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 Heterophoria 
 
 le Memorial Lecture of the 
 phthalmologlcal Congress 1921 
 
 By 
 
 Ernest E. Maddox, M. D., F. R. C. S. Ed. 
 
 Reprinted from Volume 3, No. 1 
 
 The American Journal of Physiological Optics 
 
 Published by the Division of Ocular Interests 
 
 American Optical Company 
 
 ^l^.^ni£s 
 
 J 
 
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 -■^r n t Tirtil^j 
 
 Heterophoria 
 
 Doyne Memorial Lecture of the 
 Oxford Ophthalmological Congress 1921 
 
 By 
 Ernest E. Maddox, M. D., F. R. C. S. Ed. 
 
 Reprinted from Volume 3, No. 1 
 
 The American Journal of Physiological Optics 
 
 Published by the Division of Ocular Interests 
 
 American Optical Ckimpany 
 

 ^^^/ C.A\ Ty^tn-^ 
 
 — .— mj — 
 
 OPTOMETRY 
 LIBRARY 
 
Heterophoria 
 
 being the ." • ' . •; • 
 
 Doyne Memorial Lecture of the Oxford Ophthalmo- 
 logical Congress 1921 
 
 Ernest E. Maddox, M. D., F. R. C. S. Ed. 
 
 THE founder, and first "master" of this Congress, 
 Mr. Robert W. Doyne, was an exceptionally ardent 
 benefactor of ophthalmology. To him Oxford practically 
 owed its Eye Infirmary, and the University its diploma in 
 Ophthalmology. 
 
 The early meetings of the Congress are alive with memories 
 to many of us, of his genial presence, setting everyone at 
 ease, even including, to our admiration, those unfortunate 
 if honoured patients upon whom members of the Congress 
 were allowed to operate! 
 
 On later occasions, the scene changed, and 'pathos' 
 entered. The well-knit frame, inured to manly sports, 
 had been manifestly overworked (for he did the work of 
 two men) and we saw the evening time of life gathering 
 about him all too prematurely; illustrating how 
 
 "Swift to its close ebbs out life's little day, 
 Earth's joys grow dim, its glories pass away," 
 
 Among many other mementoes, he has left this Congress 
 behind him but not without first committing its welfare 
 to the able hands in which it has continued to prosper. 
 
 Introduction 
 
 We owe the name, and most of the classification, of 
 heterophoria (which means a 'tendency to differ'), to 
 George Stevens, of New York, whose English ancestors, 
 it is interesting to note, were ancient benefactors of Wadham 
 College, Oxford. For twenty years before his dav, hetero- 
 
 25 
 
 GoGOai 
 
AMERICAN JOURNAL OF PHYSIOLOGICAL OPTICS 
 
 j5horia Was^'ftidied under other names, such as 'insufficiency' 
 ^nd'i&t^nt doyi^t'ons,' under the presiding genius of von 
 Gtde'fe, ahd'I'nbtlce in the literature that even what we 
 now call hyperphoria was corrected by Mr. W. A. Brailey, 
 more than forty years ago. 
 
 Heterophoria is a tendency to imperfection in the oculo- 
 motor apparatus, so let us first glance at that apparatus 
 itself. To begin with, there are several things it shares in 
 common with the rest of nature, viz. ow the surface diversity 
 and beauty, and under the surface, unitv, balance, habit 
 and rhythm. 
 
 The diversity of nature is very evident, but the under- 
 lying unity is just as real. Gravitation, for instance, 
 binds the whole universe in one, while radiant energy every- 
 where fills it with light and warmth. The same laws of 
 motion which guide a schoolboy's marble, are implicitly 
 obeyed by the remotest planet. This principle of diversity 
 in unity is found in every object of nature, for the small 
 re/3ects the great. It is strikingly so in living organisms, 
 ane is particularly well seen in the eyes. The cerebral 
 hemispheres make the brain appear double, yet it is really 
 one, and the eyes are windows (also two in one) through 
 which that most deeply hidden of all the systems, the central 
 nervous system, comes to the surface to look out upon the 
 world. It is no wonder, therefore, that Hering long ago 
 described the eyes as a single organ with two limbs. This single 
 organ he called the 'Doppelauge' and located it virtually 
 behind the root of the nose. I have ventured to name it 
 the 'Binoculus' as more easily pronounced. Pictures on the 
 maculae are normally referred to the line which connects the 
 Binoculus with the point of intersection of the visual lines. 
 You may ask; "If the eyes are virtually one, why are there 
 two?" The duality of the eyes is necessary for stereoscopic 
 vision, to give us two points of view meeting in one; for a 
 wider field; for safety in the event of accident or foreign 
 body; for beauty (for could you imagine yourselves proposing 
 
 26 
 
HETEROPHORIA— MADDOX 
 
 to a Cyclopean young lady? or a lady with three eyes?), and 
 lastly for silent eloquence; for eyes can speak, and, as the 
 poet expressed it, "Soft eyes spake love to eyes which spake 
 again." Together with the lids and eyebrows, the eyes 
 express the passing emotions, as a silent lake reflects the 
 changing sky. Just as the mind is linked with the cerebral 
 cortex, so, it would seem the emotions are linked with the 
 vegetative nervous system, and the eyes are linked with 
 both, for they express both thought and emotion. Their 
 link with the vegetative system is well shewn by the gastric 
 disturbance so invariably met with in acute glaucoma; 
 and conversely, an ice-cream, as Lucien Howe mentions, 
 will often cause a brow-ache. This "reverse action" 
 has a great bearing on heterophoria, for we may sometimes 
 consider it the cause of symptoms when itself is caused by 
 visceral irritation. As regards the muscles, nerves and 
 terminal motor nuclei the eyes are two, but with respect 
 to all higher neurons they are one. 
 
