THE LIBRARY OF THE UNIVERSITY OF CALIFORNIA LOS ANGELES GIFT OF Mrs. Clifford B. Walker THE LIBRARY UNIVERSITY OF CALIFOBNIA LOS ANGELES STEREOSCOPIC TREATMENT OF HETEROPHORIA AND HETEROTROPIA Designed to Accompany the Phoro-optometer Stereoscope and the Wells Selection of Stereoscopic Charts By DAVID W. WELLS, M.D. ' Member of A. M. A. and A. I. H. Associate Professor of Ophthalmology, Boston University Medical School Ophthalmic Surgeon, Massachusetts Homoeopathic Hospital, Boston Oculist, Newton (Mass.) Hospital Author of "Psychology Applied to Medicine" New York E. B. MEYROWITZ, Publisher 1912 Copyright, 1912, by E. B. Meyrowitz, New York Library WIO PREFACE. I \ I Ut - CONCERNING the clinical importance of hetero- phoria ophthalmologists are not agreed. As a protest against the extravagant claims made by some enthusiasts, there has arisen a class of eminent practitioners whose members abso- lutely ignore the subject and omit all tests for imbalance, unless there exists actual hetero- tropia. The author believes he occupies a middle ground, and that the opinions herein expressed are conservative. The orthoptic treatment of heterotropia is not always successful, but there is a growing con- viction that the surgeon who rests content with securing a cosmetic cure has not discharged his whole duty to his patient. It is unfortunately still true that the majority of heterotropic cases are not seen by the oph- thalmologist until the condition is quite firmly established. No opportunity should be lost to warn the family physician that the time to begin treatment is the minute the deviation is noticed. Believing that the cases of heterophoria requiring relief are much more numerous than those of actual heterotropia, the greater part of this essay will be devoted to the former con- dition. 635953 IV PREFACE. For the benefit of the beginner in ophthal- mology a brief summary is given of the impor- tant points of binocular vision, the factors upon which depends orthophoria, the causes of het- erophoria, and a discussion of the different methods of testing. While the treatment IKK presented is principally stereoscopic fusion training, other adjuvants are advised. The stereoscopic method is outlined with consider- able detail, and is the result of several years' experience. It is earnestly hoped that many others may find in the phoro-optometer stereo scope and the charts here described that same degree of satisfaction which they afford to the author. If the instructions seem more didactic than is consistent with good taste, he can only plead that he is attempting to lay before the reader his own method, and would gladly welcome any suggestions for improving it. Believing that the limitations of the orthoptic treatment of heterotropia should be thoroughly understood, the indications for operative inter ference have been briefly stated. D. W. \V. HOTEL WESTMINSTER, COPLEY SQUARE. BOSTON. .Fan.. I'.H-J. CONTENTS. PAGE CHAPTER 1 7 Binocular Vision Law of Corresponding Points Semi-decussation Fusion Faculty. CHAPTER II 12 Ortliophoria Heterophoria Stevens' Photometer Savage's Monocular Phorometer Wells' Handy Phorometer Prentice Prismometer and Phoro- meter Screen Test Duction Causes of Hetero- phoria Symptoms of Heterophoria. CHAPTER III 23 Treatment of Heterophoria Prismatic Glasses Operative Muscle Training Fusion and Muscle Training Phoro-optometer Stereoscope. CHAPTER IV 32 Stereoscopic Treatment of Exophoria Author's Card for Measurement of Stereoscopic Heterophoria Amplitude of Fusion Recovery Exercises Home Exercises The Suppressed Eye Controlled Read- ing Author's Device Number of Cases Treated and Results. CHAPTER V 54 Stereoscopic Treatment of Esophoria May Be an Expression of Convergence Insufficiency Fusion Training Same as for Exophoria Amplitude Training the Reverse or May Be Same as for Exophoria. (v) VI CONTENTS. I'AUK CHAPTER VI 59 Treatment of Hyperphoria Stereoscopic Treatment Not Practicable Prism-duction Treatment Au- thor's Cards for Right and Left Hyperphoria. CHAPTER VII 62 Stereoscopic Treatment of Heterotropia of Concomi- tant Esotropia The Amblyoscope Autlim '- Deviometer The Percentage of Cures The Time for Operation Treatment jf Alternating Esotropia Treatment of Exotropia. CHAPTER VIII. Concluding Remarks Theories Psychic Element The Choice of Cards Superabundance of Ampli- tude a Valuable Reserve. CHAPTER I. BINOCULAR VISION. LAW OF CORRESPONDING POINTS. SEMI-DECUSSATION . FUSION FACULTY. BINOCULAR single vision is a rather intricate psychic faculty dependent on certain exact physical conditions. "With each eye we see a separate object and, according to the law of corresponding points, it is necessary that the images of the object fall upon corresponding points of the two retinae in order that single binocular vision may be realized. For central vision these points are the two maculae, and for peripheral vision these points must be equally to the right, to the left, above or below the two maculae. LEFT EIGHT FIG. 1. CORRESPONDING RETINAL POINTS. (LE CONTE.) (7) 8 STEREOSCOPIC TREATMENT OF The field of binocular single vision is that portion of the two fields which can be seen by both eyes simultaneously, the projection of a single impression depending upon the seini- decussation of the fibers of the optic nerve, which occurs only in man and the higher apes. Semi-decussation is, therefore, the first physical essential. FIG. 2. SEMI-DECUSSATION OF OPTIC NERVE. To explain this, and the clinical facts of homi- anopsia, it is assumed that at the chiasm each neuron divides into two, one of which crosses to the nasal side of the opposite eye, while the other goes to the temporal side of the eye on the same side, the end organs occupying corre- sponding points in the two retinas. A second physical requisite is the perfect coordination of the twelve extrinsic muscles. HETEEOPHORIA AND HETEROTROPIA. 9 that the eyes may be so directed to any point in the binocular field, that the images shall fall on corresponding points. AVlien it is realized that a deviation of less than a millimeter* in the position of correspond- ing points means diplopia for small objects, it is almost inconceivable that any mechanics alone could secure the desired result.f THE FUSION FACULTY. According to Worth, sight in the newborn is limited to fixation of a light so that all the finer qualities are the result of personal experience. The involuntary movements of the eyes of infants would show that there is no conception of binocular vision. The full development of the fusion faculty is not attained till the fifth or sixth year with the normal child. Physiological diplopia means that objects nearer or farther than the point fixed are 'According to Suter: "Refraction and Motility of the Eye," page 142. "The fovea centralis, upon which falls the image of every object attracting mental attention, does not exceed 0.4 mm. in diameter." Taking the distance of the nodal point in front of the retina to be 15 mm. Dennett, of New York, has shown by theorem of similar triangles, that, at n distance of one-half meter, an object to be discerned with normal acuity cannot exceed 13.5+ mm. in diameter. fSanford: "Experimental Psychology," page 106. 