burnett: ring-scotoma. of ring-scotoma. rence or is deemed

BURNETT: Ring-Scotoma.

CLINICAL CONTRIBUTIONS TO THE STUDYOF RING-SCOTOMA.

BY SWAN M. BURNETT, M.D.,WASHINGTON, D. C.

FROM the relative paucity of reported cases, it might beinferred that ring-scotoma is either of very infrequent occur-rence or is deemed of no special importance or interest bythe practitioner; and yet I am inclined to believe that it willnot be found of any exceeding rarity if it is searched for inthe proper cases, and from my present point of view it is, forsome considerations at least, of as much importance as theconcentric or sector-like defects in the visual field for whichwe are on the qui vive, and to which we attach such diagnosticvalue.

Within the last three years two cases of ring-scotoma havecome under my care, which I have been able to watch andexamine at intervals for the space of two years. In most ofthe cases reported the results of a single examination only aregiven, and in none have the changes been noted for a lengthof time equal to mine; in fact, in but two or three instancesis any account given of the subsequent history of the caseafter the first examination. I consider a knowledge of theprogress of the affection to be of prime importance if we areto arrive at anything like a correct knowledge of its pathologyor a proper appreciation of its significance as a symptom. Allthe authors who, in writing on the subject, have attemptedto locate the lesion, have, I believe, placed it in the choroid,or at least within the globe. It has seemed to me, from astudy of my two cases, and from the data furnished from othersources, that there is at least a warrant for questioning theaccuracy of such a position, and for a reexamination intothe falcts on which it is based. It is my belief that the phe-nomena can be more readily explained on the supposition of

55

43S

436 BURNETT: Clinical Contributions

a nerve or tract lesion. The basis of this belief can be betterunderstood after a brief history of the two cases.CASE I.-J saw Mr. J. S. O., a man of sixty years, for the

first time on May 6th, I885. On the 6th of the precedingJanuary he had been attacked with an inflammation in theleft eye, which had continued for some time. I found closureof the pupil from iritis. V. = -e-f. Within the last few daysthere had appeared a cloudiness of vision in right, and it wasfor this that he now sought advice. Vision, as tested at thattime, = -, and there was the usual picture of ckoroiditis serosa.The disk was veiled and there were some floating opacitiesin the vitreous. He denied having ever had syphilis, thoughhe had gonorrhcea forty years ago; has had rheumatismoff and on for several years. He was put on mercury andthe iodides. He got on fairly well, his vision for the test-letters constantly improving, but yet he complainied that hehad the greatest difficulty in getting about.On the 7th of June, though his V. 4=, he had to be led

to my office, because he could not see the curb-stones or otherobjects on the ground in front of him. I then examined hisvisual field for the first time and found it as recorded in Fig. I.

FIG. I. FIG. II.

so"

The limits'of the scotoma were sharply defined, particularlyon the inner margin, which I consider accurate to within 3'.The outer limits cannot be relied upon for less than 5. -Theophthalmoscopic picture had not changed in any essential

to the Study of Ring-Scotoma.

particular. There were no gross changes in the region sur-rounding the macula to which the scotoma could be referred.On the ioth of June, the form of the scotoma had changed

to that given in Fig II. Central color perception, which wasat that time examined, was good, and the visual field of theleft eye wvas found to be free from any defect.On the 27th of July, there was an attack of iritis in the

right, which lasted three weeks, leaving V. - -4 on the I 5thof August, when the field, as represented in Fig. III., wastaken. It will be noted that the ring is at this time broken,the central clear spot remaining as it has done from the be-ginning, essentially the same. There was no perceptiblechange in the appearance of the vitreous and choroid.

FIG. III. FIG. IV.

On the 31St of Aug-ust, a change to that given in Fig. IV.was found, and V. had advanced to -.On the 2d of December the ring had the form given in

Fiig. V., and distant V.==. He was, however, able to readthe newspaper, though not without difficulty, since he couldnot make out the whole of a very long word at once, and thepassage from the ending, of one line to the beginning of thenext was difficult. A careful examination at this time failedto reveal any unusual changes in the choroid around themacula. There was no disturbance of the pigmeint, and itoffered to view no alterations different from the remainingparts of the fundus.