 It is a most important clinical distinction that all affec- 
 tions of the final common paths are non-comitant, while 
 all those of higher structures are comitant. Hence in the 
 presence of comitancy we cannot use such expressions as 
 'weakness of the interni, of the superior recti, the obliques,' 
 or the like. It is not that such conditions are impossible, 
 but if they are present non-comitancy is present. If the 
 internal recti were weak there would be increase of the 
 defect on looking to either side; if the superior recti, there 
 would be hyperphoria on looking to one side, and the 
 opposite hyperphoria on looking to the other side, and 
 similar 'alternating hyperphoria' as we might call it, would 
 be in evidence if the superior or inferior obliques were weak. 
 Every intraorbital explanation of comitant deviatio77S must be 
 fallacious. 
 
 Divisions of Heterophoria 
 The first great division of heterophoria, therefore, is 
 
 27 
 
AMERICAN JOURNAL OF PHYSIOLOGICAL OPTICS 
 
 into what I would call 'lower' and 'higher' heterophoria, 
 according as it is non-comitant or comitant. It is clear 
 that we need two different kinds of charts, one for the 
 muscles (Chart I) and one for the reflexes (Chart II), and 
 we need to be somewhat on the alert to know which chart 
 is appropriate to a special case. I believe all reflexes act 
 through the higher neurons. No single muscle is afl^ected 
 by a reflex. 
 
 CHART I 
 
 muscue: chart 
 
 ELEVATORS 
 
 K SUP I^ecT ' i_- SUP RECT. 
 l_. <NF. OBU- R IHF OSU. 
 
 f?- EXT. KECtI _ 
 
 «-■ \NT KECT 
 
 U- SUR OBU- 
 
 U. EXT. P£CT. 
 -* 1-EV0VERTEK5 < ^. ,^^. ^^^^_ 
 
 U. iriF" RECT. 
 R- SOP. OBU- 
 
 Lower heterophoria — that is, heterophoria due to one or 
 more aflfected muscles — is, I think, very often over-looked, 
 because we are so much in the habit of confining our measure- 
 ments to the primary position where it may not show itself. 
 The four diagonal areas of the motor field are easily in- 
 vestigated by the disc of rods, the patient's head being 
 placed in the required obliquity before a large tangent 
 scale on the wall. If the disc is not held quite in a vertical 
 plane, however, the red streak appears curved, which may 
 vitiate the test. To guard against this I employ a disc 
 swung as from a gallows, which hangs truly without being 
 able to rotate about a vertical axis. I find this extremely 
 suitable for measuring the torsion of the false image, and 
 I have asked the makers of my tangent scale to let 
 the scale be fixed to the wall by a single screw at its 
 centre of gravity, to allow of its rotation by an assistant, 
 
 28 
 
HETEROPHORIA— MADDOX 
 
 CHART II 
 
 Oculomotor Reflexes 
 
 {Suggested Classification) 
 
 KINGDOM 1:0R HOME OFFICE 
 
 (To Create the Binoculus) 
 
 HORIZONTAL 
 
 1 Convergence (Eyes approximate). 
 
 2 Divergence (Eyes separate). 
 
 VERTICAL 
 
 3 Right Hypervergence (R. rises & L. falls). 
 
 4 Left Hypervergence (L. rises & R. falls). 
 
 TORSIONAL 
 
 5 Incyclovergence (Both twist in). 
 
 6 Excyclovergence (Both twist out). 
 
 a Function = Fusion e Involuntary 
 b Prevent diplopia f Motions contrary 
 c Unify the eyes g Stimulus = Desire for single vision 
 d Take account of third dimension of h More linked with the vegetative 
 space and give consciousness of dis- system 
 tance of objects i Meissner's torsion 
 
 KINGDOM 2: OR FOREIGN OFFICE 
 (To direct the Binoculus) 
 
 HORIZONTAL 
 
 7 Dextroversion (Both turn to left). 
 
 8 Levoversion (Both turn to left). 
 
 VERTICAL 
 
 9 Surversion (Both rise). 
 10 Deversion (Both sink). 
 
 TORSIONAL 
 
 11 Dextrocycloversion (Both twist to right). 
 
 12 Levocycloversion (Both twist to left). 
 
 a Function = Fixation e Mostly voluntary 
 
 b Powerless with diplopia f Motions parallel 
 
 c Direct the gaze g Stimulus = Desire for macular per- 
 
 d Take account of first and second di- ception 
 
 mensionsofspaceandgiveconscious- h Linked with labyrinths, and somatic 
 ness of direction and attitude of equilibrating system 
 objects i False torsion 
 
 29 
 
AMERICAN JOURNAL OF PHYSIOLOGICAL OPTICS 
 
 until it is parallel with the streak of light. A weak vertical 
 prism before the other eye, or clipped on to the disc of rods, 
 makes the test easier. I sometimes use a rotating wand 
 attached to the wall, or to an old Bjerrum screen, by a nail 
 through its centre. The diagnosis of paretic muscles is, of 
 course, made on the same principles as for frank paralysis. 
 I still think that, for the vertically acting muscles, the best 
 method is that outlined in my book on the Ocular Muscles^ 
 namely: to make the diagnosis from the vertical separation 
 only, and then confirm it by the torsion, leaving the hori- 
 zontal element out of account. 
 