10 STEREOSCOPIC TREATMENT OF always seen double, but the adult has so far succeeded in ignoring this, that it is sometimes difficult to make him realize the doubling. Fiu. 3. PHYSIOLOGICAL DIPLOPIA OF OBJECTS FABTHEB OB NEAREB THAN NIK POINT FIXKD. THERE can be little doubt that this fact plays a very important role in the child's experience, the fusing at different distances developing the idea of perspective. Omitting tlie few cases of congenital defect, strabismus, better c-illed heterotropia, if we adopt the more recent nomenclature, begins between the ages of one and four, a time during which the fusion faculty should be developing. The significance of this fact in the treatment of this condition has been HETEROPHOEIA AND HETEROTROPIA. 11 so ably presented by Worth that the reader is referred to his classic treatise on Squint. The argument is here introduced to emphasize the fact that the third essential to binocular single vision is the psychic one of the fusion faculty. Without such an overruling guid- ance the necessarily exact coordination is incon- ceivable. A discussion of the academic question of the existence of a fusion center is not essential to our purpose, and those interested are referred to Savage, "Ophthalmic Myology, " and "Oph- thalmo-neuro-myology " ; Duane, "The Extra Ocular Muscles," in Posey & Spiller's "Eye and Nervous System." The frequent clinical experience, that loss of sight of one eye is frequently followed by diver- gence, is an unanswerable argument for the im- portance of the fusion faculty in keeping eyes straight and it is the purpose of this writing to show that it plays quite as important a part in the production and the cure of those tendencies to turn, grouped under the name heterophoria. Even Stevens, who did such pioneer work in calling attention to heterophoria as a cause of asthenopia and reflex nervous disturbances, has devoted himself entirely to the physical side of the subject. 12 STEREOSCOPIC TREATMENT OF CHAPTER II. ORTHOPHORIA. HETEROPHORIA. STEVENS* PHORO- METER. SAVAGE'S MONOCULAR PHOROMKTKK. -WELLS' HANDY PHOROMETER. PHKN n< i WILLIAMS' PRISOMETER. SCREEN TEST. i> TION. CAUSES OF HETEROPHORIA. SYMPTOM > OF HETEROPHORIA. ORTHOPHORIA right tending is the condition where both eyes tend to look at the same point at all distances. Those who believe in the
  • turbing influence of kataphoria and anaphoria would dissent from calling this a condition of perfect muscle balance. While orthophoria necessitates normal orbits, proper strength/ in- sertion and nerve supply of muscles, it is also influenced by other factors. Sight requires ac- commodation for all distances from ten inches to infinity, and fixation of the two e/es upon this spot. This is a most beautiful example of coor- dination, but is easily disturbed by an abnor- mality of accommodation, which may be in the ciliary muscle itself, or in a refractive error which necessitates abnormal accommodation for its correction. It therefore follows that muscle tests should be made with the patient wearing his correcting HETEROPHOEIA AND HETEROTROPIA. 13 glasses, and also without, so that the influence of the refractive error may be determined. As absolute perfection is not to be expected, it would be advisable to adopt a minimum error which might still allow the classification orthophoria. HETEROPHOEIA cross or wrong tending is the condition of most of the human family if sufficiently careful tests are made. It would, therefore, be desirable to adopt some standard which recognizes a minimum of error to warrant the term heterophoria. Only the principal forms, esophoria, tendency in; exophoria, tendency out, and hyperphoria, tendency of one above the other, will be here considered. Cyclophoria, a twisting tendency; anaphoria, a tendency of both eyes above the normal level; kataphoria, a tendency of both eyes below the normal level, are conditions which the writer does not feel qualified to dis- cuss, much less to treat stereoscopically. METHODS OF TESTING. Stevens' phorometer is probably most univer- sally used. Savage objects to this method be- cause both images are artificially displaced. The Savage monocular phorometer consists of a rotary prism and a displacing prism before 14 STEREOSCOPIC TREATMENT OF the same eye. This, he says, prevents the eye which is in the primary position from partici- pating. The same result is obtained with the Wells' handy phorometer, which consists of a si i mit- ten-diopter prism and a weighted disc. FIG. 4. WELLS' HANDY PHOROMETEB. When the prism is tilted till the double images are horizontal or vortical the index on the disc indicates the amount and kind of heterophoria. This instrument is not intended to measure frac- tions of a prism diopter. The Maddox rod is a very accurate test. A test which diagnoses and measures the error at HETEEOPHOKIA AND HETEEOTEOPIA. 15 the same time is one devised by Charles F. Prentice, of New York, in 1890. It is based on the principle that a prism of 1 A causes a devia- tion of 1 cm. at 1 m., 5 cm. at 5 m., etc. It is, therefore, constructed for any distance, 5 or 6 m.* o o o o o o o o o o FIG. 5. PRENTICE PRISMOMETEB AND PHOROMETER. The Wells apparatus, which has been in use since 1891, is copied from Prentice and consists of lights 1 cm. diameter, 5 cm. between centers, on the wall 5 m. from the patient. * Prentice: "Ophthalmic Lenses" Shows that for exact tangent measurement of prism diopters, a 6 m. distance is essential. 1l'> STKKKOSCOPIC TIII.A I M I.NT or Vertical lights are green horizontal lights red. Patient is armed with red ulass In-fore one eye of sufficient color to obscure the green. green glass before the other eye of sutlicient depth of color to obscure the red. If red pi. be before right ami irreeii before left, right eye will sec horizontal red lights ami left eye verti- cal green lights. Tf orthophoria exists a perfect cross will be seen as if both the colors were seen by one eye. If exophoria, green lights will be displaced to the right, one spot for ea< It />//>/>/ i>t<'r. If only two red lights are seen to the right of the green, patient has 5 A of exophoria. Red line seen on a level with the first green spot below the center indicates 1 A right hyperphoria. \Vil- Mains, of Boston, has improved this test ly >uh stituting luminous figures for the round spots. the arrangement being such that the tendency to "horizontalize" or "vci-limlhr" is entirely eliminated. The theoretical superiority of this test is that it ohviates the necessity of distorting. blurring or displacing either retinal image.