BY 
 
 G. C. SAVAGE, M.D. 
 
 Author of New Truths in Ophthalmology (1S93); of Ophthal 
 
 mic Myology (1902-11); of Ophthalmic Neuro-Myology 
 
 (1905); Ex-President of the Nashville Academy of 
 
 Medicine; Ex-President of the Tennessee State 
 
 Medical Association; Ex-President of the 
 
 Southern Medical Association; Ex-Chah- 
 
 man of Section of Ophthalmology of 
 
 American Medical Association. 
 
 Three full-page plates and four cuts 
 
 Published by the Author, Nashville, Tenn. 
 Printed by McQuiddy Printing Company, Nashville, Tenn. 
 
OPTOMETRY LIBRARY 
 
 Copyright, 1916 
 By G. C. Savage. M.D. 
 
PREFACE 
 
 This little book is published with the hope that 
 its contents will create, in the minds of many 
 readers, a desire to take up, with the view of 
 mastering, the whole study of the ocular mus- 
 cles ; also with the view of intensifying, in other 
 readers, such a desire as may have been pre- 
 viously created, but allowed to remain unsatis- 
 fied, because, forsooth, some one, supposed to be 
 a leader in everything worth while, had said that 
 " the muscle study is a myth, or at most is not 
 worth serious consideration." In all the domain 
 of Ophthalmology there is no other subject of 
 equal importance with that of Ophthalmic My- 
 ology, and yet it is a study easily mastered, when 
 mastery is earnestly sought, both from the sci- 
 entific viewpoint and that of practicality. Any 
 neglect of this study is hurtful to the patient and 
 harmful to the practitioner. In his books and 
 papers the aim of the author has always been to 
 make clear and easy the study of the ocular mus- 
 cles from the only two points of view — the mus- 
 cles themselves and the brain centers controlling 
 them in their individual and associated actions. 
 
BERKELEY 
 
 RY 
 
 UNIVERSITY OP 
 
 CALIFORNIA 
 
THE NERVO-MUSCULAR MECHAN- 
 ISM OF THE EYES* 
 
 In the study of the motility of the eyes, 
 there are fundamentals that must be 
 known and appreciated in order that the 
 subject may be clearly understood. These 
 fundamentals may be briefly stated as fol- 
 lows : 
 
 1. The image of the object on which 
 the 'vision is to be fixed must lie on the 
 macula. 
 
 2. The lines connecting this image and 
 its object must be straight lines passing 
 through the center of the retinal concave. 
 
 3. Every other object in the visual field 
 and its image must, likewise, be connected 
 by straight lines passing through the center of 
 the retinal concave. 
 
 4. All visual lines, whether direct or in- 
 direct, are radii of the retinal curvature 
 prolonged, and hence each visual line must 
 cross all other visual lines at the center of 
 the retinal concave. 
 
 5. Any two objects in viewable space 
 bear the same relationship, in degrees, 
 as do their retinal images. 
 
 6. The direct or primary line of vision 
 
 •Read in Eye, Ear, Nose and Throat Section. Southern 
 Medical Association, Ninth Annual Meeting. Dallas. Tex., 
 Nov. 8-11, 1915. Reprint from the Southern Medical Jour- 
 nal, Birmingham, Ala. 
 
6 The Nervo-Muscular Mechanism of the Eyes 
 
 is the visual axis which starts from the 
 central point of the macula, while all other 
 visual lines are indirect or secondary. 
 
 7. Any secondary point in space may 
 become the point of direct view by a shift- 
 ing of the visual axis into the position of 
 the secondary visual line which connected 
 that point with its image before the rota- 
 tion began, which is possible only because 
 the rotation is around that point through 
 which all visual lines pass, the center of 
 the retinal concave, which is the center of 
 rotation. 
 
 Only on the conceptions stated above 
 can be formulated the true mental law of 
 visible direction : "All lines of direction 
 are radii of retinal curvature prolonged.'' 
 In the light of this law all ocular ro- 
 tations can be understood; but, before 
 studying these rotations and the means by 
 which they are accomplished, some essen- 
 tial physical properties of the globe must 
 be set forth. The poles of the eye must be 
 correctly located ; the -meridians must be 
 properly constructed; and the equator 
 must be fitly related to the poles. The 
 fatal mistake of Helmholtz, in his chapter 
 on "Movements of the Eyes," was in his 
 not making the central point of the macula 
 always the posterior pole of the eye. He 
 fell into this error because he chose, as 
 the location of the anterior pole of the 
 
The Nervo-Muscular Mechanism of the Eyes 7 
 
 eye, the center of the corneal curve. His 
 optic axis he constructed by carrying a 
 line from his supposed anterior pole back 
 through the center of rotation to the ret- 
 ina, and named the retinal end of that 
 line the posterior pole. Confessing, as he 
 did, that in ideal eyes the posterior pole 
 and the central point of the macula were 
 one and the same, he gave himself the 
 opportunity to rid himself of his error in 
 locating the poles. That he did not do 
 this is explainable only on the ground of 
 his false conception of the law of visible 
 direction which may be expressed in these 
 words: "All lines of direction are axial 
 rays of light and cross each other at the 
 nodal point." His conception of the law 
 of visible direction and his location of the 
 poles of the eye made his location of the 
 equator incorrect and his construction of 
 the corneo-retinal meridians wrong. 
 
 With the center of the macula as the 
 posterior pole of all eyes, the anterior pole 
 may, or may not, be the center of the cor- 
 nea. . It is the center of the cornea only 
 in ideal eyes. Through the true posterior 
 pole of the eye all retinal meridians pass. 
 Therefore, the center of the macula is 
 common to all the retinal meridians. The 
 only other point through which these me- 
 ridians can pass is the anterior pole,— -the 
 second common point for all meridians. 
 
8 The Nervo-Muscular Mechanism of the lives 
 
 The only line common to the planes of all 
 the meridians is the line connecting the 
 two poles, the visual axis which, in all 
 eyes, is the true optic axis. 
 
 The equator of the eye is that circle 
 which passes around the eye, equally dis- 
 tant, everywhere, from the two poles. Its 
 plane cuts the center of rotation and is at 
 right angles to the planes of all the me- 
 ridians. In the plane of the equator there 
 lie as many diameters as there are me- 
 ridional planes; but only two of these de- 
 mand any study. These two diameters lie, 
 respectively, in the planes of the vertical 
 and horizontal meridians, as well as in 
 the plane of the equator. It is around 
 one or both of these diameters, as axes, 
 that all possible ocular rotations must 
 take place. The line to be guided by the 
 muscles and nerves of the eye, in any ro- 
 tation, is common to the planes of both 
 the vertical and horizontal meridians, 
 which has already been shown to be the 
 visual axis, — the true optic axis, — around 
 which rotations are denied, except in nat- 
 ural or artificial oblique astigmatism. 
 
 In space, just as in the eye, there are 
 points and lines, both straight and curved, 
 to be known in order to arrive at a cor- 
 rect understanding of ocular rotations. 
 One of these lines is the visual axis ex- 
 tended, on which must lie any object to be 
 
The Nervo-Muscular Mechanism of the Eyes 9 
 
 looked at fixedly. The location of such an 
 object or point is the spacial pole of the 
 eye. While the anterior and posterior 
 poles of the eye have a fixed distance be- 
 tween them and can not vary their dis- 
 tance from the center of rotation, the spa- 
 cial pole may be at any distance from the 
 two ocular poles and from the center of 
 rotation. Through the spacial pole of an 
 eye pass spacial meridians, which are 
 great circles concentric with the retinal 
 meridians. The planes of the vertical and 
 horizontal retinal meridians prolonged 
 into space become the planes of the verti- 
 cal and horizontal spacial meridians. The 
 planes of all oblique retinal meridians bear 
 a like relationship to the oblique spacial 
 meridians. No point can be in viewable 
 space which does not lie on some spacial 
 meridian, and the eye is so constructed, 
 as to its refractive power, as to compel 
 the image of that point to fall on the reti- 
 nal meridian having a common plane with 
 the spacial meridian. Such a point in 
 space, if secondary, is just as far removed, 
 in degrees, from the spacial pole as its 
 image is removed from the central point 
 • of the macula. The line connecting the 
 secondary point and its image forms its 
 two angles with the visual axis at the cen- 
 ter of rotation, which angles are equal be- 
 cause opposite. 
 
10 The Ncn'o-Muscular Mechanism of the Eyes 
 
 The spacial equator is in the plane of 
 the equator of the eye, but the former va- 
 ries in size, always corresponding with 
 the spacial meridians both as to size and 
 as to its distance from the center of rota- 
 tion. Any number of small spacial cir- 
 cles may be constructed parallel with the 
 spacial equator and between it and the 
 spacial pole, their diameters growing 
 shorter and shorter as they proceed from 
 the equator toward the pole, reaching zero 
 at the pole. For convenience of study, 
 these spacial parallels may be placed 10° 
 apart, the point of starting being the spa- 
 cial pole. Likewise retinal parallels might 
 be constructed 10° apart, the smaller one 
 being 10° from the posterior pole of the 
 eye. Since the spacial meridians corre- 
 spond with their respective retinal me- 
 ridians, point with point everywhere, a 
 spacial parallel at a given distance from 
 the spacial pole must correspond every- 
 where with a retinal parallel located the 
 same number of degrees from the poste- 
 rior pole of the eye. 
 
 With the foregoing facts fixed in the, 
 mind, , monocular rotations ought not to 
 be difficult to understand. In monocular 
 rotation every rotation plane is a merid- 
 ional plane extended, and in the spacial 
 part of this plane lie both the first and 
 second points of view, while, in its retinal 
 
The Nervo-Muscular Mechanism of the Eyes 11 
 
 part, lie the images of the two points. 
 The first point of view must be at the 
 spacial pole and its image must be on the 
 central point of the macula; the second 
 point of view must be just as many de- 
 grees from the spacial pole, on a given 
 spacial meridian, as its image is removed 
 from the retinal pole, on the correspond- 
 ing retinal meridian. The change from 
 the one point of view to the other is but 
 a shifting of the visual axis in the plane 
 common to the following five points: the 
 first and second points of view, their two 
 retinal images, and the center of rotation. 
 In the shifting the spacial end of the vis- 
 ual axis moves from the primary to the 
 secondary point, while the retinal end 
 moves from the primary to the secondary 
 image, the motion being around the cen- 
 tral point of the retinal concave, which 
 is also the central point of the spacial con- 
 cave. 
 