 Let us now consider higher heterophoria. I would like to 
 draw your attention to the twelve beautiful reflexes of which 
 I believe six preserve the eyes in one, while the other six 
 make them dance hither and thither like a pair of merry 
 children hand in hand. Some of them are familiar to you, 
 others probably not. They are in six reciprocal pairs, on the 
 "give and take" principle, and they no doubt have the 
 "reciprocal innervation" discovered by Sherrington. 
 
 Hering took account of only five motions in framing his 
 theory, and modern text-books of physiology enumerate no 
 more, but in ophthalmology, others have gradually made 
 themselves evident during the last thirty years, and I think 
 now all these twelve are definitely proved, except the 
 second, in favour of which two reasons might be given, and 
 two against. I have tried to classify them into natural 
 orders, as shewn in this chart. 
 
 Another list, I ought to say, has been made by Professor 
 Savage of Nashville, a list of ten, but difi^ering from mine as 
 being on the lines of lower heterophoria instead of higher; 
 that is to say they are in terms of the muscles. The most 
 interesting division I have found of the twelve reflexes is into 
 two kingdoms or groups, one of which might be called the 
 'Home Office,' since its function is to settle the domestic 
 differences of the eyes; and the other the ^Foreign Office' 
 since all its interests are abroad. In the former the motions 
 
 30 
 
HETEROPHORIA— MADDOX 
 
 are all mutual, /. e. towards or away from each other; in the 
 latter, all parallel. These two groups never usurp each 
 other's functions, and yet work in perfect harmony. They 
 are like a white man and a black man working harmoniously 
 at two ends of one saw, and yet the white man always white, 
 and the black always black. Indeed, what Hering found 
 true of convergence and the lateral movements of the eye 
 may be extended I think to the whole of each kingdom. 
 
 The third dimension in space is the only one that interests 
 the 'Home Office,' while the 'Foreign Office' is exclusively 
 concerned with the first and second dimensions. The 
 'Home Office' effects fusion, the correction of diplopia, and 
 the formation and preservation of the binoculus. It cannot 
 direct the binoculus in the smallest degree. The 'Foreign 
 Office' alone can do that and is concerned with fixation, 
 orientation, equilibration and version. The 'Home Office' 
 acts under the stimuli of threatening diplopia of six dif- 
 ferent kinds. The 'Foreign Office' is powerless to correct 
 the smallest diplopia of any kind and acts under the stimuli 
 of volition from above, combined with a subordinate fixa- 
 tion reflex from below. Miners nystagmus is, I believe, 
 largely due to a conflict between volition and the fixation 
 reflex, since the glitter on the coal solicits the latter while a 
 blow is being voluntarily aimed at a non-glittering spot. 
 This is only by the way. I think you will find the 'Home 
 Office' is more in touch with the vegetative nervous system, 
 and the 'Foreign Office' with the somatic nervous system 
 and the labyrinths. This is a very interesting distinction 
 if true, explaining why worms, indigestion, and teething, 
 cause not parallel deviations, but squints, and I have defi- 
 nitely proved my own slight esophoria to be increased by 
 gastric irritation. 
 
 These two kingdoms may therefore be looked upon as two 
 compound reflexes, playing a duet, as it were, upon the ter- 
 minal nuclei of the twelve ocular muscles. They never 
 strike single notes, but always chords. That is to say they 
 
 31 
 
AMERICAN JOURNAL OF PHYSIOLOGICAL OPTICS 
 
 never actuate single or even pairs of muscles. Now, I have 
 no doubt, since the same chords have to be struck again 
 and again, that linkages are formed between even the oculo- 
 motor nuclei of the 3rd, 4th, and 6th nerves, to mechani- 
 calise the work, just as linkages are opened up to the spinal 
 cord for the fingers. For indeed the lower motor neurons of 
 the ocular muscles are in series with those in the anterior 
 horns of the spinal cord, just as the ciliary ganglion is in 
 series with the prevertebral ganglia. 
 
 The Reflexes 
 
 The first reflex (to take them now in detail), is an old 
 friend, viz: that for convergence^ the slackness of which causes 
 exophoria, and its excess esophoria. (I prefer the English 
 pronunciation to the Greek (esophoria) as distinguishing 
 the sound better from exophoria.) Fig. 1 shews how the 
 visual lines are approximated towards the point of fixation by- 
 accommodative convergence, aided by postural habit. This 
 is the coarse adjustment. The small bracket represents the 
 fusion reflex which effects the fine adjustment. It not only 
 makes the lines meet, but fastens them together. 
 
 You may wonder what is meant by the larger bracket. 
 It represents a fusion-reflex augmented by voluntary efi^ort. 
 The arrow above it represents directed energy from above, 
 perhaps from the angular gyrus, which Gordon Holmes has 
 shewn to be connected with visual attention. 
 
 However great the postural defect may be, if compensatory 
 hypertrophy has made the fusion reflex large enough to 
 easily overcome it, the heterophoria may be regarded rather 
 as a harmless anomaly than as a pathological symptom. 
 But the moment the work to be done is almost as great as 
 the workman, the latter begins to labour, and trouble begins. 
 The fusion reflex then borrows energy from the centrons of 
 neighbouring reflexes, and from the cerebral cortex, in the 
 form of the 'forced attention' referred to. 
 