* By all of these tests <|iiite similar results *The writer has fallen into the habit of calliiii: this tin 1 chromatic test. It mi^'lit be called the "red and green," or perhaps the Prentice -Williams', unless someone has prior claim. HETEROPHORIA AND HETEKOTROPIA. 17 should be obtained, but in one's record the par- ticular tests employed should be indicated. The cover or screen test is quite generally employed, and consists in alternately covering each eye with a card, while the patient fixes a distant light. The eye behind the card deviates if orthophoria does not exist, and recovers its fixation when the other eye is covered. Prisms held before one eye until all motion stops, meas- ure the amount of the error. This method the writer learned from Suffa, of Boston, in 1895. This cover test differs from all of the others in that it is a strictly monocular test, and the influence of the fusion faculty is entirely elimi- nated. It is argued by the advocates of this method that it most truly reveals the real tendency. In cases of high degree of heterophoria, or occasional heterotropia, the movement of each eye behind the screen should be observed- noting which recovers its fixation the more quickly on removing the screen. Obviously this is the favorite eye, and the one that lags will be the one that is suppressed in the tests of fusion to be given later. 18 STEREOSCOPIC TREATMENT OF DUCTION. Whether the case be one of orthophoria or heterophoria it is important to know tl it- strength of the recti muscles, as many ortho- phoric patients have such weak muscles that they are unable to do continuous work without asthenopia or nervous disturbance. Normal accommodation means that each eye shall be able to focus an object as near as 8 to 10 cm. If the pupillary distance be 60 mm., convergence to this distance requires 60 A . If the average reading distance be taken as 30 cm., 20 A would be used. As the comfortable maintenance of accommo- dation at 30 cm. requires an ability to accommo- date at 10 cm., so the convergence faculty must be much greater than the amount habitually used. Cross,* of Worcester, Mass., ''believes that if the fusion range is not at least twenty per cent, in excess, there are apt to be more or less asthenopic symptoms. ' ' Landoltf says, "We have tried to determine the quota of convergence, and our experience 'Personal communication. f'Norris and Oliver System of Eye Diseases," Vol. IV, p. 133. HETEROPHORIA AND HETEEOTKOPIA. 19 seems to demonstrate that this reserve amount ought to be about twice as great as the conver- gence required by the work." Evidently the amount of reserve convergence necessary varies with the hours of application. It is certainly conservative to say that the actual power should be double that ordinarily used. Duction is measured by the power to over- come prisms and maintain single vision. Loose prisms from the trial case may be used until the limit is reached, but the rotary prism is more convenient. Howe* has maintained that the accurate meas- urement of duction requires the use of prisms in reverse direction, beginning with one beyond the patient's ability to overcome, and working down to weaker, until the strongest which can be fused is found. This method was adopted by the A. M. A., 1907, as the standard, which, it would be understood, had been employed when cases were reported to the society. The writer pleads guilty to having continued the old way, but admits that repeated trials often give quite different results, showing increasing power. "'The Muscles of the Eye." 20 STEREOSCOPIC TREATMENT OF Although there is no general agreement among the writers on this subject, it is probably conservative to consider 24 A as normal duction for the interni, 8 A for the extern!. CAUSES OF HETEROPHOHI A. There are five generally accepted canst-- ..r heterophoria : First. The malformation of cranium ami orbits. Second. Abnormal power, weakness or strength of one or more muscles. Third. Tendons too long or too short. Fourth. Insertions of tendons too far t'arwanl or back. Fifth. Errors of refraction. But it is the author's belief that a sixth c;m-e. very generally overlooked, is an incomplete development of the fusion faculty. This 1 Following the model of the late Dr. Richard Derby, adjustable object carriers were provided, 'with somewhat elaborate mechanism for verti- cal adjustment and an endless screw for ap- proximating and separating them. This was essential to secure a gradual and smooth mo\< ment, otherwise the eyes ceased to follow and fuse the two objects. KM;. ('.. PHOBO-OTTOMKTEB S i'i . After using this arrangement SOUK- time, it was discovered that patients who foutfd s disturbed if the spheres were separated l>\ turn- ing the screw for pupillary adjustment, and that HETEROPHORIA AND HETEROTROPIA. 29 a much greater degree of prism could in this way be fused. The Wells stereoscopic attachment to the phoro-optometer illustrated in ' ' Meyrowitz Bul- letin," 1903, shows the movable object carriers, but in the author's instrument they soon became fixed at 6 cm. apart. It was later discovered that if one were a little FIG. 7. NEW PHORO-OPTOMETER STEREOSCOPE SHOWING SIMPLE CLIP TO HOLD CARDS. 30 STEREOSCOPIC TREATMENT OF careless in fixing the objects in the carriers, a slight tilting or vertical error interfered with fusing, so the object carriers fell into disuse and stereoscopic cards were used instead. The im- proved form is, therefore, simply the addition to the phoro-optometer of a clip to hold the cards. In 1904 the Wells selection of stereoscopic cards was published. This was a selection of the most useful from those previously brought out by Kroll, Dahlfeld, Hale and Javal. Only a few new cards were added by the writer. A second edition has now become necessary. The new edition includes some very ingenious tests in fusing complementary colors by Dr. George A. Shepard, of New York, and a new set for amplitude training by the author. The lettering and grading have been somewhat changed. To guard against any misunderstanding the reader should bear in mind that in the instruc- tions which follow, the letters and figures refer to the second edition, which is being published at the same time with this book. DECENTERING SPHERES TO SECURE PRISM. The application of the principle of decenter- ing of the spheres for the purpose of introduc- HETEROPHORIA AND HETEROTROPIA. 