 Every pair of eyes, endowed with the 
 possibility of binocular single vision, can 
 be made to fuse their respective spacial 
 fields into a single binocular spacial field, 
 with a binocular pole, meridians and par- 
 allels. The fundamental fact of binocu- 
 lar single vision is common brain cell con- 
 nection; that is, each visual cell is diax- 
 onic, one axone going to a point in one 
 retina,while the other axone goes to a 
 
12 The Nervo-Muscular Mechanism of the Eyes 
 
 point in the other retina; and thus is cre- 
 ated corresponding retinal points. With- 
 out such common brain cell connection, 
 the binocular spacial pole, meridians and 
 parallels would be impossible, for there 
 could be no corresponding retinal points. 
 This condition is not uncommon, and over 
 such eyes the law of binocular rotations 
 has no power. 
 
 Ocular rotations, whether monocular or 
 binocular, can not be understood except in 
 the light of the two planes of reference 
 shown in Fig. 4 on page 18. These two 
 planes are the fixed vertical and hori- 
 zontal planes of the head, the one, g-h-i-j, 
 being half-way between the centers of the 
 two eyes, the other, a-b-c-d, cutting the 
 centers of the two eyes. As their names 
 imply, these two planes are at right an- 
 gles to each other. The other plane, 
 k-l-m-n, shown in Fig. 4, is Listing's plane, 
 which is neither a plane of reference nor 
 is it a plane containing the axes of rota- 
 tions, as was once taught. The line e-f 
 is made by the intersection of the two 
 planes of reference. From the point / may 
 be studied the four cardinal directions, c 
 and d, directly to the left and right, in 
 the horizontal plane ; and i and j, directly 
 above and below, in the vertical plane. 
 Points not in one or the other of these 
 planes are obliquely related to the line of 
 
The Nervo-Muscular Mechanism of the Eyes 13 
 
 their intersection. The shifting of the 
 visual axes in either one of these planes 
 is the result of a cardinal rotation; when 
 the visual axes are made to movo out of 
 these planes, the rotation is oblique. Fig. 
 1 on page 15 represents a horizontal car- 
 dinal rotation; Fig. 2 represents a verti- 
 cal cardinal rotation; while Fig. 3 repre- 
 sents an oblique rotation. To these figures ref- 
 erence will again be made after a study of the 
 ocular muscles and the nerve centers controll- 
 ing them. 
 
 The ocular muscles, as to their origin, 
 course and insertion, or attachment to the 
 eye, are too well known to require study 
 here. The six muscles of each eye are di- 
 visible into three pairs as follows: (1) the 
 externus and the internus; (2) the supe- 
 rior and the inferior recti; and (3) the 
 superior and inferior obliques. If there 
 were but one eye, the posing of the head 
 would make it unimportant td study the 
 first and second grouping; but the third 
 grouping, even then, should not be ig- 
 nored, for the reason that no posing of 
 the head would greatly help them, if un- 
 balanced in tonicity, in their work of al- 
 ways keeping the vertical axis of the eye 
 parallel with the median plane of the 
 head. 
 
 In this grouping the two muscles of a 
 pair are related to each other as to tonic- 
 
14 The Nervo-Museular Mechanism of the Eyes 
 
 ity and not as to contractility. Hence 
 each pair should be studied when neither 
 muscle is under the active control of any 
 brain center. Such study is impossible, 
 if there is but one eye. Fortunately it is 
 a matter of no consequence, when there 
 is but one eye, . whether the first or the 
 second pair are equal or unequal in toni- 
 city. In binocular vision it is of im- 
 mense importance to know if the two mus- 
 cles of any one of the three pairs are of 
 equal or unequal tonicity; that is, are they 
 orthophoric or heterophoric? This, as to 
 the recti, best can be answered only when 
 the two eyes are dissociated in action by 
 ciated by means of the cyclophorometer. 
 means of the monocular phorometer; and 
 as to the obliques, when they are disso- 
 The oculist who neglects such a study of 
 the ocular muscles is unjust to himself and 
 cruel to his patients. 
 
 Great as is the temptation to enter here 
 into a full study of this feature of muscle 
 problems, I must not yield, as time will 
 not allow. I have heard otherwise well- 
 informed men boast of their ignorance of 
 heterophoric conditions; but that boast 
 would not now be a badge of respectabil- 
 ity. 
 
 In our study of Charts 1, 2, and 3 we will 
 see the wonderful provision in the brain for the 
 helpfulness of eyes, in the work of binoc- 
 
The Nervo-Muscular Mechanism of the Eyes 15 
 
 ular single vision, whose muscles, in one 
 
 or all of the three pairs, are heterophoric. 
 
 In the next grouping of the ocular mus- 
 
 Fig. I. 
 
 cles in pairs, the one muscle of every pair 
 will belong to one eye while the other mus- 
 cle of the pair will belong to the other 
 
16 The Nervo-Muscular Mechanism of the Eyes 
 
 eye. In this grouping the muscles will 
 be studied in action and not in a state of 
 rest. There are nine pairs: (1) the two 
 
 Fig. II. 
 
 superior recti for rotating the two eyes 
 directly upward; (2) the two inferior 
 recti for rotating the two eyes directly 
 
The Nervo-Muscular Mechanism of the Eyes 17 
 
 downward (these two rotations will be 
 around the horizontal axis of the eye, but 
 with torsion which must be prevented by- 
 
 Fig, in. 
 
 associated action of two pairs of the ob- 
 liques) ; (3) the two interni for converg- 
 ing the eyes on an object near bv (with- 
 
 2 
 
18 The Nervo-Muscular Mechanism of the Eyes 
 
 out torsion if the near point be in the ex- 
 tended horizontal plane of the head) ; (4) 
 the right externus and the left internus, 
 for effecting the right cardinal rotation; 
 (5) the left externus and the right inter- 
 nus, for effecting the left cardinal rota- 
 
 Fig. IV. 
 
 tion (these two rotations will be around 
 the vertical axis of the eye without tor- 
 sion) ; (6) the two superior obliques for 
 aiding the two inferior recti in the down- 
 ward cardinal rotation, their chief work 
 being to maintain the parallelism of the 
 two vertical axes with the median plane of 
 the head; (7) the two inferior obliques to 
 aid the two superior recti in the upward 
 cardinal rotation, their chief work being 
 
n 
 
oj r- or © © — 
 
 U 
 
 a 
 
 u 
 
o 
 
 OJ 
 
22 The Nervo-Muscular Mechanism of the Eyes 
 
 to prevent the loss of parallelism between 
 the vertical axes of the eyes and the me- 
 dian plane of the head; (8) the superior 
 oblique of the right eye and the inferior 
 oblique of the left eye to maintain paral- 
 lelism of the vertical axes of the eyes 
 with the median plane of the head, in 
 every rotation obliquely up and to the 
 right or down and to the left; (9) the su- 
 perior oblique of the left eye and the in- 
 ferior oblique of the right eye to prevent 
 loss of parallelism of the vertical axes of 
 the eyes with the median plane of the 
 head, in every rotation of the eyes ob- 
 liquely up and to the left or down and to 
 the right. Of these nine pairs, five are 
 of recti muscles and four are of oblique 
 muscles. 
 
 In the grouping of the ocular muscles 
 into active pairs, as above, each pair is 
 under the volitional control of one conju- 
 gate center. These centers, nine in all, 
 can be studied in Charts 1 and 2 in connection 
 with any one of the several plates, but 
 preferably in connection with that plate 
 not numbered. In orthophoric eyes no 
 other brain centers are needed in the four 
 cardinal rotations and in convergence. In 
 every oblique rotation of orthophoric eyes 
 other centers are needed in the interest 
 of binocular single vision. These centers 
 are necessary for all heterophoric eyes, 
 
The Nervo-Muscular Mechanism of the Eyes 23 
 
 whether at rest or in motion. These cen- 
 ters are at the base of the brain, and each 
 is connected with only a single muscle. 
 They are, therefore, twelve in number, six 
 being- on each side of the brain. The fu- 
 sion faculty of the mind — not volition — 
 presides over these centers and they are 
 made to serve in the interest of binocular 
 single vision and correct orientation. 
 
 Cardinal rotations of orthophoric eyes 
 are easier than oblique rotations, for the 
 reason that basal or fusion centers have 
 nothing to do in the former, while two 
 of these centers are necessarily in action 
 in every oblique rotation. In hetero- 
 phoric conditions, two or more of the basal 
 centers are constantly in a state of activ- 
 ity, whether the eyes be in rotation or at 
 rest — unacted on by any conjugate center. 
 The brain centers that are chargeable 
 with the "wear-and-tear" of eye strain are 
 the basal or fusion centers. The conju- 
 gate or volitional brain centers neither 
 cause heterophoric conditions nor do they 
 attempt to correct them. 
 
 All the brain centers controlling the oc- 
 ular muscles belong to one of two groups : 
 First, the cortical centers, which are un- 
 der the control of volition. The cells of 
 all these centers are diaxonic, one axone 
 going to one muscle of a pair, while the 
 other axone goes to the other muscle of 
 
24 The Nervo-Musculor Mechanism of the Eyes 
 
 that pair. The second group consists of 
 centers located at the base of the brain, 
 all the cells of which are monaxonic, each 
 center having under its control only one 
 muscle. These centers are all presided 
 over by the fusion faculty of the mind. 
 
 The cortical centers are properly called 
 conjugate centers, since each directs the 
 rotation of the two eyes. They are also 
 called verting centers, since it is neuricity 
 from one or other, or at most three, of 
 these, that causes the turning of the two 
 eyes from one point of view to another. 
 Since the point of view is changed only as 
 one wills to do so, another appropriate 
 name is volitional centers. 
 
 These centers can best be studied in the plates 
 collected in Charts 1 and 2, in which they are 
 shown schematically. Take the uncomplicated 
 plate, unnumbered, in Chart 2, for this purpose. 
 Eleven cortical centers are shown on each 
 side of the brain. The centers 10 and 11 
 do not belong to the extrinsic ocular mus- 
 cles, but to the sphincters of the iris and 
 the ciliary muscles. That leaves nine cen- 
 ters for the recti and the obliques. This 
 number corresponds precisely with the 
 number of pairs into which we have found 
 the muscles of the two eyes grouped. 
 There is, therefore, one conjugate center 
 for each pair. These centers and their 
 respective pairs of muscles are numbered 
 
The Nervo-Muscular Mechanism of the Eyes 25 
 
 in harmony in order to make their study 
 most easy. 
 