 Now a reflex is a machine, that is to say, a labour saving 
 
 32 
 
HETEROPHORIA— MADDOX 
 
 device, far more economical than voluntary effort. Sher- 
 rington has shewn how especially untiring are the postural 
 reflexes connected with the gravity muscles and no doubt 
 
 //p /p\ 
 
 Fig. 
 
 The coarse and tine adjustments of convergence. Distance posture 
 dp. Convergence posture r p. Fusion posture/ p. 
 
 something similar could be said about those of the eyes, 
 especially of the Home Office. We have lately heard from 
 him that the katabolic waste of voluntary motion is half a 
 million times greater than of these postural reflexes. 
 
 33 
 
AMERICAN JOURNAL OF PHYSIOLOGICAL OPTICS 
 
 Whether the figure is correct or not it at least makes us 
 think. The cortex is the last part of the brain to mature, 
 and the first to fail, and its exercise is the most tiring. The 
 angular gyrus lies pretty far back, and the cerebellum has 
 so much to do with these reflexes that the frequency of 
 occipital headache in uncompensated heterophoria is not 
 surprising, especially if the ablo-ascoid muscles are also 
 "wearied. 
 
 Since convergence is the strongest and most trainable of 
 all the reflexes, its slackness (called exophoria) rarely needs 
 treatment by prisms. Its link with accommodation enables 
 us to influence it by spherical lenses, a treatment which next 
 to constitutional measures, is the best. The correction of 
 astigmatism also, and of hyperphoria, helps to preserve the 
 converging reflex from being robbedof its energy. For eso- 
 phoria we use lenses vj\\\c\\fully correct hypermetropia. For 
 exophoria, generally those which partially correct it; but 
 not always, for in neurasthenia a full correction may be best. 
 "Exophoria with hypermetropia" has always been a great 
 puzzle, but I think it due to a limited amount of nervous 
 energy, of which so large a share is needed for accommoda- 
 tion as to leave too little for convergence. For many years 
 I have treated exophoria in healthy young people by concave 
 lenses, so as to invoke even superphysiological exercise of 
 accommodation, and thus harness their abundant accom- 
 modative energy to the task of sensitising the converging 
 reflex. 
 
 The diverging reflex (No. 2) is the only one I have 
 not been able to positively prove. Exophoria from "diver- 
 gence excess" is still only a theoretical conception. It is 
 moreover almost impossible to distinguish between inhibitory 
 neurons, acting on convergence, and a positive reflex acting 
 on the external recti as its efl^ectors. However, the analogy 
 of the other reflexes disposes me to believe in the latter. 
 Indeed, I suggested, thirty-five years ago, in the Journal of 
 Anatomy and Physiology that the external recti were in- 
 
 34 
 
HETEROPHORIA— MADDOX 
 
 nervated by the sympathetic in antagonism to convergence, 
 just as the dilator pupillae antagonises the sphincter. In 
 any case, there must be some mechanism, the proper stimulus 
 of which is threatened homonymous diplopia, and which 
 when damaged by haemorrhage causes sudden convergent 
 strabismus. So I have ventured to include it in my chart, 
 with all deference to Sir George Berry's able arguments 
 otherwise. Convergence may possibly be governed by 
 vagotonic fibres if my thought of sympatheticotonic control 
 of divergence is correct. 
 
 I think all the reflexes of Kingdom I are (to borrow Sher- 
 rington's term) postural, and those of Kingdom II phasic. 
 Certainly the vergences are less powerful than the versions. 
 I have sometimes thought they are slower. The modern 
 theory that the sarcoplasm is controlled by the sympa- 
 thetic, and the sarcostyles by the voluntary motor nervous 
 system may if true have a bearing on the two main groups 
 of oculomotor reflexes. 
 
 Nos. 3 and 4 are remarkable reflexes, which I believe to 
 be of a see-saiv nature. I have chosen the name hyperver- 
 gence, not because it is the best, but to be in a series with 
 hyperphoria. If a prism is held erect before one eye to 
 test the prism vergence, that one eye rises to overcome it, I 
 believe, by one of these see-saw reflexes, in combination with 
 the surverting reflex No. 9 which simultaneously raises both 
 eyes equally, to preserve the naked eye from displacement. 
 This arrangement looks so needless and complicated and it 
 would be so much simpler for each eye to have the power of 
 monocular adjustment (Prism-duction), that for many years 
 I only mentioned these see-saw reflexes as probable in spite 
 of the skew deviation of the eyes sometimes noticed when 
 the middle peduncle of the cerebellum is damaged, until one 
 day I had a remarkable patient who later went by the name 
 of 'Old See-Saw,' for one eye rose as the other fell, in large 
 regular, slow sequence. This settled my last doubt. A 
 little consideration will shew that such an arrangement must 
 
 35 
 
AMERICAN JOURNAL OF PHYSIOLOGICAL OPTICS 
 
 be, if each of the two Kingdoms is to be true to itself. This 
 figure (Fig. 2) shews what would happen were right hyper- 
 vergence to take place by itself, while Fig. 3 illustrates the sim- 
 
 Fig. 2. To illustrate the "see-saw" motion of right hypervergence. 
 (Note immobility of Binoculus) 
 
 Fig. 3. Combined right hypervergence and (binocular) surversion. 
 (Note rise of Binoculus) 
 
 ultaneous surversion of both eyes, by reflex 9. In the first 
 figure the 'Binoculus' remains stationary; in the second it 
 is raised half as much as the right eye, so that objects appear 
 displaced upwards, through half the deviating angle of the 
 prism, and this I have proved to be the case. It will be 
 noticed that the see-saw motion alone leaves the Binoculus 
 unmoved. It is most important that the mind should be 
 sensible of every movement of the Binoculus, and since 
 Kingdom I is incapable of imparting such sensation, it defers 
 all movement of the Binoculus to Kingdom. II. Herein we 
 detect the reason for an arrangement which appears needless- 
 ly complicated. It enables each kind of reflex to mind its own 
 
 36 
 
HETEROPHORIA— MADDOX 
 
 business, and to supply correct information to lieadquarters. 
 