31 ing extra prismatic effect, as applied to fusion training, is believed to be original with Javal,* but it has been greatly extended by the author, and its superiority over any other method known to him justifies a somewhat detailed de- scription. With o. u. +10., cards at 10 cm. are in focus. If the separation corresponds to that of the pupillary distance of the patient's eyes, no pris- matic element is exhibited. If decentered 1 mm., 1 A approximately is produced. Thus +10. spheres make the calculation of the prism ex- tremely simple. If the spheres are decentered out 5 mm., we have put before the patient 5 A of prism base out, just as truly as tho a 5 A prism were inserted in the clip. If the spheres are decentered in 5 mm., 5 A base in is obtained. As the pupillary adjustment may be varied from 50 to 75 mm., it follows that 10 A or more may be utilized by this simple principle of decentration. *"Manuel du Strabisme," p. 115. 32 STEREOSCOPIC TREATMENT OP CHAPTER IV. STEREOSCOPIC TREATMENT OF EXOPHORIA. AU- THOR *S CARD FOR MEASUREMENT OF STEREO- SCOPIC HETEROPHORIA. AMPLITUDE OF FU- SION. RECOVERY EXERCISES. HOME IXI.K CISES. THE SUPPRESSED EYE. CONTROLLED READING. AUTHOR'S DEVICE. NUMBER OF CASES TREATED AND RESULTS. STEREOSCOPIC TREATMENT OF EXOPHORIA. Let us suppose a case of exophoria of 10 A dis- tance, adduction subnormal, greater conver- gence faculty needed. With o. u. +10. in the clips, centered to correspond to patient's pupil- lary distance, card marked BI is put in clip, and 876543 FIG. 8. BL the patient is asked over which dot he sees the arrow. He will probably answer "five" or "between five and six." If five, this means that he has selected the number five spot with which HETEROPHORTA AND HETEROTROPIA. 33 FIG. 9. SHOWING THE LINES OF SIGHT WHEN THE PATIENT SEES THE ARROW OVEB 5'. 34 STEREOSCOPIC TREATMENT OF to fuse the arrow spot, therefore 5 cm. is the patient's easiest fusion distance with o. u. +10. Glasses correcting the refractive error should, of course, be worn and if there is much pres- byopia, the o. u. + 10. should be made enouirh stronger to correct it. This will slightly increase the prismatic effect of the decentering. Eyes are closed and the two rotary prisms swung into position to give o. u. 5 A base out. Patient opens his eyes and again states position of arrow. If over six the amount of prism which makes six centimeters the easiest fusion distance has been found. If not correct one or two trials will secure it. Should arrow be seen between six and seven, less than o. u. 5 A is required ; should it be seen between five and six, more than o. u. 5 A is needed. As all the cards, except series H. B and T, are 6 cm. between centers, the stereoscope is now approximately suited to this particular patient, and we, therefore, proceed to test his fusion faculty. Unless the case be one of anisome- tropia or amblyopia, it is well to begin with series F. Patient should see the vertical lino passing through the dot. If the line, which is seen by the left eye, is too far to the right; that is, HETEROPHORIA AND HETEROTROPIA. 35 heteronomous diplopia, the prism base out should be reduced till the direct alignment is secured. If the line be to the left of the dot, it is evident that the reverse is indicated. Fi g o o d (Javal KI3) By means of the card Bs the exact prism needed may be determined. Obviously it is the amount with which the patient sees the lines intersect at six, but the cruder method with B x is preferable in the beginning. B 3 is designed especially for the accurate measurement of stereoscopic hyperphoria, which is often quite different from that shown by other tests. The divisions of the red vertical line are 5 mm. apart. If the black horizontal line is seen to cross the red vertical line at H, 5 A right hyperphoria is exhibited. Hyper- 36 STEREOSCOPIC TREATMENT OF phoria may interfere with fusion. It is then necessary to correct all or part of it with a vertical prism in the clip. BJ IWellj) Fic. 11. Patient's eyes are closed (unless other \\ i si- stated, it is to be assumed that patient's eyes are always closed before each change) and sue ceeding numbers of F used in numerical order. It should be noted if either eye fails to see its respective lines and dots, and if suppression occur, whether it be always *of the same eye or of alternate, right and left. Let us suppose that, beginning with F 4 , the left eye fails to the line or dots belonging to the left picture, altho the letters are correctly read. The case should be recorded : "Stereoscope + 10. = 5 cm., o Pr. o. u. 5 A B out = 6 cm. Suppresses Left F 4 , 5, e, 7, s." HETEROPHOEIA AND HETEROTROPIA. 37 This test might have been made with Cg or series G, but it has been found that series F fur- nishes quicker and more reliable information. Series E is devoted to perspective. If with Ei, the antero-posterior relation of the dots is correctly stated, the subsequent numbers are tried in order. If Es is not cor- rectly seen, to the record is added "E, o. K. to 4"or"FailsE 5 ." AMPLITUDE OF FUSION. CT is now put in place, and as the N 's are just six centimeters between centers, the two N's are perfectly fused and the patient reads " ONE." ON NE (Wells) FIG. 12. C7. Now while the patient watches the fused im- age, the P. D. of the spheres is increased by gradually turning the screw to the limit (75 mm. 38 STEREOSCOPIC TREATMENT OF P. D.). Eyes are then closed and P. D. of spheres is reduced to minimum (55 mm.). 5 A more, making 20 A in all, is now turned up in each prism. Patient will fuse this easily but let us note just what has been accomplished. Assume P. D. = 60 mm., then he has fused 20 A less 5 A = 15 A . As 10 A was required to brinir the arrow over six on the BI card, 15 A less 10 A = 5 A = effort put forth. This process is repent* !. adding from 5 A to 10 A each time till the ",ONE" breaks apart before the spheres are fully sepa- rated. If this occur, using o. u. Pr. 25 A . wlien spheres show 65 A P. D., record should road. "amplitude 'ONE' or C 7 55V Much can be learned by watching the patient'- eyes over the top of the plioro-optometer. Usually they both converge equally, but o< sionally one eye will participate but little. ;niMI EXERCISING. tion of natural scenery, and is constantly able to verify his binocular perception by a glance at the dots. It is advisable to insist upon good photo- graphs properly mounted. The H. C. White Company, of Bennington, Vt., offer a fine selec- tion of views from all parts of the world. HETEROPHORIA AND HETEROTROPIA. 