437

10,

BURNETT: Clinical Contributions

The patient was seen no more until the 21St of March, i887.The V. F. was then as given in Fig. VI. V. was not so good,being only 5, but was increased to A& by -2.5. He wasable, however, to read No. 2 of Wecker's scale without anyglasses, and No. i with + i. In other words, within the lastyear a myopia had developed consequent upon a posteriorstophyloma probably, a not at all uncommon occurrence inchronic choroiditis. Another careful examination, however,failed to discover any changes in the region corresponding tothe ring to which it could be justly referred.

FIG. V. FIG. VI.

CASE II.-Mr. J. B. W., a man fifty-five years of age, con-sulted me for the first time on January I2th, I884. He hadbeen infected with syphilis two years before, and was treatedsoon after in Boston for some trouble with his eyes. LastSeptember his V. became worse, and he was again examinedthere and his trouble pronounced cataracts, and he was told towait until their maturation. His vision getting so bad while ona visit to Washington that he could scarcely get about alone,he came to me. I found V. = 4 in both eyes, with nio defectin color-perception. The ophthalmoscope showed turbidityof the vitreous, fine in left, but with one quite large mass ofopacity in right. There were no chang,es in the choroid thatwere at all marked, and the retinal vessels wereabout nornmalin size and course. There were some sli]Wht iritic adlhesionsin left, and dots of pig,ment on the capsule in both; othe-wise

438

to the Study of Ring-Scotomna.

the lenses were clear. His vision was very much worse atnight, and there were some photopsias. An examination ofthe V. F. F. revealed a complete right hemianopic defect,with a perfect reg-ular ring scotoma in the left field in right,and an irregular ring-scotoma in the left. (Figs. VII. andVIll.) Put on mercurial inunction.

FIG. VII. FIG VILa.