 The normal function of the see-saw reflexes is to preserve 
 the fixation lines in the visual plane. When we wear cylin- 
 ders with oblique non-parallel axes, the see-saws are in con- 
 stant alternating exercise as we look from side to side, since 
 the prismatic effect of the lenses is such as to cause alter- 
 nating hyperphoria. This is one of the chief reasons why 
 oblique cylinders are so ill tolerated. 
 
 Since the hyperverging reflexes are of small amplitude, 
 hyperphorics are nearly always grateful for correction by 
 prisms. They are the least trainable of all the reflexes. 
 
 The cycloverging reflexes (5 and 6) cause the vertical axes 
 of the eyeballs to mutually incline towards or away 
 from each other. They act rather more on the obliques 
 than on the recti, but so as to be thoroughly comitant 
 in their effect, which could not of course be possible were 
 they to act on the obliques only. They not only correct 
 cyclophoria but have I believe an extremely interesting part 
 to play in ordinary vision, for, if I am right, they enable the 
 retinal images of sloping lines in the median plane to fall 
 upon corresponding meridians. If I hold this penholder in 
 the median plane, but with its upper end further from me 
 than the lower, reflex 6 (excyclovergence) comes into play, 
 otherwise I should see the pen double, with images crossing, 
 while if the slope of the pen be reversed, so as to bring its 
 upper end nearer to me, reflex 5 (incyclovergence) is active. 
 
 It is well known that when two arrows are depicted diverg- 
 ing above on a stereoscopic card they appear, when fused, to 
 shoot away from the observer, but when diverging below to 
 shoot towards him. 
 
 Cyclophoria in distant vision is easily measured by the 
 glass rods as already described, or by cyclophorometers, 
 and the result is sometimes valuable in helping us to decide 
 which muscle to select for an operation. In my own eyes 
 there is slight excyclophoria when fatigued, as by a long 
 walk. In the year 1890 George Savage discovered the prev- 
 
 37 
 
AMERICAN JOURNAL OF PHYSIOLOGICAL OPTICS 
 
 alence of excyclophoria in near vision while experimenting 
 with my double prism, and seven years later George Stevens 
 published his first paper on declinations. More than sixty 
 years ago, however, a torsion of the eves in near vision was 
 greatly studied by Meissner (1858), Volkmann, Helmholtz, 
 and others, and later bv Le Conte. 
 
 I will now invite vou to make an experiment vourselves. 
 Draw an upright arrow or line on the back of your pro- 
 grammes, and hold it closer to your eyes than the near point 
 of convergence so that you see two arrows. In all proba- 
 bility they diverge above, shewing excyclotropia, since the 
 images are crossed. If now you raise the paper so as to look 
 under your eyebrows the mutual slant increases, but if you 
 lower it so as to look down as far as possible, the arrows be- 
 come parallel. This proves that in near vision there is a 
 physiological excyclophoria, except on looking down, and 
 that it gradually increases as the eyes are raised, and also, 
 it may be added, as the object of fixation is brought nearer. 
 We learn from this, what Helmholtz pointed out from Meis- 
 sner's test, that in near vision the primarv position of the 
 eyes is one in which the visual plane is depressed, and indeed, 
 we naturally cast our eyes downwards for near objects to let 
 the hands and eyes work together. 
 
 If noW' you look at the same arrow with the eves turned up 
 to the right, you may notice one arrow- rise higher than the 
 other, while with the eyes turned up and to the left, the other 
 arrow may rise. In my own case the rising arrow indicates 
 an alternating hyperphoria which points to comparative 
 inaction of the superior recti as a partial cause of the cyclo- 
 phoria, so that it may have both a "higher" and "lower" 
 element. 
 
 Before leaving the subject of cyclophoria I might mention 
 that in Professor Savage's list, the place of these cycloverging 
 reflexes is taken by what he calls "harmonious symmetrical 
 action of the obliques"; but I would suggest that harmonious 
 action of the obliques is impossible. Thev would cause 
 
 38 
 
HETEROPHORIA— MADDOX 
 
 CHART HI 
 
 Conjugate Oculomotor Nomenclature 
 
 KINGDOM I. OR HOME OFFICE 
 
 
 MOTIONS. 
 
 PHORIAS. 
 
 TROPIAS. 
 
 1 
 
 2 
 
 3 
 4 
 
 5 
 6 
 
 Convergence 
 Divergence 
 
 R. Hypervergence 
 L. Hypervergence 
 
 Incyclovergence 
 Excyclovergence 
 
 Esophoria 
 Exophoria 
 
 R. Hyperphoria 
 L. Hyperphoria 
 
 Incyclophoria 
 Excyclophoria 
 
 Esotropia 
 Exotropia 
 
 R. Hypertropia 
 L. Hypertropia 
 
 Incyclotropia 
 Excyclotropia 
 
 KINGDOM II. OR FOREIGN OFFICE 
 
 
 MOTIONS. 
 