 A glance at the unnumbered plate will 
 show eighteen conjugate centers, nine of 
 which are represented by large circles, 
 while the remaining nine are represented 
 by small circles. Eight of the nine large 
 circles (1 to 9, except 5), in this and in 
 all the plates in charts are in the left side 
 of the brain, while the remaining large 
 circle (5) stands alone in the right side 
 of the brain. The large circles represent 
 the active conjugate centers in control of 
 the nine pairs of extrinsic ocular muscles. 
 The other small circles, eight of which (1 
 to 9, except 5), are in the right brain, 
 while the other one (5) is in the left 
 brain, represent the conjugate centers that 
 would have controlled the nine pairs of 
 the extrinsic ocular muscles, if the cause 
 determining which group of nine centers 
 should be active, had been in their favor. 
 
 At birth every one of the eighteen con- 
 jugate centers (1 to 9 on each side) stands 
 equally ready for action, and the diaxones 
 of all the cells of all these centers enter 
 into the formation of the three pairs 
 (third, fourth and sixth) of motor nerves, 
 by means of which the muscles are con- 
 nected with their respective centers. One- 
 half of these axones are to be forever in- 
 active, as if dead wires, for the nine cen- 
 
26 The Nervo-Muscular Mechanism of the Eyes 
 
 ters from which they go will never become 
 generators and dischargers of neuricity. 
 
 The cause that determines which nine 
 conjugate centers shall have control of the 
 extrinsic ocular muscles (also determin- 
 ing whether the right or left tenth and 
 eleventh conjugate centers shall control 
 the ciliary muscles and the pupil contract- 
 ors) is anatomic. If the diaxonic visual 
 cells connected with the two maculas are 
 located in the left cuneus, all the active 
 conjugate centers, except the fifth, will 
 be in the left brain, as shown in all the 
 plates of Charts 1 and 2. The same condition 
 also predetermines the location of the ac- 
 tive speech center in the left brain. Such 
 a person is predestined to be right-hand- 
 ed; and the higher faculties of his mind 
 will use only the left side of the brain. 
 The reverse of all this would be true if the 
 diaxonic visual cells connected with the 
 two maculas were located in the right 
 cuneus. In such a person the only active 
 conjugate center in the left brain would 
 be the fourth. The left fourth and the 
 right fifth conjugate centers are always 
 active, whether the person be right- or 
 left-handed. 
 
 The fusion centers, twelve in number, 
 one for each ocular muscle, exist in the 
 interest of binocular single vision. All 
 these are ready for action at birth, and 
 
The N ervo -Muscular Mechanism of the Eyes 27 
 
 each one always remains ready to store 
 and discharge neuricity to the muscle to 
 which it belongs when that muscle must 
 contract in order that diplopia may be 
 prevented, and orientation may be correct. 
 In orthophoric eyes oblique rotations could 
 not be accomplished, and single vision be 
 maintained, without the aid of two of the 
 twelve fusion centers. In heterophoric 
 eyes there would be diplopia whether the 
 eyes were at rest or in motion, were it not 
 for these fusion centers. The nature of 
 the imbalance determines which of these 
 centers shall be in constant action — in 
 esophoria, the right and left fourth; in 
 exophoria, the right and left third ; in left 
 hyperphoria and right cataphoria, the 
 right first and the left second, and so' on. 
 Imbalance of each of the three pairs of 
 muscles would keep in constant activity 
 six of the twelve basal centers. Untreated 
 heterophoria means perpetual action of 
 two or more of these basal centers, dur- 
 ing all waking hours, and in both distant 
 and near seeing. Such centers and their 
 respective muscles get no rest except in 
 sleep, or when one eye is covered or vol- 
 untarily closed. In lateral heterophoria a 
 posing of the head may bring rest to one 
 basal center, but it will demand greater 
 activity on the part of the other one, 
 whether these centers be the right and left 
 
28 The Nervo-Muscular Mechanism of the Eyes 
 
 third or the right and left fourth basal 
 centers. 
 
 It is no longer any wonder that many 
 people, who have lost one eye, claim that 
 the remaining eye is stronger than the two 
 eyes ever were. Such people were heter- 
 ophoric and their fusion centers had no 
 longer any occasion for either storing or 
 discharging neuricity, after the loss of one 
 eye. 
 
 Conjugate centers, .as already stated, 
 are never called on for the correction of 
 heterophorias, for this must be done by 
 the fusion centers. There are conditions, 
 however, that make excessive demands on 
 the conjugate centers. These conditions 
 can only be named here: asthenic ortho- 
 phoria and asthenic heterophoria of what- 
 ever kind. Sthenic orthophoria and the 
 sthenic heterophorias make less than the 
 normal demand on the conjugate centers. 
 
 In the following study of the structure 
 of the three pairs of motor nerves of the 
 eyes, these must be considered as belong- 
 ing to a person who is right-handed, whose 
 macular connections are all in the left 
 brain. Plate 1 shows that conjugate cen- 
 ters 1, 2, 3, 7, 9, 10 and 11, in the left brain, 
 send forth their fibers across the median 
 line to help form the right third nerve, 
 and that conjugate center 5 in the right 
 brain sends direct fibers to help form this 
 
The Ncrvo-Muscular Mechanism of the Eyes 29 
 
 nerve. Only half the axones from these 
 eight conjugate centers are thus directed. 
 The other half of the axones from the cen- 
 ters named, except the fifth, enter into the 
 formation of the left third nerve (See 
 Plate 2), and in this nerve will be found 
 half the axones from the left fourth con- 
 jugate center. None of the fibers, or ax- 
 ones, forming the left third nerve have 
 crossed from the opposite side of the brain. 
 The balance of the right third nerve is 
 formed by all the single axones of right 
 basal centers 1, 2, 3, 7, 10 and 11; and the 
 balance of the left third nerve is composed 
 of all the fibers from the left 1, 2, 3, 7, 10 
 and 11 basal centers. Thus, it will be 
 seen, that each third nerve is composed of 
 half the fibers from eight conjugate cen- 
 ters and all the fibres from six basal cen- 
 ters. 
 
 The construction of the fourth pair of 
 nerves is very simple, as shown in Plates 
 3 and 4 of Chart 1. The right fourth 
 has in it half the axones from the left 
 six and eighth conjugate centers and all 
 the axones from the right sixth basal cen- 
 ter. The left fourth nerve is composed 
 of half the axones from the left sixth and 
 ninth conjugate centers and all the axones 
 from the left sixth basal or fusion center. 
 All the volitional fibers of the right fourth 
 nerve have crossed, as'* shown in Plate 3; 
 
30 The Nervo-Muscular Mechanism of the Eyes 
 
 while none of those forming the left fourth 
 nerve, as shown in Plate 4, have crossed. 
 
 The construction of the sixth pair of 
 nerves is still less complicated. Plate 5 
 shows the right sixth nerve composed of 
 half the axones from th^ left fourth con- 
 jugate center and all the axones from the 
 right fourth basal or fusion center. Plate 
 6 shows the left sixth nerve composed of 
 half the axones from the right fifth con- 
 jugate center, and ail the axones from the 
 left fourth basal or fusion center. All 
 the voluntary fibers found in either of the 
 two sixth nerves have crossed on their way 
 from center to muscle. None of the fu- 
 sion fibers of any one of the three pairs 
 of motor nerves have crossed to the oppo- 
 site side. All the fibers or axones enter- 
 ing into the formation of these nerves are 
 insulated from their starting point, the 
 central cell, to their termination In the 
 muscles, so that the neuricity generated 
 by these cells may not be dissipated when 
 discharged to the muscles for controlling 
 them in their action. 
 
 The active fusion centers in the several 
 forms of heterophoria are shown in the plates 
 of Chart 3, and the last plate in Chart 2. The 
 unnumbered plate in Chart 2 shows the fact 
 that, in orthophoria, there is no excitation of 
 either conjugate or fusion centers when 
 the point of view is straightforward and, 
 
The Ncrvo-Muscular Mechanism of the Eyes 31 
 
 practically, at infinity. Both brain rest 
 and muscle inaction are shown in this 
 plate by the absence of all connecting 
 fibers. 
 
 Plate 25 shows the two fusion centers 
 that must be unremittingly active in left 
 hyperphoria and right cataphoria. These 
 are the right first and left second fusion 
 centers acting, respectively, on the right 
 superior and left inferior rectus. If the 
 condition were right hyperphoria and left 
 cataphoria, the excited fusion centers 
 would be the left first and the right sec- 
 ond, and the constantly contracting mus- 
 cles would be the left superior and right 
 inferior recti. 
 
 Plate 21 shows the excited fusion cen- 
 ters and the contracting muscles in ex- 
 ophoria, while Plate 17 shows the over- 
 worked fusion centers and their respective 
 muscles in esophoria. Plate 36 illustrates 
 the brain and muscle activity in plus cy- 
 clophoria, while Plate 37 shows the fusion 
 centers and the two muscles which are in 
 constant action in minus cyclophoria. 
 These heterophorias successfully treated 
 by operation or other means would give 
 to brain centers and muscles the restful 
 state shown in the unnumbered plate. 
 Untreated, the wear-and-tear of brain and 
 muscles must go on to the end of life. 
 
 Before closing with the study of rota- 
 
32 The Ncrvo-Muscular Mechanism of the Eyes 
 
 tions, the muscles and brain centers con- 
 cerned in each, the laws of motion must 
 be given. 
 
 LAW OF MONOCULAR MOTION 
 
 The law governing - monocular rotations 
 may be formulated as follows: 
 
 "(1) The visual axis, which is the line 
 of intersection of the planes of all me- 
 ridians, must be rotated in the plane of 
 that meridian on tvhich lie the first and 
 second points of view and their retinal 
 images. 
 
 "(2) In the plane of the horizontal, 
 or that of the vertical meridian, the rota- 
 tion must be effected around, a single fixed 
 axis, at right-angles to the rotation plane 
 and cutting it at the center of rotation — 
 if in the horiontal plane, around the verti- 
 cal axis of the eye; if in the vertical plane, 
 around the transverse axis of the eye. 
 
 "(3) In the plane of an oblique rotation, 
 whatever the degree of obliquity, the rota- 
 tion must be accomplished, around two 
 moving axes by two forces acting simul- 
 taneously, these axes being the transverse 
 and vertical axes, both at right-angles to 
 the visual axis, but neither one at right- 
 angles to any oblique rotation plane; while 
 a third force prevents any rotation around 
 the visual axis." 
 
 The law of monocular motion, since 
 
The Nervo -Muscular Mechanism of the Eyes 33 
 
 binocular vision is not in consideration, is 
 accomplished without any demand on the 
 fusion centers, just as in monocular rest 
 there is no such demand. 
 