January 29th. On the 25th inst. had very severe headache,

~~~~~~~~~~~~~~V _4

and numb sensation on the left side of the body. V. =Vitreous seems a little clearer. In the right the whole ofthe left visual field is clear; in left there is complete righthemianopsia and a slight remainder of the ring extendinginto the left field. (Figs. VIII. and VIIla.)

FIG. VIII. FIG. Vlla^.

On the 7th of February, the fields were as shown in Figs.IX. and IXa. The ophthalmoscopic picture had not changed.V. 4

439


On the 25th of February, the dark regions were not abso-lutely dark, there being some sense of luminosity; their forms,however, remained essentially the same. V. = 4

FIG. IX. FIG. IXa.

On the iith of March, V. and V. F. F. were about the same.Can distinguish red, green and blue up to IC) from point offixation, but not beyond. Vitreous seems to be clearing.

FIG. X. FIG. Xa.

_

When he was next seeni on t-he 24th of May, there was a'notherchange in ~he V. F. F. as shown in Figs. X. and Xa. In th'eright the ringy had ag-ain made its appearance in the leftfield, while in the left there werc~only two complete defectsin the field, a large pyramidal one downward and inward, anda smnall ohe jwust outwardl from the point of fixation. There

440


was, however, in addition to these, an annular space of di-minished visual sensation, as shown in the shaded part of Xa.

In July both fields had improved, the left being almost cleal,the right clearing in its lower outer portion. V. 4=, centrally.

FIG. XI.

The patient was not seen again until January 22, i885.In left V.== %&, with a normal field of vision; rightV=,with a field as shown in Fig. XI. There were some distur-bances of the choroidal epithelium noted in the right at theinner side of the o. d.

FiE. XII. FIG. XIIa.

10S

On the 14th of February the conditions were essentiallythe same, but while the visual field in the left was free to theperimeter test, there were spots where it was foggy, particu-larly in the lower portion. A drawing made at that time by

441

0


the patient himself, of his field in the right, correspondedclosely with Fig. XI., and he stated that what was seen in theright was as if seen through frosted glass with numberlesspin holes.When seen for the last time on the 17th of November, I 885,

the fields had the forms of Figs. XII. (R.) and XIIa. (L.).V. - 4 in right with-i.5, and the same in left with-0.75.The vitreous was clearer, and there were some marked dis-turbances of the choroidal epithelium downward and outwardin the right, reaching nearly up to the macular region. Therewere also disturbances in the left upward and slightly inward,about six or eight disk diameters from the o. d.

The literature of ring-scotoma, at least so far as I havebeen able to hunt it up, is not abundant. The articles I havefound bearing on the subject are given in the appended biblio-graphy. The chief papers are those of von Graefe (2) (3), thediscoverer of the condition; of Schoen (I3), and of Hersing (4).The majority of the text books pass it by entirely or accordit only a mere mention. Noyes (8), however, gives threecases, all associated with retinitis pig-nentosa, and Juler (6a)calls attention to our want of accurate knowledge concerningit, while recogizing its possible value as a symptom.As rematked at the beginning of this paper, while there is

no unanimity of opinion as to the precise seat of the lesion,the majority place it in the interior of the eye, and all of these,except Hersing, in the choroid, manifesting itself either as achoroiditis or as a part of the pathological processes in retinitispigmentosa. The apparent cause for such a view is the factthat in a majority of the cases of ring-scotoma there is anassociated choroidal affection, and the rather natural inferencehas been that they stood to each other in the relation of causeand effect. The great obstacle in the way of acceptance ofsuch a view is the other fact mentioned by all, that in not asingle case have the visible choroidal changes been found tocoincide with the subjective defect. In one of our cases therewere no determinable gross changes in the choroid, certainlynot in the region corresponding to the scotoma, and in the

442

to the Study of Rizg-Scotoma.

other the changes found were not in such a position as tocause the defect in the visual field. Some, particularlySchoen, endeavor to avoid the difficulty by assuming thatthere may be changes in the choroid affecting the retina whichare not visible with the ophthalmoscope. This, it seems tome, is begging the question. Hersing assumes that in hiscase there was an infiltration in the retina which caused totalblindness in the first instance, but which was eventually ab-sorbed, leaving, however, a circular defect around the maculaas a sequela.On the other hand, Graefe, in his first case, evidently con-