47 Cross, of Worcester, Mass., has devised a cylinder with 13 facets, on which he has pasted the 13 cards of series H. This is mounted on the Holmes stereoscope, arranged with a ratchet so that the patient can turn up one after the other of the cards, progressing in either direction. If, as some think, it is wiser to have a period of relaxation between the repeated efforts of con- vergence, Cross suggests that patient's eyes may be closed while the cylinder is being revolved. CONTROLLED READING. Javal illustrates the control device of Bull, which is an aff air somewhat resembling a stereo- scope with an opaque bar midway between the eyes and a card placed in the clips. To over- come the possibility of a patient reading alter- nately with right and left, Javal constructed his "grill," a little table with five vertical bars. This is placed, standing on four legs, on the page to be read. After experimenting with various appliances the author devised a control which enables the principle to be applied to all of the patient's reading, writing and sewing. A description and illustration of this was published in Meyrowitz Bulletin, January, 1905. 48 STEREOSCOPIC TREATMENT OF It consists of an ordinary head band, either leather, silk or the metal spring, but in place of the mirror, an aluminum band is attached by the ball and socket joint. This admits of con- FIG. 17. AUTHOR'S CONTROL DKVICE. siderable adjustment, which can be supple- mented by bending the aluminum. The band is blackened to avoid reflections, and is placed half way between the face and the page. If either eye be suppressed a black band is seen across HETEEOPHOEIA AND HETEROTROPIA. 49 the page. This is shown to the patient by alter- nately covering the eyes. If patient does not occupy a conspicuous place, this control can be FIG. 18. TBIPLE CONTROL DEVICE. used for practically all near work, and this is insisted upon. At first there will be some com- plaint, but most patients soon come to appreciate 50 STEREOSCOPIC TREATMENT OF the steadying effect and the ability to read with more comfort. The latest model, Fig. 18, has three control bands and resembles an inverted trident. The central band is 10 mm. wide, the lateral ones 7. and the spaces 13 mm. If this be held not more than 15 cm. in front of the eyes, the field > ovei lap sufficiently to allow of comfortable reading, but three times in each line the control principle- is brought into play. With a pupillary distance of 60 mm., the con- trol at 15 cm. and the reading held at '.'>~> cm. (14 inches), the overlapping is about 6 mm. Obviously this increases with the distance. This triple control necessitates more exact adjustment than the single band, and may not be practicable for all near uses, but for quiet reading, it prevents suppression as effectually as JavaPs "grill." The author is familiar with Gould's theory of dextro and sinistro-ocularity,* but feds ohli.uv.l to differ from the opinion that any marked sup pression of either eye is physiological. l"n- doubtedly many people who habitually suppress 'Ophthalmology, Oct., 1904 HETEROPHOEIA AND HETEROTROPIA. 51 one eye may not suffer any annoyance from this condition. The same may be said of errors of refraction, but does anyone for that reason con- sider astigmia physiological! The writer main- tains that the habitual use of the two eyes binocularly, with a minimum of suppression of either, is as ideal as is the emmetropic eye to uniocular vision. Therefore, every known means is utilized to overcome this suppression. If marked, it is ad- missible to atropinize the favorite eye. One of the less powerful cycloplegics is generally suffi- cient. A thin film of soap may be smeared on the stereoscopic lens corresponding to the favorite eye. The whole object is to force the patient's use of the suppressed eye, by handi- capping the favorite one. NUMBER OF CASES TREATED AND RESULTS. In advocating a new method of treatment, it is realized that something must be said about results, but it is a somewhat difficult task to report accurately concerning therapeutic ac- complishments. Probably nine-tenths of those treated have 52 STEREOSCOPIC TREATMENT OF been exophorics, so that of this class there have been a sufficient number to justify one in draw- ing some conclusions. Tn the last five years 330 cases of this class have been treated by tlio methods explained above. Of these about sixty per cent, have gained a good convergence faculty varying from 60 A to 90 A , and the symp- toms have been relieved. Some of these have become orthophoric by the various phorometer tests. Others still exhibit some exoplioria, Imt much less than before. These are all classed as " cured." Fifteen per cent, have developed equally good convergence, but symptoms are not relieved. Evidently symptoms were not caused by insufficiency. Fifteen per cent, more have attained to 30 A or 40 A and secured partial relief. About ten per cent, must ln Classed as fail- ures. No improvement in muscle power could be secured. For some reason they did not respond. These last were not given a full course of treatment. If marked improvement is. not evi- dent after five or six visits, the treatment is stopped. Undoubtedly this list includes some cases of nervous instability, which a keener diagnosti- cian would have referred to the neurologist. There have been some relapses, but the great HETEROPHORIA AND HETEROTROPIA. 53 majority of the "cured" cases have retained sufficient power for all practical purposes. Pa- tients are admonisjied to test themselves from time to time with the stereoscope and cards, and if they notice any loss of power, to renew the home exercises. 54 SI KIM.OSCOPIC TREATMENT Ob" CHAPTER V. STEREOSCOPIC TREATMENT OF ESni'll' HMA. MA"\ AN EXPRESSION OF CONYKKi ii.N < I. INSl'lll CIENCY. FUSION TRAINING SAME AS FOR 1 PHORIA. AMPLITUDE TRAINING Till. IIKVI OR MAY BE THE SAME AS FOR EXOPHORIA. ESOPHORIA. The proper treatment of esophoria nee tates a proper estimation of all the factors con- cerned. One is not justified in concluding that the convergence faculty is too strong. 1 phoria at distance is often associated with exo- phoria at near. In these cases duction will be found quite limited. Paradoxical as it may seem, the writiT is convinced that esophoria at a distance is not infrequently an expression of convergence insufficiency. Just how this is brought about he has no very definite opinion, but as the conver- gence function is the one most directly under the control of the will, it is conceivable that it might be exercised "not wisely, but too well" in a vain effort to overcome some annoying exophoria or hyperphoria. HETEROPHORIA AND HETEROTROPIA. 