 LAW OF BINOCULAR ROTATIONS 
 
 In binocular rotations each eye must 
 obey the law of monocular motion, but the 
 two together must obey the laiv of binocu- 
 lar rest and motion. "The twelve extrin- 
 sic muscles of normal eyes under the con- 
 trol of the nine conjugate and the twelve 
 fusion brain centers, must so relate the 
 two eyes that their two visual axes and 
 the two horizontal retinal meridians shall 
 always lie in the plane of the primary 
 isogonal circle, whether at rest or in mo- 
 tion, and that the two visual axes shall 
 converge at some point on this circle, in 
 the interest of both binocular single vision 
 and correct orientation" 
 
 Binocular rotations can best be stud- 
 ied in the light of Fig. 4. In this study 
 the two eyes will be considered as or- 
 thophoric. The line e-f of intersection of 
 the two planes of reference is the line 
 on which every object or point must be 
 located which is to be considered the pri- 
 mary point of view. If this point is at 
 infinity, the conjugate and the fusion 
 brain centers and all the ocular muscles 
 are in a state of rest. If the point is near 
 3 
 
34 The Nervo-Muscular Mechanism of the Eyes 
 
 by, only two extrinsic muscles (the inter- 
 ni) and one conjugate brain center (the 
 third) are in action. 
 
 Objects or points in space not on the 
 line e-f are secondary points of view. If 
 these points are in either the horizontal 
 or the vertical plane of reference, they 
 are cardinally related to points on the line 
 e-f. Points not in either of these planes 
 are obliquely related to their line of inter- 
 section, e-f. 
 
 The points c and d are in the horizontal 
 plane with /. In moving the visual axes 
 from / to d, the fourth conjugate center 
 and the right externus and left internus 
 are active, and each eye is rotated around 
 its vertical axis. All other centers and 
 muscles are at rest in this rotation. In 
 moving the visual axes from f to c the 
 fifth conjugate center sends neuricity to 
 the left externus and right internus. In 
 cardinal rotations, right or left, only two 
 muscles are called into action by only one 
 conjugate center. The right rotation is 
 shown in Fig. 1. 
 
 Points i and / are in the vertical plane 
 of the head with point /. In rotation of the 
 visual axes from / to i two pairs of mus- 
 cles and two conjugate centers will be 
 called into action by the will. One pair 
 of the muscles is the two superior recti 
 and the other, the two inferior obliques. 
 
The Nervo-Muscular Mechanism of the Eyes 35 
 
 The centers calling these muscles into ac- 
 tion are, respectively, the first and sev- 
 enth conjugate centers. This rotation is 
 shown in Fig. 2. The rotation from / to j 
 would be effected by the two inferior recti 
 and the two superior obliques, under the 
 influence, respectively, of the second and 
 sixth conjugate centers. In both of these 
 cardinal rotations of orthophoric eyes, 
 all other ocular muscles and brain centers, 
 not named in that connection, are at rest. 
 These rotations are around the horizontal 
 axis of the eye. 
 
 A point anywhere above the horizontal 
 plane and to the right of the vertical 
 plane, obliquely related to point /, can be 
 reached by the two visual eyes only by the 
 harmonious action of three pairs of mus- 
 cles — the two superior recti, the right ex- 
 ternus and left internus, and the right su- 
 perior oblique and left inferior oblique — 
 and by three conjugate centers, respec- 
 tively, the first, the fourth, and the eighth. 
 All other muscles and conjugate centers 
 are inactive. Two fusion centers, the 
 right first and the left third, must aid in 
 this rotation. This rotation, as shown in 
 Fig. 3, and all other oblique rotations are 
 effected around two moving axes, the ver- 
 tical and horizontal axes, by means of 
 three pairs of muscles acted on by their 
 respective conjugate centers, aided by two 
 
36 The Nervo-Muscular Mechanism of the Eyes 
 
 fusion centers. The rotation shown in 
 Fig. 3 is an example of all oblique rota- 
 tions. 
 
 All oblique rotations are around the 
 same two axes, each moving as the eye 
 rotates around the other. These two axes 
 are the vertical and horizontal axes of 
 the eyes, and these are the axes of the 
 four cardinal rotations, though in either 
 of the latter there is but one axis and it 
 is fixed throughout the given rotation. 
 
 The aim of the treatment of all forms 
 of heterophoria is to make it easy for the 
 eyes to obey the law of binocular rest and 
 motion. 
 
ROUTINE IN EYE WORK* 
 
 The title of my address presupposes prepared- 
 ness for practice. The past, in many instances, 
 would not justify this presumption, for it has 
 been notorious that " the six-weeks' postgraduate 
 course " has plunged many a man into eye work 
 without proper preparation. As out of the old- 
 time medical course of two years, which never 
 did fit one for the practice of medicine and sur- 
 gery, there occasionally grew giants — such as 
 Flint, Gross, and others — so out of a course in 
 ophthalmology all too short there have sprung 
 some men of might in our specialty. The real 
 preparation of these men began after their short 
 courses of study, under teachers, had ended, and 
 was carried on by dint of personal effort in pri- 
 vate study and meditation, long continued. 
 
 " The heights by these men reached and kept 
 Were not attained by sudden flight; 
 But they, while many comrades slept, 
 Were toiling upward in the night." 
 
 Times are changing, and the near future will 
 reveal a more perfect preparation on plans more 
 practical. Rules for governing the future teach« 
 
 •Chairman's address, read before the Section on Eye, Ear, 
 Nose, and Throat at the annual meeting of the Tennessee Stat* 
 Medical Association, Knoxville, April, 1916. 
 
38 Routine in live Work 
 
 ing of ophthalmology are now being formulated 
 by committees from the American Ophthalmo- 
 logical Society, the Section of Ophthalmology of 
 the American Medical Association, and the Acad- 
 emy of Ophthalmology and Oto-Laryngology. 
 The joint report of these committees, doubtless, 
 will demand that only graduates in medicine 
 shall be permitted to enter a specific and pro- 
 longed course in ophthalmology, in a medical in- 
 stitution authorized by law to confer degrees, 
 and that only such a' degree will entitle an appli- 
 cant to the privilege of an examination by a 
 properly constituted, lawful national board of 
 examiners, whose certificate would give him the 
 legal right to practice in any state of our Union. 
 
 We who are already in the practice need not 
 be troubled because of any demands to be made 
 on us, for the new rules will not be retroactive; 
 but we may well fear the competition of the 
 products of future teaching, unless we ourselves 
 become better grounded in the principles of 
 ophthalmology and more fully equipped for its 
 practice. 
 
 There is no specialty in medicine and surgery 
 comparable to ours in scientific depths and in 
 practical heights. The scientific principles can 
 be found in their beauty and strength only by 
 deep digging; the practical heights can be at- 
 
Routine in Eye Work 39 
 
 tained only by him who is willing to climb, and 
 to keep on climbing, though he may have stum- 
 bled often. 
 
 Whether one gets into the practice of ophthal- 
 mology through the short route of the past, and 
 straight because so short, or through the longer 
 and devious road of the future, if he wishes for 
 the best success, he must be a routinist as to 
 methods and means. Routine in eye work does 
 not mean that one should never change from a 
 method, or plan, of work, unless that method, 
 or plan, be perfect. One routine should be to 
 change from worse to better at every opportu- 
 nity. There are some perfected methods of do- 
 ing eye work, and there are some means at our 
 command that cannot be improved. I wish I 
 might be able to say this of all methods and of 
 every means ; but this cannot be said until oph- 
 thalmology, both as a science and as an art, has 
 reached perfection. 
 
 The relationship between the practitioner and 
 the patient sometimes begins when the one has 
 never seen the other, the medium between the 
 two being the written letter. The letter, long or 
 short, well written or badly composed, pertinent 
 or impertinent, pointed or without point, de- 
 mands an answer. The reply should disclaim 
 any ability to make a diagnosis without a per- 
 
40 Routine in Eye Work 
 
 sonal investigation, but should express a will- 
 ingness to do everything possible for the relief 
 of such condition as might be found on careful 
 examination. Any suggestion as to " absent 
 treatment " should be courteously declined as a 
 thing improper and impossible. An early visit 
 may be suggested or even urged, for the condi- 
 tion may be serious. Unless the patient's letter 
 contains a direct question as to fee, the reply 
 should make no mention of it. If there be a di- 
 rect question as to the fee for examination and 
 advice, the amount should be named for such 
 preliminary examination as would justify a diag- 
 nosis and include a prescription if needed. The 
 letter should state that the charge for a more 
 extended service, or an operation, if necessary, 
 can be learned before such service is rendered. 
 It is better that this understanding should be 
 had beforehand. 
 
 Uniformity in charges against those who are 
 able to pay should be a fixed routine, whether 
 the charge be named in a letter or spoken in per- 
 son. " The same fee for the same service " is a 
 splendid, practical motto. Any variation from 
 this should be either a professional courtesy or 
 an act of charity. The best charity in this re- 
 spect is to allow the patient to pay as much as 
 possible of the regular charge and then cancel 
 
Routine in Eye Work 41 
 
 the remainder. To charge a higher fee than 
 usual because one may be rich is not good rou- 
 tine. It is not good even on the ground that 
 this would enable you to do charity work for 
 others. Charity thus paid for by another is no 
 charity, hence would not be credited by the Re- 
 cording Angel. 
 
 The majority of patients come without pre- 
 vious announcement, often with the family physi- 
 cian or bearing a letter from him. If the pa- 
 tient is poor or in moderate circumstances or 
 rich, it is usually told. If poor and a charitable 
 consideration is suggested, it should be heeded. 
 No one can know the financial condition of a 
 patient better than the family physician. What- 
 ever may be the state of finances, the patient who 
 has been assured by the family physician that 
 he or she will be properly treated in every re- 
 pect is not likely to ask a question as to the 
 charge until the service has been rendered. Let- 
 ters from physicians should be acknowledged 
 with thanks, and they should be told of condi- 
 tions found and of treatment instituted for the 
 relief of their patients. Many patients come 
 without a letter of introduction and commenda- 
 tion. 
 
 In whatever manner patients may come, they 
 should be courteously met at the door by the 
 
4_' Routine in Eye Work 
 
 office girl, who, after seating them, should pre- 
 sent them with a Keller book of perforated cards, 
 every other leaf of which is nonperforated. Be- 
 tween the two leaves there should be a carbon 
 paper, with the black face toward the solid leaf, 
 with a pencil provided — better tied to the book. 
 Each patient should be asked to write his or her 
 name and address on the lowest card. The next 
 patient should write on the next card above, and 
 so on until every recent arrival shall have filled 
 a card. Each name should be taken in the order 
 of arrival. The names of attendants or chap- 
 erons should not be taken. Whether one or sev- 
 eral names have been written, only the filled 
 cards should be torn away. The next duty of the 
 office girl is to place the cards, in the order in 
 which they have been filled, under the double 
 punch in such a way that one of the holes to be 
 made shall be close to the right end of the card. 
 On the same board with the punch there should 
 be two uprights, with movable clips for opening 
 and closing them. The cards should be filed, in 
 their proper order, on the left- upright, through 
 the hole at the end of the name and close to the 
 end of the card. As others arrive, the same or- 
 der of procedure should follow. On this stand- 
 ard will appear only the names of patients not 
 yet seen. The card that is lowest always belongs 
 
Routine in Eye Work 43 
 
 to the patient next to be seen. The best method 
 of procedure now is to call, by bell tap, the office 
 girl to your desk, while you pull the bottom card 
 loose from the left standard. Reading the name 
 and address, you direct the girl to bring that pa- 
 tient in, while you place the card on the right- 
 hand standard through the untorn opening at 
 the other end of the card. Remembering the 
 name, or glancing at it again, you are enabled to 
 greet the patient by name as she enters, to 
 be seated near your desk. 
 