sidered the lesion to be extra-ocular, and there are other cases,-that of Landolt's (9) among others,-in which there was nochoroidal affection whatever, but, on the contrary, an impli-cation of the nervous apparatus. I admit a possibility of thechanges in the pathological process causing retinitis pigmen-tosa being such as to cause a concentric circular defect,because the law of concentricity seems to be almost invari-able in the affection, and it might under some circumstances,not at present clearly understood, assume the form of a ring,but for the ordinary chroiditis it seems to me quite impossiblethat the exudation should stop sharplr at a limit of IO to 200from the macula, leaving the centre of the field, as it is insome instances, absolutely intact. It seems much morenatural for us to look to an affection of the conducting nervefibres, rather than to disturbances in the recipient retinalelements as a cause of the anomaly, particularly in the light ofour recently acquired more accurate knowledge of the mnannerin which the optic nerve fibres distribute themselves to thedifferent parts of the retina and their pretty clearly demon-strated groupings and course in the tract, chiasma and nervetrunk.We know now from the observations of Bunge (i), Samel-

sohn (I2), Vossius (I5), Leber (IO) and others, that there is acertain group of fibres which go to the macular or papillo-macular region of the retina, and that this group, while re-maining intact as a whole, gradually changes its form andposition relative to the other groups from the tract to -the optic

56

443


disk. Those cases t¶f central scotoma dependent upon cir-cumscribed retrobulbar neuritis which have come to a postmortem examination, show an almost invariable course forthese macular bundles as follows

In the tract they lie on the veentral edge and in the upperouter quadrant; in the chiasma at the floor of the recessusopticus; in the intracraniial portion of the nerve pretty nearthe centre of the trunk; after they pass the foramen they grad-ually change their positionl, so that when they reach the pointof entrance of the retinal vessels they lie on the temporal side,and at the entrance to the globe form the outer lower sectorof the nerve trunk. (Vossius, I5.)

Bunige (i) has endeavored to show the manner of dispositionof the different bundles of optic nerve fibres in the retina,and has been able to demoinstrate a pretty clear division into:i, papillo-macular, which is again subdivided into severalsections; 2, the intermediate; and, 3, the peripheral.These bundles seem to be quite distinct from each other,

and they all changre their positions relative to each other intheir passage from the tracts forward.The point of patholog-ical and practical interest to be de-

duced from this anatomical arrangement is that in ring-scotomawe probably have the intermediate fibres affected by a cir-cumscribed neuritis of the same nature as that which affectsthe macular fibres in the cases of central scotoma, leaving theperipheral and macular bundles intact; or it is possible thatthere may be pressure on these fibres where they lie on ornear the surface, by an exudation or growth from some con-tiguous tissue. Our second case lends much plausibility tosuch a view. There was, at the beginning, a complete righthemianopsia, with left semi-annular scotoma. Evidently therewas here, from some cause, a complete loss of transmittingpower on the part of the left tract, with a concomitant impli-cation of the intermediate fibres of the right tract. Only themost far-reaching imagination, I think, could conceive of sucha condition being the result of choroidal disease. I would par-ticularly direct attention to the character of the division linebetween the two halves of the field. It is identical with that

444


which is found in typical hemianopsia, due to tract lesion. It isstrictly vertical, with a rcinitrant angle at, the point of fixation,leaving, central vision intact. I cannot coniceive it possiblethat anything but a nerve-fibre lesion could have caused sucha peculiar visual field.There is another circumstance which points most signifi-

cantly in the same direction, and that is that the central, in-tact, field of vision is in size and shape almost, if not quiite,the counterpart of the central scotoma in the cases of circum-scribed retrobulbar neuritis. Bunge (i) finds that the papillo-macular bundles supply the central area of the retina for anoval space of approximately 200 in the horizontal directionan(l IO° in the vertical. In both of my cases the central clearfield has about this size and shape. Unfortunately my atten-tion was not directed to this point until both patients had passedfrom under observation, and my measurements, by the ordinarymethods, cannot be relied upon for accuracy within 3'. Avery careful examination of this clear central field, by morerefined methods, would, I am sure, reveal a much closer re-semblance between the two than even my diagrams show,and I hope that ftuture observers will pay particular attentionto this point in cases that offer for examination. It will benoticed, too, that in all the changes, some of them very marked,which the fields undergo, this central clear spot is neveressentially reduced in size. It may become enlarged in somedirections, but never concentrically, showing, I think, thatthese maculo-papillary fibres are never attacked as a whole bythe pathological process, whatever it may be.

Bearing in the same general direction is the evidence fur-nished by the changing form of the field, particularly asmanifested in my second case.There was first a total right hemianopsia, with semi-annular

defect in the left field. In sixteen days the semi-annular defecthad disappeared, but the right hemianopsia remained, theophthalmoscopic picture remaining essentially the same. Thedefect in the right fields contracted rather rapidly, so that, ina week, only the upper quadrant in the right and the lowerquadrant in the left were affected. The defect in the left eye

445

BURNETT: Clinical Contributtions