55 Esophoria, dependent on latent hyperopia, is quite common, and there is a consensus of opin- ion as to what this association implies. The constant need of innervation of the ciliary for distance, as well as near, in some way causes an overstimulus of the associated convergence the coordination is disturbed. The full cor- rection of the whole refractive error under atropine is, therefore, the first requirement and usually gives relief, but many of these cases show no reduction of the esophoria, the symp- toms persist and the blurring of distant objects is quite annoying. For these cases and those not hyperopic, what shall be done? The use of prisms base out frequently "begets the calami- tous necessity of keeping on." With each increase of prism more esophoria develops, till one may be forced to do a tenotomy or advance- ment to give his patient relief. The stereoscopic treatment consists first of a thorough testing of the fusion faculty, and if any defect be found, the use of controlled read- ing (explained in Ghap. IV) and the stereo- scopic charts which cultivate a refinement of fusion, like D, E, F, G. To this point the treat- ment may be identical with that given for exophoria. 56 STEREOSCOPIC TREATMENT OP In using the phoro-optometer stereoscope, patient should learn to fuse with prism base in, if we are to secure a greater divergence power. The same o. u. +10. are used in the frame, and card Bi determines the easiest fusion distance by position of arrow. Let us suppose it be seen over three, this means that the two discs 3 cm. apart are the easiest fusion distance. Rotary prisms 15 A each base out ought theo- retically to bring the arrow over 6. C? ON NE is then introduced and the spheres approxi- mated so as to reduce the base out of the rotary prisms. When limit has been reached, patient's eyes are closed and the lenses separated as far as possible, and the base out of the rotaries reduced 5 A , leaving 10 A each. If the patient's pupillary distance be 60 mm. and the phoro-optometer show 70 mm. P. D., 15 A each base out will be exhibited in this wide open position and this will be as easily fused as at first. Now if the spheres be approximated while the patient holds the letters fused, when P. D. 60 has been reached, the prismatic element of the decentering has been eliminated, and the amount as shown by the revolving prisms, 10 A each, is the total. If the approximation be con- tinued to 50 P. D., then the 5 A each base in HETEEOPHOEIA AND HETEROTROPIA. 57 produced by the decentering reduces the base out of the revolving prisms, and the patient has diverged from his first position and maintained fusion with o. u. 5 A base out. Eyes are now closed again and the spheres separated as far as possible. Rotary prisms are now reduced 5 A each, so that the reading which was before 10^ is now 5 A . Patient opens his eyes and if he is able to fuse the ON NE, lenses are approximated as before. This process is repeated with smaller changes in amount of rotary prisms as it becomes evident that pa- tient's limit is becoming reached. As was said before, the home use of the cards as far as series G is the same with all forms of heterophoria, because with all of these cards the distance between centers is 6 cm., and their use is for the cultivation of a refinement of the fusion faculty. For amplitude training it is evident that the progression in the use of series H and series I must be reverse of that for exophoria; that is, if patient sees the arrow over 4 with Bi card, he should commence with m or 14 and work up to higher numbers, 5, 6, 7, etc. In many cases where there has been pres- ent esophoria for distance and exophoria for near the convergence duction has been found so 58 STEREOSCOPIC TREATMENT OF poorly developed that the writer has treated the case the same as for exophoria, both with the phoro-optometer stereoscope and the home- work for cultivating amplitude. Increased convergence has relieved the symp- toms and has not increased the esophoria. In some instances orthophoria has been restore* I. It is experiences like these which have forced the conclusion that there exists a pseudo- esophoria, which should be interpreted as an insufficiency of convergence and not excess. HETEROPHORIA AND HETEROTROPIA. 59 CHAPTER VI. TREATMENT OF H YPERPHORIA. STEREOSCOPIC TREATMENT NOT PRACTICABLE. PRISM DUC- TION TREATMENT. AUTHOR '& CARDS FOR RIGHT AND LEFT H YPERPHORIA. HYPERPHORIA. In a few cases stereoscopic treatment has been attempted with revolving prisms. The hyper- phoria, as indicated by cards B 2 and B 3 , is cor- rected by vertical prism. The ON NE card is in- troduced, and while the patient holds the image fused the prism correcting hyperphoria is re- duced to zero, and as much reverse prism used as the patient will endure without losing the image. This is a kind of stereoscopic duction and can be repeated as many times as thought desirable. The results have not been sufficiently good to warrant its continuance. In 1908 the writer devised two new series which were published as a supplement to the first edition of stereoscopic charts. These were designed for the treatment of hyperphoria. The characters ON NE were made of block letters 8 mm. square, horizontal separation being 60 STEREOSCOPIC TREATMENT OF 60 mm. in all. Each set consists of five cards. For right hyperphoria the right object NE is lowered 2, 4, 6, 8, 10 mm., corresponding t<> right hyperphoria of 2 A , 4 A , 6 A , 8 A , 10 A . if me ured at 10 cm. , AI ii. > - R Hypophou 2* ON (WdU) FIG. 19. DISCONTINUED SERIES. For left hyperphoria the left object ON is lowered 2, 4, 6, 8, 10 mm., corresponding to left J IO A. uc. - L HypcfphoiU 10* NE ON (WdU) FIG. 20. DISCONTINUED SKUII B, HETEROPHOEIA AND HETEROTROPIA. 61 hyperphoria of 2 A , 4 A , 6 A , 8 A , 10 A , if measured at 10 cm. The writer's idea was that if a patient with right hyperphoria of 8 A could fuse Is most easily, he should be able to progress to IG, 14, 12, and thence to the ordinary cards with both sides horizontal. The results, however, were not satisfactory even when hyperphoria meas- ured with 64 in stereoscope at 10 cm. corre- sponded to hyperphoria measured at 5 M. Since no one with whom the writer has com- municated has had better results with series I and J, they have been omitted from the present edition. A stereoscope might be constructed in which the spheres could be decentered vertically and the same principle applied as for training con- vergence and divergence, but of the result the writer is not particularly sanguine. Hyperphoria frequently disappears as the convergence power increases, and if it remains in sufficient amount to give rise to symptoms, it is the author's practice to correct it with a prism, or if of high degree by tenotomy or ad- vancement. 