 PHORIAS. 
 
 TROPIAS. 
 
 7 
 8 
 
 9 
 10 
 
 11 
 12 
 
 Dextroversion 
 
 Levoversion 
 
 Surversion 
 Deversion 
 
 Dextrocyclo version 
 Levocyclo version 
 
 Dextrophoria 
 Levophoria 
 
 Anaphoria 
 Kataphoria 
 
 Dextrocyclophoria 
 Levocyclophoria 
 
 Dextrotropia 
 Levotropia 
 
 Anatropia 
 Katatropia 
 
 Dextrocyclotropia 
 Levocyclotropia 
 
 Vergences are contrary motions of the eyes (mostly involuntary). 
 
 Versions are parallel motions of the eyes (mostly voluntary). 
 
 Prism-vergences are changes effected in the mutual posture ot the eyes 
 by prisms which are "overcome." 
 
 Ductions are drawings of a single eye in any direction by its muscles. 
 
 Torsion means twisting of an eye about its own fixation line = wheel- 
 motion. 
 
 Cyclovergence means mutual contrary wheel-motion of the two eyes; 
 cyclotropia the result; and cyclophoria the tendency thereto. 
 
 Declination means angular departure of the vertical axis of one eye from 
 parallelism with the median plane of the head. 
 
 Phorias are "tendencies" checked in Kingdom I. by the fusion reflex; and 
 in Kingdom II. by the desire to keep the head straight. 
 
 Tropias are "turnings," causing in Kingdom I. squint; and in Kingdom II. 
 inclinations of the head. 
 
 The prefixes sur and de are contractions for "sursum" and "deorsum" 
 (compare surmount, deject, etc.). 
 
 39 
 
AMERICAN JOURNAL OF PHYSIOLOGICAL OPTICS 
 
 "alternating hyperphoria," for on looking to the right or 
 left the elevating power of the ipsolateral obliques lessens, 
 and that of the contralateral obliques increases. At the 
 same time it is pleasant to own that his theory aimed at the 
 true thing; it only needs translating from lower or incomitant, 
 into higher or comitant heterophoria to be correct. 
 
 The first four reflexes of Kingdom II are too well-known 
 to be dilated upon. They were named "versions" by 
 Duane. I have ventured to shorten the awkward 
 prefixes 'sursum' and 'deorsum' into 'sur' and 'de.' These 
 parallel motions are both voluntary and reflex. In their 
 defects no diplopia can be elicited by the glass rod. There 
 may be a limitation of version, /. e. of parallel movements 
 of the eyes, in one direction, or there may be merely a pre- 
 ponderance of one reflex over its antagonist. I regard it as 
 a'phoria if there is no vicarious inclination of the head. If 
 the head be turned to save the weak verting reflex it is, I 
 suggest, no longer a case of phoria but of tropia. Stevens 
 made a great study of anaphoria and kataphoria (but with- 
 out making this distinction), and more recently Valk has 
 written, well and ably, on dextrophoria and levophoria, as 
 studied by Stevens' troptometer. As so many become con- 
 fused about nomenclature, I have drawn up chart No. III. 
 
 The cycloverting reflexes (11 & 12) incline the vertical 
 axes of the eyeballs parallelwise to right and left. They 
 are, I am satisfied, well proved, and even their amplitude 
 can be, to some extent, measured. They enable us to 
 judge of the erectness of objects. When we look at a 
 picture, for instance, to see if it is straight on the wall, we 
 instinctively incline our heads slightly to one side and the 
 other to put these reflexes on the *qui vive.' 
 
 It is only in this indirect way that they might be called 
 voluntary. They are also involuntary steadiers ot the eyes 
 in its other parallel movements, but they do not, as some 
 might suppose, either cause or nullify "false torsion" for that 
 
 40 
 
HETEROPHORIA— MADDOX 
 
 is already perfectly accounted for, as a simple mathematical 
 necessity, by composition of the vertical and horizontal 
 parallel movements of the eyes.* 
 
 Lucien Howe, author of the most complete textbook on 
 the Ocular Muscles, has suggested a number of other innerva- 
 tions for the oblique movements of the eyes, but as I cannot 
 discover these, I have not charted them. 
 
 Tests for Heterophoria 
 
 Let us now consider a few tests for heterophoria. That 
 which first of all led me to pay attention to muscle balance, 
 was the discovery, while experimenting with two pin holes in a 
 piece of paper, that I had a slight esophoria for distance. 
 To investigate this more fully, and at the same time find 
 out how one eye would behave if placed in the dark, I con- 
 structed this dark box nearly forty years ago, and it was 
 kindly shewn by Mr. Nettleship to the Ophthalmological 
 Society. Its aim was to utilize the blind spot to record the 
 movements of a darkened eye. I found by its use that I 
 had an exophoria of about one metre angle in near vision 
 and to my surprise a great many others had similar devia- 
 tions of varying degree, so much so, that for a time I called 
 it "physiological exophoria," a name which I have now aban- 
 doned since it might make the numerous exceptions which 
 occur, especially in young people, to be thought unphysio- 
 logical. Von Graefe's test for near vision, till then univer- 
 sally employed, consisted of a dot with a line through it, 
 