 This transference of cards from one standard 
 to the other is made, as patient after patient is 
 seen, until every one has been presented. As 
 each patient is retiring, the proper entering of 
 the fee should be made on the card, and either 
 the word " charge " or " paid " should be written. 
 At each subsequent bell tap the office girl could 
 bring the next patient, in order, from the car- 
 bon writing on the solid leaf, checking each name 
 as the patient is sent in. But this is not the bet- 
 ter routine. This would not insure your having 
 looked at the name, for you may have failed to 
 transfer that patient's card from the one stand- 
 ard to the other; hence the failure to greet by 
 name — a failure that would have a bad effect on 
 a new patient and a worse effect still on an old 
 patient. The main purpose of the carbon writ- 
 
44 Routine in Eye Work 
 
 ing is that it may be referred to at any subse- 
 quent time, and for this reason every solid page 
 should be dated at the top. At the end of every 
 day, after transferring all charges to the blotter 
 or daybook, the cards filed during the day should 
 be thrown away. 
 
 The routine use of the Keller registration book 
 produces the following results : ( 1 ) It insures 
 the presentation of patients in the order of ar- 
 rival ; (2) it enables the doctor to greet the pa- 
 tient by name; (3) if the patient is an old one, 
 the record may be looked into before the presen- 
 tation ; (4) it insures against failure to make the 
 proper financial entry ; (5) at the close of the day 
 the exact number of patients may be known by 
 counting the cards ; (6) a permanent carbon 
 copy of each day's record is kept for reference. 
 
 When in the consulting room, some patients 
 will hesitate to take the offered chair until they 
 know something about the cost of the consulta- 
 tion. One question sometimes asked is : " Do 
 you charge anything for the examination ? " 
 This question, doubtless, is more often asked of 
 oculists than of any other class of physicians, for 
 the reason that so-called " oculists " advertise : 
 "Examinations free." The routine answer to 
 this question should be : " If I did not charge, I 
 would have to spend all my time treating curi- 
 
Routine in Eye Work 45 
 
 osity." This statement, in such cases, should be 
 immediately followed by the naming of the usual 
 fee for a preliminary examination. Only rarely 
 will such a prospective patient depart without a 
 proper consultation. 
 
 A large number of patients, after being 
 seated, will ask : " Doctor, what will be your 
 charge for finding out what my condition is, and 
 what ought to be done for me, for I am not 
 sure that I will want treatment to-day ? " They 
 should be told the usual fee, which should always 
 be uniform, and this charge should include a 
 prescription, should the condition call for that 
 only. If this investigation is carefully made, in 
 a routine, but thorough, manner, the patient will 
 be ready and willing to submit to whatever sub- 
 sequent procedure may be advised, as soon as 
 the fee for same may have been named, whether 
 it be the fitting of glasses, operations on the 
 muscles, or other operative work. 
 
 A still larger number of patients will indicate 
 that their chief desire is to know^ the nature of 
 their cases and to obtain relief, willing to leave 
 the matter of fee for the final consideration, hav- 
 ing the conscious assurance that they will not be 
 overcharged, and this confidence should not be 
 abused. 
 
 Whether a patient belongs to one or the other 
 
46 Routine in Eye Work 
 
 of these three classes, or even if the patient be 
 known to be penniless, the same conscientious, 
 careful consideration should be given to every 
 detail of the investigation. The oculist should 
 be a good listener ; for, whether necessary or 
 not, the patient believes that the story of suffer- 
 ing and other facts of personal or family history 
 should be told. Routine listening is not dam- 
 aged by a question properly propounded. The 
 question may impress the patient that your in- 
 terest is deepening; The patient's story may be 
 cut short by a very simple little procedure, which 
 may not always be necessary, but, because of its 
 effectiveness, should be practiced. It is the pull- 
 ing down of the lower lid, first on one side and 
 then on the other, accompanied by a look into 
 the lower conjunctival fold. If this is found 
 perfectly healthy, there is but little need for 
 everting the upper lid ; but if the lymph follicles 
 are enlarged, the upper lid should be turned to 
 ascertain if trachoma bodies are present. One 
 can then proceed with the investigation, the pa- 
 tient now being pleased to answer questions only. 
 The presence of a pterygium, corneal ulcer, scar, 
 or opacity can now be noted. The size of the 
 pupil and its reaction to light should be observed. 
 The pupil may be found black or hazy, as in cat- 
 aract. No comment should now be made on any 
 
Routine in Eye Work 47 
 
 of these observations. If small, inactive pupil, 
 circumcorneal, or even general, redness, with 
 lachrymation, pain and dread of light should in- 
 dicate iritis, the touchstone of the investigation 
 should be applied — atropine solution instilled — 
 and the patient should be sent to some dark cor- 
 ner to await the effect. No dilatation at all, or 
 irregular or jagged dilatation, now justifies the 
 diagnosis of iritis. Not only the diagnosis, but 
 also the seriousness of the disease, should be 
 told; and the routine treatment should be insti- 
 tuted. 
 
 Should the pupil be dilated, inactive, and ap- 
 parently greenish, whether redness or pain ex- 
 ists or not, glaucoma should be suspected. In- 
 creased tension, whether shown to the fingers or 
 by the tonometer, would make the case more 
 suspicious ; but the diagnosis should not be given 
 until the ophthalmoscope has revealed the cupped 
 disc. In giving the diagnosis, the gravity of the 
 condition should be mentioned to either the pa- 
 tient or to a relative or near friend. The acute- 
 ness of vision, if any, should be noted. As in all 
 others, the case history should be taken. Treat- 
 ment suited to the case should be instituted. Op- 
 eration must be done if the case is acute, and 
 may be done if the case is subacute or chronic. 
 Every operator should select that method of op- 
 
48 Routine in Eye Work 
 
 erating which appeals to him most, and should 
 do it routinely — if trephining, by all means tre- 
 phine ; if LaGrange's operation, do it constantly ; 
 if the modified LaGrange — the cutting off of the 
 corneal lip — do it; if the iris-incarceration op- 
 eration, do it ; if the Graefe broad iridectomy, do 
 it. As for myself, I prefer the modified La- 
 Grange; and the more often I do it, the better 
 able I am to do it and the more successful I will 
 be in my results. 
 
 To outline my routine in connection with other 
 diseases would make this address entirely too 
 long. My main purpose, from the beginning, 
 was to outline and emphasize the importance of 
 routine work in detecting and correcting errors 
 of refraction and muscle errors. 
 
 In a given case we have found no evidence of 
 the existence of any ocular disease. The patient 
 has given a history pointing more or less strong- 
 ly to some visual defect. 
 
 Routine work of investigation should now be- 
 gin. If not already seated between the refrac- 
 tion case and the phorometer, the patient should 
 be so placed. The card of test letters should be 
 immediately in front, and distant twenty feet. 
 The patient should now be asked to read with 
 the two eyes the smallest letters possible to her. 
 The result should be noted. Then each eye 
 
Routine in Eye Work 49 
 
 should be tested alone in the same manner. The 
 fact that vision with each eye alone is 20-20 is 
 no evidence that hyperopia does not exist and 
 that astigmatism is absent; but myopia and high 
 degrees of astigmatism have been eliminated. 
 The next routine step should be to prove the 
 presence or absence of hyperopia, and this is 
 done by holding a pair of spheres, +2.00 D, be- 
 fore the eyes and noting the acuteness of vision 
 through them. If vision is 20-20 through these 
 lenses, there is a high degree of hyperopia ; and 
 if better than 20-100, there is more or less hyper- 
 opia present in one or both eyes. In a case of 
 this kind astigmatism of low degree may be 
 easily detected by means of a pair of +.50 D 
 cylinders. If, with the axes vertical, the vision 
 is more acute than when they are horizontal, 
 there is astigmatism according to the rule ; if, 
 with these cylinders, with axes horizontal, vision 
 is more acute than when vertical, there is astig- 
 matism against the rule. If, without lenses, 
 vision is low, it may be due to a very high de- 
 gree of hyperopia, which would be shown by the 
 fact that vision is improved by strong plus 
 spheres ; or it may be chargeable to myopia, 
 which will be shown by more acute vision 
 through strong minus spheres ; or the low vision 
 may depend on high degrees of astigmatism, 
 
50 Routine in Eye Work 
 
 which will be shown by increased acuity of 
 vision through strong cylinders, either plus or 
 minus, with their axes in certain positions. 
 
 The routine of the preliminary examination 
 might end here if the ciliary muscles, as once 
 claimed, were Pandora's box, out of which come 
 all evils chargeable to the eyes ; and proper steps 
 might be taken at once to prepare the patient for 
 the final examination, looking toward the correc- 
 tion of the focal errors just detected. If there 
 is but one eye, the preliminary examination out- 
 lined above is the beginning and the end. Not 
 so when there are two eyes. Not to go further 
 would mean failure in a large percent of cases. 
 
 The routine worker now turns from the trial 
 case to the phorometer, with confidence that its 
 findings will help him to render better service to 
 his patient. 
 