62 STEREOSCOPIC TREATMENT OF CHAPTER VII. KEOSCOPIC TREATMENT OF HETEROTROPIA. OF CONCOMITANT ESOTROPIA. THE AMBLYOSCOl'l . AUTHOR'S DEVIOMETER. THI: I-KKCENTAGE OF CURES. THE TIME FOR OPERATION. TREAT- MENT OF ALTERNATING ESOTROPIA. TR1 MENT OF EXOTROPIA. ESOTROPIA. Ever since Worth's first publication in ilu- Lancet, May 11, 1901, the writer has been a Con- scientious follower of his methods. His suggea tion of atropinizing or bandaging the fixing eye for months is certainly of great value, and although it had been previously practiced by Landolt and Javal, Worth did well in emphasiz- ing it so forcibly. A certain number of cases of concomitant esotropia can be cured by this method ami tin- use of the amblyoscope, but this latter instru- ment has been rather disappointing. Then- a IT definite drawbacks to its practicability. In the first place, one cannot see tin- child's eyes and is, therefore, forced to depend on his statement as to what he sees. The imagination of the child HETEROPHORIA AND HETEROTROPIA. 63 is very vivid and no one who has tried to carry out this treatment can have failed to be at his "wit's end" many times to know just what was taking place. Then it is absolutely essential that FIG. 21. Tin: AUTHOR'S DBVIOMETEB ATTACHMENT TO THE PEMKKTER. the case be seen early and that the parent's intelligent cooperation be secured. Following Worth's suggestion the writer de- vised a deviometer attachment to the perimeter. with which it is possible to measure the an of the deviation in quite young children. A concealed switch is so arranged that the central light, which the child naturally fixes, is put out at the same instant the movable one is lighted. Thus, before he has time to change his fixation, the reflection of the movable one is noted on the cornea. A few trials suffice to make it central, and the degree of heterotropia is read off on the arc. This ability to make comparative measure- ments is an essential part of the treatment, in order to know if the error is getting les-. Tin- wearing of full correcting glass in the fixinir eye and occasional atropine in the same, with some less than full correction of refraction for suppressed eye, will usually reduce the error one-half. Little more than this can be done with a very young child. As soon as possible Worth's marble test should be used to get a crude idea of visual acuity. When the child is able to comprehend the amblyoscope, it is given with the simplest pic- HETEROPHORIA AND HETEROTROPIA. 65 tures for home use, and the phoro-optoraeter stereoscope used at the office. Fusion can often be secured with the latter in a case needing o. u. prism 30 A base out. Here we make use of Ai for left esotropia, A 2 for right esotropia. FIG. 22. Not until concrete pictures like Ci, 2, Cs can be fused need one expect much from stereo- scopic exercises. FIG. 23. 66 STKKKOSCOPIC TREATMENT OF There is very little holding power in discrete pictures, either with the stereoscope or amblvo scope, the bird out of the cage makes just as pleasing a picture as the bird /'// tlu- caire. Itut wlien the head of C-j loses an eye or an ear, one's sense of propriety is offended. The prismatic element can be reduced by de- centering, the same as in treating euphoria. and the eyes may be watched all the time over the top of the instrument to note their move- ments. In a favorable case the home >t M scope with as high as o. u. 15 A base out can In- used, the amount Iteing reduced a< condition- warrant. It is somewhat difficult to state exactly the percentage of cures that may he expected by orthoptic treatment alone. It is almost inn sible to carry out the full treatment with dis- pensary patients. Kmerson,* of Orange, X. .1.. says: "In pri- vate practice, patients of good social condition, who carry out the treatment with intelligence and perseverance, practically all .uvt well." This statement is slightly ambiguous, as it is nf tin' M- lii-iil Sncicty nf \.-\\ .Ii-r-cy." l!ll. HETEROPHORIA AND HETEROTROPIA. 67 not stated in what proportion the necessary "in- telligence and perseverance" are exhibited. Of all the private cases of esotropia seen by the writer during the last five years only twenty- five per cent, were less than six years old. Some of these moved away and were referred to col- leagues in other cities. Others gave up the treatment after a few visits. Excluding the congenital cases, nine per cent, were given the recognized orthoptic treatment, and of these nearly three-quarters were cured and developed a fair degree of binocular vision. A few cases averaging thirteen years of age responded to glasses and fusion-training meth- ods. Most of the other cases were corrected by advancement or advancement and tenotomy. Post-operative fusion training has been used in all except those lacking all fusion sense. Since only twenty-five per cent, were less than "six years old, it is evident that it is still neces- sary to emphasize the importance of beginning this treatment early. The intelligent cooperation of the family phy- sician means that he shall refer every case to his ophthalmic surgeon, whenever there is dis- covered even an oa-dxioiial squint. It is true that the wearing of glasses under two years is 68 STEREOSCOPIC TREATMENT OF attended with some difficulty, but many other expedients can be used to force the seeing with the turned eye. These may be atropine in the fixing eye and an occlusion bandage. Tin- object of this very early treatment is to preserve the turned eye from amblyopia exanopsia. ami to cultivate the fusion faculty during those years when it is developing in the normal child. This treatment should be continued as lonu MS the deviometer shows improvement. This may be months or years, but it is certainly a mistake to delay operation too long. A rudiment of fusion can often be trained into a refined faculty if the eyes are put approximately straight l>y operation. The writer considers the Worth advancement a very satisfactory method, beginning with the external rectus of the esotropic eye. The one difficult part is the introduction of the scleral suture. Instead of passing the necdlr directly toward the pupil, it is passed parallel to circumference of the cornea, beginning each one near the median line. This secures a firm hold without encroaching dangerously near the anterior chamber. This method was in vogue at Fuchs' clinic in 1905. If the convergence is not sufficient to justify tenotomy of the interims. HETEEOPHOEIA AND HETEROTROPIA. 69 it is giv r en a thorough stretching (Panas) before the sutures are tied. If the effect be insufficient the externus of the other eye should be advanced in the same manner. FIG. 24. AUTHOR'S MODIFICATION OF WORTH ADVANCEMENT. ALTERNATING ESOTROPIA. In these cases vision is usually equal in the two eyes, and there is very little refractive error. 