 *Professor Savage has published a theory that in the oblique movements 
 of the eyes, the vertical axes of the eye-balls are preserved in parallelism with 
 the median plane by 'harmonious non-symmetrical action' of the obliques, 
 that is to say, the right superior oblique working with the left inferior, and the 
 left superior with the right inferior. I regret my inability to endorse the 
 views of so earnest a worker, for to begin with, the vertical axes of the eye- 
 balls do become inclined to the median plane in the oblique movement of the 
 eyes as a necessary consequence of Lishing's law, just as the horizontal axes 
 become inclined to the horizontal plane in the opposite sense: and secondly 
 any such combined action of the pairs of obliques named would result in a 
 vertical squint. For example, if the right superior oblique were to act with 
 the left inferior oblique, the right eye would sink and the left rise. 
 
 41 
 
AMERICAN JOURNAL OF PHYSIOLOGICAL OPTICS 
 
 reduplicated by a prism, base down before one eye. It did 
 not seem to occur to von Graefe that the overlapping of the 
 portions of the line would suffice to maintain fusion, so that 
 his test only revealed deviations in extreme cases, and 
 led to the belief that the normal relation between conver- 
 gence and accommodation was a fixed one. I must resist 
 the temptation to describe a number of other experiments 
 with this box from which indeed I learned most of what little 
 I know about oculomotor physiology. A better way of 
 using it is to disregard the blind spot and make the two 
 points of light appear one over the other when the deviation 
 can be read off direct. Its findings were confirmed by two 
 other tests; which occurred to me all the same time, namely: 
 the double-prism and the arrow tangent-scale, both of which 
 were much used for some years until the first begat the rod- 
 test, and the second the wing-test. Perhaps the prettiest 
 appliance I have made is the twin-test, consisting ot two 
 celluloid sheets of complementary colours in apposition, and 
 so pricked through that designs appear which can be brought 
 to coincide. My near vision phorometer also in complementary 
 colours is quite good if well made, but I have not brought it 
 today, for neither method secures the accommodation quite 
 so well as the wing-test. I find in practice that, on the 
 principle of the survival of the fittest, I have gradually 
 dropped all other tests except the rods for distance, and the 
 wing for near, supplemented by the redress and the parallax 
 tests (the latter so ably advocated by Duane), and my 
 prism-verger occasionally. I think no refraction is com- 
 plete without measuring both the distant and the near pos- 
 ture. The rod-test you probably know already; I like it 
 made with very thin rods, and not too small in area. It is best 
 used in a room dark enough to avoid adventitious reflections, 
 and yet with enough light to secure accommodation. I 
 have in my own eyes esophoria of 1°, but if one eye be 
 screened I have a 3/^° only. I have found many both in far 
 and near vision have about 3^° less esophoria, or }/^° more 
 
 42 
 
HETEROPHORIA— MADDOX 
 
 exophoria, on screening. This is due to slackening of the 
 converging reflex when one eye is completely covered. In 
 the wing-test both eyes receive a natural stimulus to accom- 
 modation. I have crowded the wings close to the eyes for 
 horizontal measurements to avoid exciting the ciliary muscle, 
 for objects which are hopelessly near do not tempt accom- 
 modation. It is important to make sure that the apparatus 
 is correctly made, so that the object intended tor each eye is 
 entirely hidden from the other. I have provided the rotat- 
 ing wing-test with a means of measuring cyclophoria, both 
 by vertical and horizontal lines, using the distant pillar for 
 the first, and the wings set nearer and cross-wise for the 
 second. You will generally find a difference between the 
 two measurements, due at any rate in part to the curious 
 fact investigated by Helmholtz and others, though denied 
 by Savage, Stevens, and Le Conte, that the physiological 
 dividing line between the two lateral halves of the retina is 
 not perpendicular, but slants down and in. I have investi- 
 gated the point and I find the "Helmholtz retina" exists in 
 most eyes, but not in all. The 'wing-test' is of great service 
 in the correction of presbyopia. If the arrow trespass ever 
 so little on the esophoric side, we may safely increase our 
 correction, while an unusual degree of exophoria will make 
 us careful to keep it as weak as we can without loss, though of 
 course other considerations come in as well. The most 
 important minute of a refractive consultation is that in 
 which we deliberate what reading lenses to order. 
 
 The *wing-test' can also save us sometimes from over-cor- 
 rection of hyperphoria. We may, for example, find 2° for 
 distance and about 1° in near vision. For hospital use, my 
 rotating pattern is rather fragile, and I have for many months 
 tried to puzzle out an instrument free from all movements, 
 and therefore stronger. I have at last succeeded. One 
 fixed chart now measures the horizontal vertical, and tor- 
 sional elements all "in one go." After the horizontal balance 
 has been measured, the arrow should be set at an angle that 
 
 43 
 
AMERICAN JOURNAL OF PHYSIOLOGICAL OPTICS 
 
 makes it appear horizontal to the patient. Then we can 
 read off the hyperphoria and the cyclophoria. 
 
 Treatment of Heterophoria 
 
 The treatment of heterophoria becomes a simple matter 
 as soon as we thoroughly understand the nature of a case. 
 Each needs taking on its own merits. I need only touch on 
 some elementary principles. 
 
