Part 11

CASE 21.--Mr. H--, æt. 28, has myopia 6 D., V. 6/9 in the right eye; the left eye has always been weak sighted, emmetropia is detected with the ophthalmoscope, with normal fundus, V. 1/18. No squint, binocular fusion can be proved with prisms.

CASE 22.--Mr. B--, æt. 47, has hypermetropia 5 D., V. 5/9 in the right eye. Left eye with + 5 D., V. 1/18 (a few letters of 12 also were recognised at 1 m.). It seems, however, that the patient is not able exactly to indicate the position of the retinal images of his left eye, he does not know, as he expresses himself, "whether the letters stand here or there." Patient observed the defective sight long ago; the ophthalmoscopic condition is normal. Patient really comes on account of his son, aged 7-1/2, in whom hypermetropia of 3·5 dioptres is detected with the ophthalmoscope, right eye with + 3·5 V. 5/9. Left eye has convergent squint, V. 1/36, No. 3·0 is read with + 6·5 D.

The hereditary tendency is seen also in the following case:

CASE 23.--Mrs. S--, æt. about 46, on the left H. 4 D., V. 5/18 to 5/12, has used no spectacles until now, and reads No. 0·75 without glasses at about 15 cm. R. with + 4 D., V. 1/18, with + 6·5 D. large letters of No. 5·0 are recognised.

Two sons, present at the same time, are hypermetropic. One has in either eye V. 1/4, the other a slighter degree of congenital amblyopia.

CASE 24.--Johanna L--, æt. 4, came under treatment for a congenital fibroma covered with hair, about the size of a cherry-stone, situated on the outer corneal margin of the left eye, which was removed. Three years later, when the child had learnt to read, emmetropia and full visual acuteness was observed in the right eye, with the left No. 4·0 only is read with difficulty. The ophthalmoscope shows a slight degree of irregular astigmatism of the cornea, which in no way explains the defective vision; the image of the fundus is perfectly clear and quite normal.

CASE 25 afforded me a not altogether pleasant surprise. Martin M--, æt. 58, has matured cataract in the right eye, with perfectly satisfactory light reflex, proper projection, &c. On the left progressive cloudiness of the lens has begun. The course of operation and cure were regular in every respect, but the power of vision finally was so small that with a clear pupillary area, and otherwise normal condition, only single words of No. 3·0 were recognised with difficulty at 10 to 15 cm. with convex 20 D. For the first time the patient remembers that he noticed the defective sight in his right eye at the age of sixteen, and was for this exempt from army service. The operation performed later on the left eye procured satisfactory vision.

C. Visual acuteness of less than 1/36 12 cases.

Determination of refraction of the better eye is given in 6 cases, and showed twice emmetropia, twice slight myopia, twice hypermetropia. I only possess an exact ophthalmoscopic determination of the condition of the defective-sighted eye in one instance with H. 2·5 D.

This group is of special interest in that it represents the extreme degrees of congenital amblyopia, and, on the other hand, because it contains 5 cases of children under 10 years of age.

CASE 26.--Constanze von M--, æt. 9-1/2. Defective vision on the left side had been noticed long before by the child's parents. On May 1, 1879, emmetropia was observed in right eye, V. 5/12 to 5/9. No. 0·4 is read at 15 cm. On the left, only movements of the hand are seen, fingers cannot be counted even when close to the eye; the visual field is good, that is, on moving the hand in the periphery of the visual field the child sees "something" without being able to state what it is. Reaction of the pupils as rapid and equal as usual. The ophthalmoscopic condition (even with dilated pupils) is perfectly normal. All tests for simulation were of course applied.

On account of the importance of the case, I suggested another examination a year and a half later, on the 22nd December, 1880, which showed precisely the same result as the former one--optic disc, macula lutea, &c., perfectly normal, the ophthalmoscopic determination of the refraction shows H. 2·5 D.

The child's father also possesses in the left eye a slight degree of congenital defective sight, observed for many years, with normal ophthalmoscopic condition; No. 0·5 is read with + 6·5 D. at 10 cm.

CASE 27.--Tina S--, æt. 6. The defective sight of the left eye had been remarked some months previously; report on July 16th, 1878: R. full visual acuteness, L. movements of the hand are scarcely visible. The child cannot count fingers. Normal ophthalmoscopic condition. Eserine and separate use were prescribed. On September 9th, 1878, fingers were counted with the left eye at 1·5 m., single words of No. 4·0 were recognised, No. 3·5 with convex 6·5 D., but always with oscillating fixation. The improvement in the child's statements may be referred to the fact that she had meanwhile learnt to form right conclusions from the very imperfect sensual impressions of her left eye.