 A word as to the phorometer itself before put- 
 ting it to routine use. While on the floor in Den- 
 ver, in 1898, discussing the method of determin- 
 ing heterophoric conditions, I stated that the per- 
 fect phorometer has not yet been invented, but, 
 when invented, it would be built on the principle 
 that the retinal image in one eye should be undis- 
 turbed throughout any given test of the other 
 eye ; that no binocular phorometer is trustworthy. 
 Hesitating a moment, I said: "At this very mo- 
 

 Routine in Eye Work 51 
 
 ment the monocular phorometer has taken form 
 in my mind, and as soon as I return home I will 
 have it made and put to the test." Many of you 
 are acquainted with that device which was made, 
 at my suggestion, by F. A. Hardy & Co. in the 
 early fall of 1898, since which time, until recent- 
 ly, it has had no rival as a monocular instru- 
 ment. While, through the years, many have been 
 convinced that the monocular principle is the cor- 
 rect one, and that the monocular phorometer is 
 the only one worthy of trust, many others have 
 held on to the binocular idea and have used only 
 the binocular instrument. The day for the dis- 
 card of the binocular phorometer has come, and 
 the monocular phorometer is here to reign for 
 all time. The day of retirement of my own 
 monocular phorometer has come, and likewise 
 that of my cyclophorometer, which of necessity 
 is a binocular instrument ; but the principle stands 
 forever. DeZeng has eliminated from his beau- 
 tiful optophorometer the binocular feature, the 
 only thing that ever marred his instrument. In 
 its perfected state it is a monocular phorometer 
 and a cyclophorometer in combination. Its 
 beauty and utility are beyond criticism, and, at 
 the risk of damaging it, I have brought it with 
 me to show it. It is more beautiful than mine, 
 more convenient of use, and just as accurate. 
 
52 Routine in Bye Work 
 
 With the DeZeng instrument all the tests of the 
 two eyes, taken separately, can be made in six to 
 ten minutes, including the record of the findings. 
 It will quickly drive all binocular phorometers 
 from the field. 
 
 Having said this much about the monocular 
 phorometer, we can now take up the routine of 
 its use. The test object should be a small point 
 of light, though it may be the blaze of an ordi- 
 nary candle. It should be distant from the pa- 
 tient twenty feet — practical infinity. . The pupil 
 must not be under the influence of either a mydri- 
 atic or a myotic, but the two eyes should be as 
 set forth in the routine test for determining the 
 presence or absence of focal errors, and, if pres- 
 ent, their character. The uninfluenced pupils 
 and ciliary muscles, throughout the preliminary 
 test, are implied in the expression : " The rou- 
 tine worker now turns from the trial case to the 
 phorometer." 
 
 With the DeZeng monocular phorometer 
 turned into position, as if the optometer part was 
 to be used, but with its cells empty, the spirit 
 level should be regulated and one eye or the 
 other chosen for the testing of the tonicity of the 
 four recti muscles in the four cardinal directions 
 only. Take the right eye, since in making rec- 
 ords " O. D." is always written first. There 
 
Routine in Eye Work 53 
 
 should be nothing but empty space in front of 
 the left eye, and this, throughout the test of the 
 right eye, should be the fixing eye. The ten- 
 degree prism should be turned into position, base 
 in, before the right eye, which will throw the 
 retinal image nasalward, outside the fusion area. 
 The false object will be thrown directly to the 
 right, and it should be perfectly level with the 
 true or fixed object. If not level,, it is because 
 muscle tonicity has turned the eye either up or 
 down, the false object having gone in the oppo- 
 site direction. Want of levelness demands that 
 the rotary prism should be turned into position, 
 the rotary screw directly out, and the index of 
 prism at zero. The prism is now so rotated as 
 to bring the false object level with the true or 
 fixed object. The extent of this rotation is 
 noted; and if the false object had to be elevated, 
 the note would read R. hyperphoria " so many " 
 degrees; but if the false object had to be de- 
 pressed, the reading would be R. cataphoria " so 
 many " degrees. Either now, or as well at the 
 end of the tonicity tests of the recti muscles, the 
 proof test for hyperphoria should be applied. 
 It consists of a Maddox double prism, 3 to 5 
 degrees each, to be held, base line horizontal, 
 first before one eye and then before the other, 
 allowing the patient to look through only one of 
 
54 Routine in Eye Work 
 
 the prisms at a time. Raising and lowering the 
 prisms, the patient is asked to name the position 
 which makes the false object nearer the true. 
 If there is right hyperphoria, the false object 
 will fuse with the true or be near it through the 
 upper prism, but far removed when seen through 
 the lower prism by the right eye. The reverse 
 will be true when the double prism is moved up 
 and down before the cataphoric eye. If the false 
 and true objects are practically the same distance 
 apart, as the double prism is raised and low- 
 ered before each eye, there is no vertical imbal- 
 ance. 
 
 The ten-degree prism must now be turned out 
 of the way, and the six-degree prism, base up, 
 should be turned into position. The rotary prism 
 is now turned so that the screw is directly up 
 and the index at zero. The retinal image for 
 this eye is now displaced directly above, beyond 
 the fusion area, so that the false object would 
 appear below, and should be directly below the 
 true or fixed object. If directly in line, there is 
 lateral orthophoria for distance ; but if not verti- 
 cally beneath, the rotary prism must be made to 
 move it into that position. The index will mark 
 the extent of the rotation. If the false object 
 had to be moved from the left, the record would 
 read R. exophoria " so many " degrees ; but if it 
 
Routine in Eye Work 55 
 
 had to be moved from the right, the reading 
 would be R. esophoria " so many " degrees. 
 
 Again revolving the rotary prism into neutral- 
 ity, the convergence test, by means of a dot with- 
 out lines, must be made. The false dot standing 
 directly under the true would show lateral ortho- 
 phoria in the near, for the card on which is the 
 dot should be held at the reading distance, with 
 the dot in the horizontal plane with the eyes. 
 Should the false dot not be in the vertical plane 
 with the true dot, the rotary prism should be 
 made to move it into that plane. If it had to be 
 brought from the left, the reading should be R. 
 exophoria " so many " degrees in the near ; but 
 if from the right, it should be recorded R. eso- 
 phoria " so many " degrees in the near. Since 
 this is the convergence test and both interni have 
 received the same impulse from the convergence 
 center, the record could leave out " R.," if it be 
 the right eye under test — that is, if the false im- 
 age belongs to the right eye ; and the same should 
 be done in the near test of the left eye. In either 
 case want of convergence power would be re- 
 corded, " Exophoria in the near ; " and excess 
 of convergence would be recorded, " Esophoria 
 in the near." The far and the near tests always 
 correspond when the ciliary muscles have normal 
 tonicity; they are always out of harmony when 
 the ciliary muscles are wanting in tonicity or 
 
56 Routine in Eye Work 
 
 when they have excessive tonicity. The right 
 eye having been tested, the left may be tested in 
 the same manner and proper records made. 
 
 The recti muscles of both eyes having been 
 tested as above set forth, the next step in the 
 routine use of the phorometer should be to deter- 
 mine the presence or absence of cyclophoria, and, 
 if present, whether plus or minus. To do this, 
 the rods on both sides must be placed in front 
 of their respective eyes, with the axes of the 
 rods vertical, so that the streak of light may be 
 horizontal for each eye alone. The six-degree 
 prism, base up, must be placed in position be- 
 fore one eye, so as to throw the retinal image 
 of that streak entirely above the fusion area, the 
 streak itself being below. If the two streaks are 
 parallel, the obliques have normal tonicity. If 
 these streaks diverge on the side opposite the 
 prism, there is plus cyclophoria ; but if they di- 
 verge on the side corresponding to the prism, 
 there is minus cyclophoria. In either case the 
 rod in front of the prisms should be so revolved 
 as to make the two streaks parallel. The index 
 will name the amount of the error, and the direc- 
 tion of its rotation will name the kind of error. 
 The eye behind the displacing prism is the one 
 under test. The one eye having been tested, its 
 displacing prism should be turned out of the way, 
 
Routine in Eye Work 57 
 
 and the six-degree prism belonging to the other 
 side should be placed for testing it. Usually 
 when one eye shows plus cyclophoria, the other 
 will show the same ; and since this is the case, 
 the record would read plus (or minus) cyclo- 
 phoria " so many " degrees, leaving out the let- 
 ters " R " and " L." 
 
 Immediately following the tonicity tests of the 
 twelve ocular muscles and the taking of the con- 
 vergence power of the interni, the duction power 
 of each individual muscle should be ascertained. 
 The routine order should be : First, superduc- 
 tion ; second, subduction ; third, abduction ; 
 fourth, adduction; fifth, minus cycloduction ; 
 sixth, plus cycloduction. In taking the duction 
 power of the recti muscles, the rotary prism 
 alone is necessary, and this before one eye only. 
 The test object should be a point of light or even 
 a candle blaze. This testing of the recti muscles 
 should be in the four cardinal directions only. 
 For the vertical ductions the screw of the rotary 
 prism must be horizontal and the index of prism 
 must be at zero. Rotating the apex of the prism 
 up, the retinal image of the test object is being 
 moved downward. The superior rectus makes 
 the macula keep pace with the moving image to 
 the extent of its power, thus preventing diplopia. 
 The point reached by the index at the moment 
 
58 Routine in Eye Work 
 
 diplopia occurs is the measure of superduction, 
 which should be noted as " so many " degrees 
 R. (or left) superduction. Returning the index 
 to zero, the apex should now be rotated down, 
 which carries the retinal image upward, the in- 
 ferior rectus compelling the macula to keep pace 
 with the moving image so long as possible, thus 
 preventing diplopia. At the moment of diplopia 
 the index points to the degree mark of subduc- 
 tion, to be noted as " so many " degrees of R. (or 
 L.) subduction. 
 
 Moving the screw into the vertical position 
 and placing the index at zero, the phorometer is 
 ready for taking horizontal duction, both right 
 and left. Rotating the prism apex out, the reti- 
 nal image in that eye is made to move directly 
 nasalward, while the external rectus is compell- 
 ing the macula to keep pace with the moving 
 image in the interest of binocular single vision. 
 At the moment of diplopia the index points to 
 the degree of abduction for that eye, and the note 
 should be made " so many " degrees of R. (or 
 L.) abduction. Returning the index to zero, the 
 apex of the prism should now be rotated nasal- 
 ward. This will cause the retinal image to move 
 directly outward, but the internal rectus will 
 make the macula keep pace with the moving 
 image to the extent of its power, and up to this 
 
Routine in Eye Work 59 
 
 limit there will be binocular single vision. When 
 the rotation passes the limit of power, diplopia 
 at once manifests itself. The index will then 
 stand at the point marking the extent of the ro- 
 tation of the eye, which should be noted as " so 
 many " degrees of R. (or L.) adduction. 
 
 The duction power of all the recti of one eye 
 having been taken, the rotary prism for that eye 
 should be turned out of the way, and that for 
 the other eye should be placed ready for action. 
 Precisely the same steps should be repeated in 
 determining the duction power of its four recti. 
 The same records should be noted as in connec- 
 tion with the tests of the muscles of the other 
 eye. The results of these tests must be com- 
 pared with what is known to be the normal duc- 
 tion power of these several muscles. 
 