 1 Discover the cause and remove it if possible. 
 
 2 Correct any error of refraction with perhaps a little 
 decentering of the lenses in the direction of relief. At the 
 same time treat the constitution with any necessary advice 
 as to regimen and the use of the eyes. If symptoms entirely 
 disappear, no more need be done, even if the heterophoria 
 remain. It will almost certainly be less in time, since every 
 organism tends to "come to itself" when freed from adverse 
 influences. 
 
 3 If lateral deviations are complicated by hyperphoria 
 correct the vertical deviation first and the lateral will very 
 likely correct itself. 
 
 4 If after the above treatment some symptoms still con- 
 tinue, train the weak reflex or the weak muscle as the case 
 may be. Training is chiefly indicated in young people. 
 It is only suitable for older ones when they are possessed of 
 sufficient vigour. In neurotic or neurasthenic cases it should 
 not be commenced until the nervous system, both ocular and 
 bodily, has been strengthened, and should be commenced 
 during a holiday or bracing change. Undue recession of the 
 convergence near point (or sub-convergence as I like to call 
 it) can be trained by drawing an arrow on a piece of paper and 
 approaching it to the eyes again and again while endeav- 
 ouring to keep it single. Reber's lateral version exercises 
 may help somewhat, in the same way that rowing helps 
 writers' cramp, by bringing fresh blood to the structures 
 concerned without actual exercise of the weakened neurons. 
 Prism exercises come next. I often give young people a 
 
 44 
 
HETEROPHORIA— MADDOX 
 
 second pair of spectacles resembling those they wear, but 
 with adverse prisms incorporated, and bid them wear these 
 training spectacles at certain favourable hours of the day. 
 As an alternative to this, one or two "grab" prisms can be 
 slipped on to the spectacles in ordinary wear. Whenever 
 the prisms are more easily overcome in near than 
 in distant vision they can begin by looking at a point on the 
 wall close up to it and then receding backwards to the other 
 end of the room repeating this again and again early in the 
 morning or after breakfast or rather before the eyes are tired. 
 When glasses are not worn I order prisms set in circular rims, 
 so that as the reflex is strengthened, the base-apex lines can 
 be made to lie at greater and greater angles to each other by 
 rotating the prisms in the frame. Lastly, the most powerful 
 training of all is obtained by the simultaneous rotation of 
 two prisms as in my prism-verger, the object being a disc of 
 ivory or white paper in the centre of a Bjerrum screen. My 
 verging prisms {i.e., rotating towards or away from each 
 other), can be conveniently mounted also either in a pho- 
 rometer or in a stereoscope. Training in the consulting 
 room however is only practicable for those surgeons who 
 are blest with sufficient leisure. 
 
 5 Operation. This generally is the last resort after we 
 have helped nature to do her best. It is invaluable in some 
 cases and especially when we can convert a non-comitant 
 deviation into a comitant one (Duane). Hence before 
 operating, the whole field should be measured to find a weak 
 muscle, the operation should be planned so as to simultan- 
 eously correct any cyclophoria, and in lateral deviations any 
 hyperphoria. Lastly, the strength of the opposing reflex 
 should be measured by prism-vergence, especially for a tenot- 
 omy. I say the opposing Teflex because it is not enough for 
 the opposing muscle to be strong. (For example, however 
 strong the internal rectus may be, we shall obtain no effect 
 from tenotomy of the external in the primary position if the 
 converging reflex is inactive. The internal rectus may be 
 
 45 
 
AMERICAN JOURNAL OF PHYSIOLOGICAL OPTICS 
 
 Strong for phasic motions, and yet the posture be weak.) 
 Exercise of the convergence, however, may often be trusted 
 to bring about a sufficient augmentation of the reflex to 
 make tenotomy advantageous. I have had excellent results 
 from graduated tenotomy of an inferior rectus for old stand- 
 ing paralysis of the opposite superior oblique (restoring the 
 head, for example, in the case of one medical friend to the 
 erect position, after being tilted for years toward one 
 shoulder). Even cyclophoria is sometimes worth operating 
 for. I have recently seen a patient on whom I operated 
 for this more than twelve years ago. Previously to the 
 operation he had headache without intermission for seven 
 years dating from typhoid, and he has had no headache 
 since. But these operations are extremely tricky, and in 
 higher heterophoria it is rather a responsibility to convert a 
 comitant defect into a non-comitant one by operation. 
 Here again, however, nature comes to the rescue, and grad- 
 ually restores more or less comitancy if a muscle is only 
 tenderly dealt with by operation, on the principle of "rever- 
 sion to organism" as we might call it. 
 
 The most successful surgeon is the one who respects nature 
 most. You may perhaps wonder that I have said nothing 
 about the evolution of the oculo-motor apparatus, but, gentle- 
 men, when I look at your intelligent faces, and the soul in 
 your eyes, I cannot bring myself to believe that you are de- 
 scended from maggots and spiders and pigs. The whole voice 
 of nature, as I hear it, is against that fantastic theory. 
 Nature is conservative and not progressive. She reverts 
 to type as soon as the reason for departure from it dis- 
 appears. When I see a piano, I do not at once jump 
 to the conclusion that because the keys are in progressive 
 series, therefore they must have evolved out of one another! 
 
 I thank you, gentlemen, for your kind attention, and I 
 have now the pleasure of laying this imperfect lecture as a 
 little memorial wreath upon the tomb of our friend and 
 benefactor, Robert Walter Doyne. 
 
 Glenartney, Poole Roaci, 
 Bournemouth, England. 
 
 46 
 
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