went on from that time gradually narrowing until January,I885, when it became essentially free; but up to that timethere remained a small ring around the central clear spotabout I 50 broad, in which visual perception was much dimmedbut not abolished. In May, I 884, there was an almost circulardefect in the right, the ring- being, however, much broaderthan at any previous time.

In January, i885, it had changed its outer limit somewhat,and the central clear spot had enlarged into a vertical slit.

In November, I885, the left field was free but somewhatnarrowed, with slightly irregular outlines. The right eye atthat time showed also an irregular contraction of the field,with two defects corresponding in position to the site of theformer ring, representing, in fact, the remains of its breakingup. All these changes taking place without any visible changein the ophthalnioscopic picture, and in a somewhat regularand progressive order, can be accounted for, in my opinion,much more logically on the supposition of a varying pressureon the tracts, chiasma, or nerve trunks than by an exudationfrom the choroid.

That these annular defects can be due to affections of thenervous apparatus independent of any retinal or choroidalaffection, is shown by Graefe's (2) first case and by Landolt's (9)case of double annular defect associated with lead poisoning.

I am fully aware, however, that, at present, we are not in aposition to do much more than speculate on the pathology ofthe affection, and these cases, with the remarks thereon, I begto be regarded, not as offering anything positive to the solu-tion of the question, but rather as hints for future investiga-tors and as pointing out a line of inquiry which I believe willbe profitable.

BIBLIOGRAPHY.

i. BUNGE, PAUL.-Ueber Gesichtsfeld und. Faserverlauf imoptischen Leitunigsapparat-Halle, Max Niemeyer. I884.4', 36 pp.

2. GRAEFE, A.-Ueber die Untersuclhung des Gesichtsfeldes beiamblyopischen Affectionen. Graefe's Archiv. B. II. 2. p.274 et seq.

to the Study of Ri;zg-Scotoma.

3. GRAEFE, A.-Exceptionelles Verlhalten des Gesichtsfeldes beiPigmententartung der Netzlhaut. Graefe's Arclhiv. B. IV.2. pp. 250 et seq.

4. HERSING.-Ringforinniger, concentrisclher Gesichtsfelddefect.Graefe's Archiv. XVIII. 2. p. 69.

5, HOCK, J.-Die syphilitisclhen Augenkrankheiten. WVienerKlinik. 1876. p. ioS.

6. IMRE, JOSEF.-Ein Fall von Rinigskotom bei Cliorioretiniitisspecifica. Zehender's Monatsbl. XIV. p. 267.

6a. JULE3RI, H. E.-A Handbook of Ophthalmic Science andPractice. Philadelplhia, Lea Bros. & Co. 1887.

7. NETTLESHIP, E. and EDMUNDS, W.-Two .cases of typicalamblyopia of slow progress, witlh central scotoma, inpatients suffering from diabetes. Microscopical examina-tion of the optic nerve in one case. Trans. of Oplh. Soc.of thle United Kingdon, Vol. I. p. I24.

8. NoYES, H. D.-Diseasesofthe Eye. Wm.Wood&Co. I881.p. 295-

9. LANDOLT, E.-Troubles de la vision observes dans un casd'hemiplegie saturnine. Ann. d'Ocul. Mars, Avril, I88o.

IO. LEBER,THEO.-Graefe u. Saemisch. Handbuch d. Augen-heilk. B. V. p. 6I2.

I I. MOOREN.-Oplhthalmiatriscbe Beobachtungeni. IS67. P. 263.I2. SAMELSOHN, J.-ZLur Anatomie und Nosologie der retrobul-

bhren kNeuritis (Amblyopia centralis). Graefe's Archiv.XXVIII. I. P. I.

I3. SCHOEN, WILHELM.-Die Lehre vom Gesichtsfelde und seineAnomalien. Hirschwald, Berlin. I874.

14. UHTHOFF, W.-Untersuchungen iiber den Einfluss der chro-nischen Alkoholismus auLf das mensclhliche Selhor-gan.Graefe's Archiv. XXXIII. I. P. 257.

I5. Vossius, A.-Ein Fall von beiderseitigem centralem Scotolnmit pathologisch-aniatomischem Befuind. (With full bibli-ogi aphy.) Graefe's Arcliiv. XXVIII. 3. p. 201.

i6. WILBRAND, H.-Ueber Neuiritis axialis. Zehend. Moniatsbl.XVI. p. 505.

447


DISCUSSION.

DR. I-S. D. NOYES.-The record of cases in which ring-scotoma was connected with retinitis pigmentosa, led memany years ago to direct attention to this point, and incases of retinitis pig,mentosa it came to be my habit toalways look for this lesion. I distinctly recall one case in theperson of a physician which I observed during a period ofyears, in and which the ring-scotoma remained unchangedduring the time of observation. There was no reduction inthe concentric limitation of the field. This case impressedme with the idea that ringY-scotoma mig,ht be looked upon asmerely a local lesion.

Within two years, a case has come under observation in ayoung- lady whom I treated many years ag,o for refractiveerror and asthenopic trouble. She is in delicate health, ofconsumptive parentag,e, and at the time of the last observation,seventeen years of age. She came complaining of pain withdimness of vision in one eye. With the ophthalmoscope, Icould find no material lesion in that eye. When, however,I examined her with the perimeter, I found a riincg-scotoma.Finding no local lesion, no symptoms of brain trouble, and nohistory or evidence of hysteria, I was led to search farther foran explanation of this symptom. I discovered what was tome satisfactory evidence of orbital neuritis. This consistedchiefly in the fact that pressure upon the globe elicited un-questionable evidences of pain. This was a feature of thecase for at least two weeks. The patient remained underobservation two months. The ring,-scotoma was removedfrom the macula about 250. This entirely disappeared andvisionl was perfectly restored. I have satisfied myself that ring-scotoma can be due to extra-ocular cauLses, and in this instancethe lesion was to be found on the orbital portion of the opticnerve. AlthougTh these cases are rare, yet if one will searchfor them he will find that they are not so rare as has beenthotught.DR. BuTLL.-A year ago I reported a case to the New York