 In taking cycloduction, the rods only must 
 stand before the two eyes, and their axes must 
 be vertical. The rods should be the same color 
 on each side, for otherwise the fusion effort on 
 the part of the obliques would fall short of the 
 normal to them. Only one rod should be rotated 
 at a time. Rotating the axis out tests the power 
 of the inferior oblique of that eye. The instant 
 that the streak of light doubles, the rotation 
 should cease. The index now points to the de- 
 gree mark on the scale, showing the extent of 
 
60 Routine in Eye Work 
 
 the wheel-like motion effected by the inferior 
 oblique of that eye, and should be noted " so 
 many " degrees of R. (or L.) plus cycloduction. 
 The axis of the rod having been returned to zero 
 for a moment's rest, it should now be rotated 
 toward the nose up to the point of doubling the 
 streak. The index at this point indicates the ex- 
 tent of the wheel-like rotation effected by the 
 superior oblique of that eye, and it should be 
 noted as "so many " degrees of R. (or L.) minus 
 cycloduction. 
 
 The cycloduction of the one eye having been 
 taken, the rod before it should be set in the verti- 
 cal, and the rod before the other eye should be 
 rotated first out, for determining its plus cyclo- 
 duction, and then in, for showing the minus 
 cycloduction. These cycloductions should be 
 compared with what is known to be normal. 
 
 It should be clearly understood that cardinal 
 ductions are measured in " degrees of prism," 
 while cycloductions are measured in " degrees of 
 arc. 
 
 If the tonicity tests and the duction measure- 
 ments are so nearly normal that no operation 
 would be indicated, the preliminary examination 
 may end here. 
 
 The tonicity tests having shown a high degree 
 of heterophoria, routine would call for the plac- 
 
Routine in Eye Work 61 
 
 ing of a deep-red glass before one eye. Should 
 this cause diplopia, the case is clearly one for 
 operation. The cardinal versions should now be 
 taken, either by means of the tropometer or the 
 perimeter. Oblique versions need never be taken. 
 The cardinal versions should be noted — up, 
 down, right, left. " Superversion," " subver- 
 sion," " abversion," and " adversion " are all 
 good terms and in harmony with other nomen- 
 clature. In order to reach a correct conclusion 
 as to what muscle should be operated upon in a 
 given case of heterophoria, and whether the op- 
 eration should be a partial tenotomy of the 
 stronger muscle or a shortening of the weaker 
 muscle, one or both, the tonicity, duction, and 
 version tests must all be compounded, and each 
 test must be given its proper value. 
 
 If a given case is one of heterotropia, the to- 
 nicity and version tests only are possible. Duction 
 is out of the question, because of the absence of 
 binocular single vision. Vision in one eye may 
 be so low as to make the tonicity tests very dif- 
 ficult, if not impossible ; but they should be at- 
 tempted in every case. In this a red glass in 
 front of the dull eye will be helpful. Version 
 tests are not so important in cases of heterotro- 
 pia as in cases of heterophoria. 
 
 The most important step in the study of any 
 
62 , Routine m Bye Work 
 
 case of heterotropia, unless one of the eyes is 
 mentally blind, is the fusion test. If the two 
 images cannot be brought together by the rotary 
 prism, binocular single vision can never be es- 
 tablished by any operative procedure. This is es- 
 pecially true of squinting eyes, with vision about 
 as good in one eye as in the other — cases of an- 
 tipathy to binocular single vision. 
 
 When one eye is totally blind or absent, the 
 preliminary test is a very short one and consists 
 in first placing a +2.00 sphere before the seeing 
 eye and thus determine if it is hyperopic, or a 
 — 1.00 or — 2.00 to determine if it is myopic, and 
 next hold a +.50 cylinder, axis first vertical and 
 then horizontal, to determine the absence or pres- 
 ence of astigmatism. 
 
 Now the patient is ready to be sent into the 
 waiting room to be prepared for the final exam- 
 ination. The routine use of homatropine, gr. 
 viii to distilled water one fluid ounce, for putting 
 at rest the ciliary muscles, is the most satisfac- 
 tory agent, both to the patient and to the practi- 
 tioner. One drop in each eye every three to five 
 minutes until ten drops have been instilled into 
 each eye should be the rule in all patients under 
 forty-five years of age. From the age of forty- 
 five to forty-eight, five to seven drops would be 
 sufficient. Beyond forty-eight, one drop should 
 
Routine in Eye Work 63 
 
 be put in each eye. Patients will often plead 
 that " drops " be not used, not understanding 
 the " why and wherefore." If the explanation is 
 not accepted, declination to further investigate 
 should be made. They will say, sometimes, that 
 opticians claim that " drops " are not necessary, 
 but even harmful. This should be met by the 
 statement : "Any work done without the drops 
 is guesswork, and this I cannot afford to do. I 
 cannot do the further work unless you submit 
 to the use of the drops, nor can anybody else do 
 it as it should be done without them. They are 
 not harmful." The necessity for enforced rest 
 of the ciliary muscles in those under forty-eight 
 years should be made clear, and the importance 
 of detecting disease processes in the older should 
 be emphasized, a wide-open pupil being essential 
 for this. Rarely will one refuse to submit. 
 
 The routine of drops having been completed, 
 the patient is ready to be returned to the consul- 
 tation room for the final examination. While 
 the ophthalmometer might have been used as a 
 part of the preliminary examination, since its 
 findings are not altered by the mydriatic, it seems 
 better to use it immediately before resorting to 
 the trial lenses. The value of the ophthalmom- 
 eter is now universally conceded, which consists 
 in locating the axis of the astigmatism and in 
 
64 Routine in Eye Work 
 
 showing the quantity usually within .50 D. The 
 skillful use of trial cylinders a little later will 
 show if lenticular astigmatism is a complication. 
 The ophthalmometer findings should be noted as 
 made. Retinoscopy in children and in the un- 
 lettered is essential, and is of value in all cases. 
 
 While the room is darkened, other patients in 
 process of preparation by the mydriatic, in what- 
 ever stage, should be brought in and measured 
 with the ophthalmometer and then returned to 
 the waiting room, to be recalled in the same or- 
 der later. 
 
 Now the trial case must be appealed to as a 
 finality in order that proper lenses may be or- 
 dered. With the trial frames properly placed, 
 the opaque disc should be placed before the right 
 eye. The letters called with the left eye shows 
 the unaided acuteness of vision for that eye. If 
 worse than the vision shown in the preliminary 
 test, the appeal must be made to the plus lenses ; 
 if no worse than the vision shown in the prelimi- 
 nary test, minus lenses, spherical and cylindrical, 
 must be resorted to. 
 
 I would have you view the test case for a mo- 
 ment as to the arrangement of the lenses. The 
 cylinders all have their handles at 35 degrees to 
 the axis, those in one row being to the right of 
 the axis and those in the other row to the left of 
 
Routine in Eye H'ork 65 
 
 the axis. The former should all be in the right- 
 hand row, and the latter all in the left-hand row. 
 For this arrangement of handles we are indebted 
 to A. E. Prince. The convex cylinders in the 
 right row should be used in testing the left eye, 
 and those in the left row for testing the right 
 eye in astigmatism according to the rule. When 
 these cylinders are thus placed, with axes at 90 
 degrees, the handles will be up and out 35 de- 
 grees. The concave cylinders in the right row 
 should be used for the right eye, and those in the 
 left row for the left ; for thus used, when their 
 axes are at 180 degrees, the handles will be up 
 and out 35 degrees. In astigmatism against the 
 rule the order of use would be reversed. The 
 full diopter spheres and cylinders in all the right- 
 hand rows should have their handles turned to 
 the left, which adds greatly to the convenience 
 of handling both the full and fractional lenses. 
 
 Hyperopia being suspected, in the front cell 
 should be placed the plus cylinder indicated by 
 the ophthalmometer, less .50 D, with its axis in 
 the position located by it. In the back cell should 
 be placed, by guess, the plus sphere indicated 
 by the acuteness of vision through the cylinder 
 only. Now with a +.50 D in the left hand and a 
 — .50 D in the right hand, they should be held 
 alternately in front of the combination already 
 5 
 
66 Routine in Eye Work 
 
 in the frame for determining if the first sphere 
 must be increased in strength or must be made 
 weaker. Thus proceeding, it is not long until the 
 sphere of proper strength has been found. By 
 means of either a +.50 cylinder or a — .50 
 cylinder it may be shown quickly if the original 
 cylinder is of proper strength or must be made 
 stronger or weaker, and by use of the two it 
 may be shown if the sphere must remain the 
 same as already shown or be changed in har- 
 mony with a change in the strength of the cylin- 
 der. 
 
 The left eye having been thus tested, the 
 opaque disc should be placed before it in the 
 extra cell in front of the cylinder, and the test 
 of the right eye should be accomplished in the 
 manner outlined in the correction of the left eye. 
 
 The combinations determined by the trial 
 lenses and the acuteness of vision obtained should 
 be recorded. The pupillary distance and the 
 bridge measurement must be accurately taken 
 and recorded. If the patient is forty-five or 
 older, the presbyopia for the given age must be 
 entered. These things are all to be done without 
 consulting the will of the patient ; but in the 
 choice of frames, both as to character and qual- 
 ity, the patient's desire must be gratified. 
 
 When ready to write the order for the glasses, 
 
Routine in Eye Work 67 
 
 the record as a whole must be studied. Should 
 two cases be exactly alike as to spherical correc- 
 tion, but different as to adjustment of the lateral 
 muscles, one esophoric and the other exophoric, 
 the plus correction for the former should be full, 
 but for the latter a deduction should be made 
 from the plus correction. The reverse would be 
 true of the same two cases if minus sphericals 
 stood in the record and the lenses are intended 
 for near use. A full minus correction is always 
 proper for distant wear. In making the order, 
 the strength of the astigmatic correction should 
 be accurately copied in all cases. If there is a 
 hyperphoria of quantity too slight to demand op- 
 eration, the lens for the hyperphoric eye should 
 be ground on a prism of proper strength, base 
 down. The lens for the cataphoric eye should 
 not be prismatic. Esophoria and exophoria, not 
 requiring operation, should be helped by mak- 
 ing both lenses prismatic to an equal extent, the 
 bases for the former being out and for the lat- 
 ter being in. This could be done by adding to or 
 taking from the pupillary measurement, by de- 
 centering the lenses in or out, or by having each 
 ground on a proper prism. While the record 
 should be copied as to the strength of required 
 cylinders, a complicating cyclophoria would jus- 
 tify a slight change of axes. If there is plus 
 
68 Routine in /:\v Work 
 
 cyclophoria and the record shows plus cylinders 
 converging, they should be ordered less converg- 
 ing; but if diverging, the order should call for 
 greater divergence. The variation, however, 
 should rarely be more than 5 degrees for each 
 cylinder. In cases of astigmatism against the 
 rule, in changing the axes of plus cylinders, the 
 reverse of the rule given above, known as the 
 N. C. Steele rule, should be observed. In either 
 case, should the cylinders be minus, the reverse 
 of all said above about plus cylinders would be 
 the order. 
 