70 STKi;i:)S( dl'K TKKATMKNT OF A cycloplegic, or even a slight blurring of either eye, causes it to converge and the other eye to ti\. Fusion faculty is usually nil, and any sort of orthoptic treatment generally of little use. Advancement of both external recti is usually required. EXOTROPIA. If occasional, stereoscopic treatment ami fusion training will usually cure the exotropia. the method is the same as for exophoria. The result is often orthophoria by phorometer. Maddox rod or chromatic test, but exophoria may be still shown by the screen test. As the normal condition of the individual is with both eyes participating, it seems appropriate to u-e a binocular test, especially the rhromatie. in which the tendency to hori/ontali/.e and verti- ealize is reduced to a minimum. This also show- the value of the fusion faculty in maintaining orthophoria. If the exotropia exists all tin- time immediate advancement of the internal rertus. followed by stereoscopic training, is indicated. HETEROPHORIA AND HETEROTROPIA. 71 CHAPTER VIII. THEORIES. PSYCHIC ELEMENT. THE CHOICE OP CARDS. SUPERABUNDANCE OF AMPLITUDE A VALUABLE RESERVE. CONCLUDING REMARKS. A highly developed fusion faculty, with good amplitude, is essential to the state called muscle balance. In correcting or relieving heteropho- ria, the first essential is the development of a refined fusion sense, if such does not exist, or in making habitual its employment in the psychic interpretation of two retinal images. The power of a muscle depends not alone on its own physical properties, such as size, nutri- tion, place of attachment, etc., but also on the strength of the nervous stimulus which excites its action. In discussing this subject in 1902 the writer made the following statement: "The rapid development of adduction which is so often obtained by this so-called 'gymnastics,' strongly suggests that the gain is not a muscle hypertrophy, but an increase in innervation, either in the responsiveness of the end organ in the muscle, or the convergence center, or both." In the educational treatment of tabes the inco- ordination is overcome by teaching the patient 72 STEREOSCOPIC TREATMENT OF to gauge his motor impulses by the eye in lieu of the normal sensory control. Repeated arti- ficial contractions of the internal rectus (the ciliary remaining relaxed) establish a habit of increased action, so that it no longer lags when the impulse to converge and accommodate is felt. The coordinating center may also be taught to 1 icttcr appreciate the advantages of binocular perspective. This is no special pleading, but is analogous to other sensations. The pianist makes his fingers educate his brain that the brain may do better work with the fingers. Tasks consciously performed are in time relegated to subconscious control. If this interpretation of muscle u\ imiastics be accepted, it is evident that the first indication is to teach the patient the fascination of true binocular fusion. Just as in the ordinary prism exercises, with the eye fi.vd on a distant point, the aversion to diplopia is an incentive to increased muscle action, so here the fused image becomes an anchor. AVith the eyes fastened on a fused image, made up of half pictures, one strongly resists an impulse which tends to pull it to pieces. The decentering of plus 10. lenses is a subtle means of insinuating such an influence. In all exercises of this sort there is a psychic HETEROPHOKIA AND HETEROTROPIA. 73 factor which should be utilized. Whether there is or is not a fusion center, there is a fusion faculty which can be cultivated, in proportion to the patient's attention and cooperation. To do this, while the phoro-optometer stereo- scope is being used, the patient should be repeatedly directed to fix his attention on the red N. To help him do this he should be told to analyze the color, to decide just what shade of red it is, or to fix his attention on the oblique line of the N. Other expedients will suggest themselves if the importance of this fixation of attention is appreciated. No distracting sounds should be tolerated ; in fact, there should be no third party in the room. The patient should also be aware that the oculist is thinking only of him, and whenever any gain, however slight, is evident, as one watches the eyes over the stereoscope, some word of commendation should be volunteered. If no such commendation should be justified, he should be encouraged by the suggestion, "Now try a little harder this time." The difference in the holding power of differ- ent cards has been mentioned. Formerly Cs of Javal was used. This consists of separate let- ters L and F, the fusion of which gives E. 74 A fter considerable experimenting the author de- vised the ON XE, the two X's printed in red, and believes this possesses the greatest holding power of, anything yet produced. In the first place the word spells ONE, and when dis- jointed the <>X \E is meaningless. More In- ters are superfluous and detract from fixation. That there is a subtle suggestion in.this, one can easily verify in the following way: After the card ON NK has been used on several occa- sions, if the prism is arranged so patient sees arrow over 6 of the card Bi, and if then ( ': i> dropped into the clip, the patient will often he confused, but will be immediately relieved if 5 A or 10 A more of prism be turned up. This shows that while conditions were exact I y right for easy fusion of Or, the instant that card ap- peared he immediately remembered what it had previously required and involuntarily con- verged his eyes more than was necessary. In convergence insufficiency we are dealing with an incoordination of convergence and ac- commodation. The nerve impulse sufficient to secure accommodation is insufficient for conver- gence. To relieve this and to restore coordina- tion, it is necessary to incite, associate and to make habitual a greater degree of convergence HETEROPHORIA AND HETEROTROPIA. 75 with a given amount of accommodation. For this reason it has always seemed to the writer that exercises which brings into play the accom- modation as well as the convergence are illogi- cal; e. ., dot exercises .or candle as used by Gould. With eyes fixed on a distant light, it is as- sumed the accommodation is zero, but this is difficult to verify. When emmetropic eyes look- ing through plus 10. lenses see clearly at the focal distance, 10 cm., we have proof that accom- modation is relaxed and it is under these con- ditions that we secure a very abnormal amount of convergence. To a certain extent the same is true of the home use of the stereoscope with additional prisms in the clips. With perhaps one-half of one's successful cases, orthophoria will be secured, with the other half the heterophoria will be reduced, but the patient will have secured such a superabund- ance of amplitude that he is able to overcome the wrong tendencies automatically without discomfort. UNIVERSITY OF CALIFORNIA LIBRARY Los Angeles This book is DUE on the last date stamped below. j Inter-library Loan | MAR 11 J969 Sii celpi '- Si p. UB. ftp* fRECl I i zc Form L9-50tn-ll,'50(2554)444