Ophthalmoscopical Society which may be classed in the samecategory as those of Dr. Burnett. The patient was a gentlemanthirty-six years of age. When two years of age, he fell downstairs and received a severe blow, lacerating the soft parts of thetemple and the external angle of the right orbit. Vision in theright eye was probably partially lost at that date, and a con-vergent squint developed which disappeared after two years.

448

to the Stzudy of Rinqg-Scotomna.

The vision remained the same, counting fingers eccentricallyat two feet.

In 1878, he received a compound fracture of the skull overthe left parieto-occipital region, with depression of the bone.This was relieved by a treplhining operation. Since then, hehas been the subject of epileptiform convulsions of varying- in-tensity and frequency, which have grown less marked duringrthe past year. Of late, he has noticed that he could not seethrouLg,hout a part of the field of the left eye. Examinationishows that in the right eye he can count fingers at two feeteccentrically. In the left eye V. =2-+ central. Accommo-dation was normal.The ophthalmoscope showed rn the right eye a chronic

neuro-retinitis, and in the left eye a neuro-retinitis of low grrade.The perimeter showed a normal field for 200 around the pointof fixation, then an irregular defect in the field all the wayround, varying in width from 5I tO 200. Outside of this, thefield has the normal visual limitations in all directions. Heis a good shot and has no trouble in reading, except that theeyes become easily tired. Refraction is emmetropic. I haveseen this patient within the past two months, and the ring-scotoma remains precisely the same.

DR. KNAPP.-I remember a patient suffering from pigmen-tary retinitis, who afterwards became blind from glaucoma.Between the periphery and the centre he had a ring-shaped, notquite regutlar scotoma. Gradually excavation developed andhe becamne blind. There was nothing in the ophthalmoscopicpictture to account for the scotoma. The ordinary deposit ofpigment, leaving free the macular region, showed no unusualfeature corresponding to the ring. The other eye is the seatof retinitis pigmentosa, but there is no excavation and noscotoma of any kincl, and very little limitation of the field.

DR. MITTENDORF.--I have seen a case of annular scotomain an elderly gentleman suffering with partial atrophy of theoptic nerve. The scotoma extended through from one-six-teenth to one-fifth of the field of vision. What I wish toemphasize is that in this case, likewise, no lesion of the retinaor choroid could be found, except the partial atrophy of theoptic nerve. Dr. Theo. Sachs has recently stated that inchronic glaucoma he has repeatedly found scotomata. I haveexamined five of my cases of glaucoma with this point in view,and I have found it in one, an old lady, who has a distinctperipheral annular scotoma. In this case, likewise, no lesionof the choroid could be found. I think that the opinion cf thewriter of the article above referred to, that not the cho.oid or

449

BULL :-Passive Motion in the

the retina, but the optic nerve is the seat of lesion, wouldexplain the condition better than any thing else, especially inglaucoma, where there is such destruction of the nerve fibres.

DR. WADSWORTH.-A case which I published in I884, inthe Journal of Ophthalmology, seems to me to be very goodevidence of the lesion being situated occasionally in the nerve.The affection involved only one eye and was traumatic, al-though not, I think, from direct injury to the organ. Thepatient was a young man, twenty-six years of age, who hadbeen run over by a heavy wagon, one wheel passing over thechest. I saw him on the third day after the accident. Therewas then some haziness and a few hemorrhages of the retinaof the right eye and central scotoma. In a few weeks all theophthalmoscopic appearances cleared up, and the scotomaresolved itself into a ring-scotoma. There was a central spot,about two inches in diameter at fourteen feet, in which visionwas perfect, Th. Surrounding this was a zonular scotoma, sevento ten inches in width at a distance of fourteen feet. Theouter boundary of the field was normal. There was absolutelyno ophthalmoscopic change to be seen. This condition con-tinued unchanged for several years at least.

PASSIVE MOTION IN THE TREATMENT OFPARALYSIS OF THE OCULAR MUSCLES.

BY CHARLES STEDMAN BULL, M.D.,NEW YORK, N. Y.

THE treatment of paralysis of the ocular muscles is, evenunder the most favorable circumstanices, unsatisfactory, andthe longer the muscles have been paralyzed the more un-

satisfactory are the results of treatment, whether by internalmedication, or external applications, or galvanism. Many casesof syphilitic paralysis improve up to a certain point, and thenthe improvement stops, and thoug,h the paralyzed muscle ormuscles may have regained some of their motility, the annoy-ing diplopia still remains. Other cases are not improved at

all, in spite of all the methods of treatment at our disposal.Cases of rheumatic paralysis are even more obstinate in

450

burnett: ring-scotoma. of ring-scotoma. rence or is deemed

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