 The patient should be told that high degrees 
 of a muscle error, or any combination of muscle 
 errors, demand operations. A moderate want of 
 tonicity of the recti muscles may be remedied by 
 rhythmic prismatic exercise, while such a condi- 
 tion of the obliques may be cured by the same 
 character of exercise by means of weak plus or 
 minus cylinders so placed as to call into action 
 the weak obliques. Deficient convergence power 
 should be treated by candle exercise — moved 
 from arm's length to a point seven inches from 
 the eyes, also rhythmic in character. Want of 
 ciliary power should be remedied by exercise 
 with weak minus spherical lenses. 
 
 There are some important points about bifo- 
 cals which should be routinely observed in mak- 
 
Routine in Eye Work 69 
 
 ing the order. Bifocals should never be given 
 if there is much difference in the spherical re- 
 fraction of the two eyes, for such patients must 
 learn to look through the lens centers both in 
 far and near seeing. Perfection bifocals and the 
 Franklin divided lenses have the advantage over 
 all others in that the cutting can be done, and 
 should be done, so that the centers of the upper 
 and lower parts may coincide. In these combi- 
 nations the eyes glide from one part to the other. 
 In the fused and cemented bifocals the centers 
 of the upper and lower parts cannot coincide ; 
 hence in passing from one to the other the eyes 
 must jump. In any form of bifocals the centers 
 of the reading lenses must be on the same hori- 
 zontal line; otherwise comfortable near work 
 through them cannot be done. 
 
 After lenses have been finished, they should 
 always be inspected ; and if any error has been 
 made in grinding or cutting, it should be cor- 
 rected. One of the most important things in 
 the inspection is the proper centering of lenses, 
 whether for distant or near use ; and especially 
 is this important as to the reading part of bifo- 
 cals of whatever kind. 
 
 One of the most important things in the whole 
 routine of eye work is the delivery of the lenses 
 to the patient, which should never be done with- 
 
70 Routine in Eye Work 
 
 out explicit instructions on two points: (1) A 
 straight edge should always pass through the 
 four joints of spectacles, or should coincide with 
 the long axes of the eyeglasses; (2) whether the 
 lenses are in spectacle frames or eyeglass trap- 
 pings, they must always be level in front of the 
 eyes and equally distant from them ; and if in- 
 clined at all, this should be slightly out at the top. 
 
 Many a complaint comes to an oculist either 
 because these points have not been impressed or 
 because they have not been observed. If a pa- 
 tient should ask for a guarantee (which should 
 never be granted), the above rules should be 
 doubly or trebly impressed. 
 
 There is nothing simple about the work of cor- 
 recting visual defects and muscular deficiencies, 
 and it should be unlawful for any one to engage 
 in this practice who is not educated medically 
 and scientifically. 
 
Mydriatic No Mydriatic 
 
 c o o 
 
 O 3 p 
 
 a" » c 2. S. o' SL 
 
 ^ 2. ^ o o sr 
 
 o ?• SL 3 3 J _ . 
 
 T3 
 
 3 --^^ 
 
 ' * f - " 3D * 
 
 r 50 • P 1 m 
 
 w b P P < < 
 
 3= II II 
 •a 
 
 ■i 
 
 '-, 1 cL cL S- 3- 
 
 : 1- o o 
 
 ST nT 
 
 3 3 
 
 CO 
 
 c 
 
 CO 
 
 CO 
 
 X 
 
 
 c 
 
 "0 
 
 c 
 •a 
 
 T3 
 
 •i 
 
 rt 
 
 « 
 
 
 < 
 
 ►1 
 
 ^ 
 
 *0 
 
 n 
 
 Q- 
 
 a- 
 
 p- 
 
 
 c 
 o 
 
 c 
 o 
 
 o 
 
 1 
 
 O 
 
 3 
 
 5' 
 
 3 
 
 5' 
 
 3 
 
 (B 
 
 < < 
 
 CO c c W CO » 
 
 
 
 0) 
 T3 
 
 3" 
 O 
 
 ty cr c c oj 
 
 < < tr tr t) 
 
 f» r» a- cl. p- 
 
 |. 2- § g g. 
 
 o o n - . c. 5> ^ a- s- 
 
 co co 3 3 o o' 
 
 n n 3 3 _(_ J_ 
 
 •o "0 
 
 > 
 
 <3 £ „ -° -° ° 2 *» 
 
 p " * *-r r - £ i i f .f 
 
 3 ° 
 
 3 3 
 
 C C ~ o 
 
 o o 
 
 o' o' 
 
 3 3 
 
 2 3 g * ^ ^ 
 
 »P O 3-3-3-3- 
 
 > > -° -° ++++ > 
 
 < < CL CL ^ ^-" ^2? *-" *-" CL 
 
 ^ » DL Ou -° °-. ~° 0©00 =T 
 
 co 3 c C m PT1 <"> O O <-> 2 
 
 3 3 S-' S' O O ' • • ' 
 
 *0 T3 B 3> 9 cp 
 
 O O 
 
 3 3 
 
 a- sr x x x x 
 o o • • • • 
 
 5' 5>* 
 
 << v; cu ** £ 
 
 CL CL 
 
 C C 
 
 o o 
 
 O O 
 3 3 
 
 o o o c 
 
 ■- 1 I 
 
 + 1+5 1 
 
 r r 
 
 + i + 
 
$4.00 OPHTHALMIC MYOLOGY $4.00 
 Second Edition. 
 
 The first chapter, on " Fundamental Princi- 
 ples," has been enlarged from 54 to 145 pages, 
 and has been illuminated by 23 additional cuts. 
 
 A study of the Ocular Muscles from the mus- 
 cle side of the questions, including the physics of 
 ocular adjustments and motions. This book and 
 its companion volume, " Ophthalmic Neuro- 
 Mvology," are -the only books, on the eye mus- 
 cles, in any language, based on the correct fun- 
 damental principles, as set forth in Chapter 1. 
 
 Of these principles, Black, in Colorado Medicine, says: "The 
 author is right. He has literally knocked Helmholtz's theory 
 into a cocked hat." 
 
 Wiener, in Annals of Ophthalmology, says: "The points 
 at issue so logically and concisely depicted on pages 32 to 34 are 
 unanswerable. An ophthalmologist not taking the opportunity 
 of studying this volume is doing himself an injustice." 
 
 Menacho, in Archivas de Oftalmologia, Barcelona, says: 
 "It is a profound work, and we hope soon to see it appear in a 
 Spanish translation for the diffusion of such useful knowledge 
 among our people." 
 
 London Lancet: "It is well worthy of the consideration of 
 the learned in these matters." 
 
 Wurdemann, in Ophthalmology, says: "Thorough study of 
 the author's reasonings leads a student to an acceptance of his 
 propositions and their application in practical work." 
 
 Southern Medical Journal : " It seems to the reviewer that 
 the position assumed in the first chapter is impregnable and the 
 statements unanswerable." 
 
 Dr. Daniel, Professor of Physics, Vanderbilt University, 
 says: " Having given the subjects treated some attention in 
 friendly association with the author, I am convinced that in 
 ' Ophthalmic Myology ' Savage teaches the truth." 
 
 Published by the Author, G. C. Savage, M.D., Nashville, Tenn. 
 
 Printed by McQuiddy Printing Company, Nashville, Tenn. 
 
$2.50 $2.50 
 
 OPHTHALMIC NEURO-MYOLOGY 
 
 A study of the Ocular Muscles from the brain 
 side of the questions. The late Swan. M. Bur- 
 nett said : " I am charmed with the clearness and 
 directness with which you have put the problems 
 and their solution." 
 
 Hess, of Wurzburg, Germany, says : " I wish 
 to tell you how excellently you have treated the 
 subject, and to congratulate you that you have 
 succeeded to make clear these most difficult 
 questions." 
 
 Snell, Sheffield, England, said : " It seems to 
 me that your views are correct." 
 
 Published by the Author, G. C. Savage, M.D., Nashville, Tenn. 
 
$10.00 $10.00 
 
 THE MUSCLE INDICATOR 
 
 This device, shown on page 15, reduced in 
 size and otherwise improved, is manufactured 
 and sold by 
 
 Joseph C. Snodgrass, 
 167 Fourth Avenue, North, 
 
 Nashville, Tenn. 
 
 It shows every phase of every Ocular Muscle 
 and every combination of Ocular Muscles — nor- 
 mal, abnormal, or pathological. With " Oph- 
 thalmic Myology " and " Ophthalmic Neuro- 
 Myology " as textbooks, any medical mind, 
 aided by the Muscle Indicator, may become mas- 
 ter of the muscle study. 
 
THE MONOCULAR PHOROMETER AND 
 THE CYCLOPHOROMETER 
 
 are the most reliable means for testing the 
 tonicity and the duction power of all the Oc- 
 ular Muscles. 
 
 E. B. Meyrowitz, New York, and F. A. 
 Hardy & Co., Chicago, manufacture the two de- 
 vices separately, but both to be used on the same 
 stand. The two instruments, with one stand, can 
 be had of either firm for $50.00. The DeZeng- 
 Standard Company, Camden, N. J., will soon be 
 manufacturing The Monocular Phorometer and 
 The Cyclophorometer in a most convenient and 
 beautiful combination, to be used on a floor 
 stand or wall bracket. This instrument will be 
 much more costly, and cannot be sold for less 
 than $100.00, probably more. 
 
The Keller book of individual cards for office 
 use is manufactured by D. F. Keller & Co., Chi- 
 cago, 111., 621-631 Plymouth Court, to whom all 
 orders should be sent. They are very valuable. 
 
 The record blanks on the last page of the ad- 
 dress, "Routine in Eye Work," are manufac- 
 tured and sold by Shields-Farris Printing Com- 
 pany, Nashville, Tenn., " 143 Sixth Avenue, 
 North. They are in pads of 100 and can be had 
 for 25 cents per pad, in lots of one to four ; 24 
 cents, in lots of five to seven ; and 23 cents, in 
 lots of eight to ten. 
 
QPTo 
 
14 DAY USE 
 
 RETURN TO DESK FROM WHICH BORROWED 
 
 OPTOMETRY LIBRARY 
 
 This book is due on the last date stamped below, or 
 
 on the date to which renewed. 
 
 Renewed books are subject to immediate recall. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 LD21 — 32m — 1,'75 General Library 
 (S3845l)4970 University of California 
 
 Berkeley 
 
 ^