CASE 28.--Frank J--, æt. 10. Left eye. V. 10/50 to 10/40, No. 1-1/2 Snellen is read at 4 inches. On the right, nystagmus on fixation, fingers are counted at 5-6 feet. The ophthalmoscopic condition is normal. A sister of the boy squints.

CASE 29.--Ernest G--, æt. 8, has slight nebulæ on both corneæ. On the left V. 15/40. On the right, fingers are counted at 4 inches with visual axis deviating inwards.

CASE 30.--I operated on Moritz L-- for congenital cataract before he was a year old in 1869 by means of a needle operation. In June, 1877, a thin ophthalmoscopically transparent secondary cataract appeared in both eyes; on the left, with convex 12 D. V. 3/24 to 3/18, with convex 16 D. No. 0·4 is read at 10 cm. On the right, with convex 12 D., fingers are counted with difficulty at about 1 m., with inward deviation of visual axis.

CASE 31 is also worthy of note. Carl H--, æt. 22, shows quite a number of congenital anomalies on the left side of the face, harelip, deformed nostril and a skin defect on the inner corner of the eyelid. There is a congenital dermoid growth of the size of half a pea situated on the inner lower corneal margin. A slight irregularity in the curve of the cornea near the dermoid is detected with the ophthalmoscope; the fundus of the eye is perfectly normal. Fingers are not counted further off than a metre with visual axis deviating inwards. The right eye is emmetropic (perhaps slightly hypermetropic), and has full visual acuteness. There is no squint.

It is customary to "explain" these cases of monocular amblyopia by previously existing squint, and one is quite satisfied if by the examination of patients it is only possible to prove that they have occasionally squinted, although the advocates of the amblyopia ex anopsia disallow the presence of the same under these conditions, that is, in periodic squint. Of course a theory which cannot exist without the assertion that occasional alternation suffices to hinder the development of defective vision caused by disuse, cannot possibly hold periodic squint to be the cause of it. Certainly permanent squint may also disappear, but this much I have been able to determine, that this seldom happens before the twelfth year of life, and one may surely reckon that children in whom permanent squint is developed at the usual early period of life, still squint at the age of ten years. Cases 24 and 26 to 30 can under no circumstances be explained by previous squint, notwithstanding that they represent the extremest degrees of amblyopia, but the question is undoubtedly that of congenital defective vision; moreover I have excluded from the statistics of congenital amblyopia all cases in which the previous presence of squint could even be supposed.

A table of the cases above described with reference to the defective condition is interesting; when a determination of refraction existed for the weak eye I have given it, and when this was not the case I have stated that of the better eye, thus it is seen that among 85 cases in which the refraction was determined, hypermetropia (including hypermetropic astigmatism) was present in 39. Hypermetropia was found then in 47 per cent of all the cases. The percentage would probably be higher, if all weak-sighted eyes had been examined from the beginning as to their state of refraction, but as I only learnt to know the relation between hypermetropia and the higher degrees of congenital amblyopia from my statistics, I did not take notice of this relation when investigating individual cases.

How does congenital amblyopia now stand in relation to that disturbance of vision which we observe in squint? I see no difference; whether squint is present or not, the form of defective vision is precisely the same, and nothing happens in the combination with squint which could not also be proved without it. The relation to hypermetropia, which is proved with congenital amblyopia, also appears in squint.

A collective table of cases of convergent and divergent squint included in the statistics (pp. 19 and 47) shows:

(a) In myopia, emmetropia, and doubtful hypermetropia, with convergent and divergent squint together 329 cases. Among them: Visual acuteness to 1/7 239 " less than 1/7 to V. 1/12 19 " " 1/12 to V. 1/36 46 " " 1/36 25 Defective sight of higher degree than 1/7, 27·3 per cent.

(b) In hypermetropia 1 to 3 D., including the few cases of hypermetropia with divergent squint, 177 cases. Among them: Visual acuteness to 1/7 121 " less than 1/7 to V. 1/12 17 " " 1/12 to V. 1/36 27 " " 1/36 12 Defective sight then, 31·6 per cent.

(c) In hypermetropia 3 D. and more, 70 cases with convergent squint, with: Vision to 1/7 39 V. < 1/7 to V. 1/12 8 V. < 1/12 to V. 1/36 14 V. < 1/36 9 Defective sight then, 44·2 per cent.

This regular increase of defective sight with the increase of the hypermetropia can be no mere accident, and speaks strongly for the identity of defective vision in squint with congenital amblyopia. Were defective vision caused by the squint the various states of refraction would show no difference in the percentage of defective vision.

Further, the circumstance is worthy of remark that among 198 cases of periodic squint (convergent and divergent) which are applicable for the statistics of visual acuteness--

170 possess V. to 1/7. 16 " V. < 1/7 to V. 1/12. 9 " V. < 1/12 to V. 1/36. 3 " V. < 1/36. 14·2 per cent. then of defective vision of considerable degree.