Volume 1

A dictionary of practical surgery / [Samuel Cooper].

  • Samuel Cooper
Date:
1825
Catalogue details

Licence: Public Domain Mark

Credit: A dictionary of practical surgery / [Samuel Cooper]. Source: Wellcome Collection.

    46/1282 (page 34)
    ae Beer’s Second Species of Amaurosis ; Cat-cye Amaurosis. : This species of the disorder, of which Beer has yet met with but one form, rarely increases to complete blindness ; it occurs chiefly in very old persons, and it is perhaps this affection to which some oculists:have given the unmeaning name of amblyopia senilis. Sometimes, however, this kind of amaurosis takes place in young persons and children; and one circumstance, that demands particular notice, in its nosology, is, that it always takes place either in thin, dwindled, old, gray- headed subjects, nearly in the state of marasmus senilis, in whom consequently the exchange of organic matter is carried on but tardily, or else in young subjects, who are unhealthy, and dis- posed to consumption, hectical adults, emaciated children, and as a consequence of severe injuries of theeye. . While this amaurosis is not perfectly formed, the iris retains its mobility, and the pupil is neither preternaturally dilated, nor contracted 5 but, when once the patient is quite bereft of vi- sion, the motions of the iris are slew, and the pupil larger than in a healthy eye in an equal degree of light. At the bottom of the eye very far behind the pupil, a concave pale gray, bright yellowish, or variegated reddish opacity is deve- loped. By this the eyesight is not merely weak~ ened, but rendered quite confused, since all ob- jects, but especially smallish ones, appear to be confounded together, particularly when the pa- tient tries to inspect closely any determinate body. The further the disease advances, the brighter and more visible is the bottom of the eye, the paler is the colour of the iris (a thing very con- spicuous in dark-eyed persons,) and when once the amaurosis is complete, so that no suscepti- bility of the impression of light is left, then, upon an attentive examination of the eye, one can mostly perceive, at the troubled deeper part of the eye, a very slender vascular plexus, which merely consists of the ordinary ramifications of the central artery and vein, which are now visible at the pale-coloured bottom of the eye. In a ing yellowish, or reddish appearance, but only in certain positions of the eye-ball; and, in this re- spect, it is somewhat similar to the eye of a cat, whence Beer chooses to term the complaint cat- eye amaurosis. The disorder is also not accom- panied with any other essential morbid appear- ances, except the decline of vision, or complete blindness. (Lehre von den Augenkr. B. 2, p. 496.) Beer, in fig. 1. tab. 4. of his second vol. has given, from nature, an admirable representa- tion of this very remarkable species of amaurosis. The differences in the appearances at the bottom of the eye, in this case, from those presented in the early stage of fungus hematodes of. that organ, will be best understood by referring to the On this point, however, i may here briefly state, that, in the cat-eye amaurosis, there is no projection, but, on the contrary, @ concave depression in the axis of vision. Cat-eye amaurosis may be known from incipient cataract, by the opacity being more deeply situated, and having a shining pearly lustre. (See Journ. of Foreign Med. vol. 4, p» 168.) Beer observes, that the causes of this species of amaurosis are so obscure, that whatever is conjecture. After what has been said in the fore- going paragraph is considered, about the particu- lar individuals who are liable to be affected, and the change of the iris to a pale colour, as a con- stant symptom of this case, a suspicion may be nigrum, and of the tapetum of the uvea, in con- sequence of the stoppage of this secretion, may be the cause of the disease. Leer justly remarks, that much might be learned on this point from the dissection of eyes thus affected; but he has never met with the opportunity. The prognosis cannot but be very unfavour- able; for, as the surgeon is ignorant of causes, he cannot know what means ought to be adopted for their removal. It is fortunate, however, that this amaurosis rarely attains its highest degree, but almost constantly remains in the form of a more or less considerable amblyopia. Just as little is yet known respecting any well regulated mode of treatment: all that Beer has- learnt from his own opportunities of remark is, that, in individuals prone to consumption, or somewhat hectical, but not dangerously so, and especially in emaciated children, whose bellies are not at the same time tense and hard, this amau< rotic impairment of sight may sometimes be kept from getting worse, by the careful employment of such general remedies, regimen, and diet, as are calculated to improve the health. But, in the most fortunately managed cases, Beer never knew a step made towards the removal of the disease. (Lehre von den Augenkr. B. 2, p- 497-98.) Beer’s Third Species of Amaurosis, and its Varieties. 1. Of the amaurosis produced by bitters, coal-smoke, or the effect of lead. This amaurosis in its progress presents differ- ent stages, to which the utmost attention must be paid, in order to avoid treating the case wrengly, or producing complete blindness. The limits between these stages, however, are so faintly marked, that one cannot wonder at their being overlooked by a superficial observer. In the first stage, the complaint never induees entire blindness, but only a more or less considerable diminution of vision. A -manifest turgescence of the blood-vessels, not only in the conjunctiva, but in the sclerotica itself; a disagreeable sensation of fulness in the eye; a perfectly motionless state of the iris; a very considerable dilatation of the pupil; and a peculiar undescribable pale-blackness of that open ing, without any appearance that can be called turbidness; a singular pellicle-like cloud, which _renders large objects indistinct, and quite conceals all smaller ones; and, finally, a more or less re- markable trembling of the limbs; are the charac- teristic symptoms of the first stage. On the other hand, says Beer, in the second stage, the patient is quite deprived of vision ; the pupil is exceedingly large ; the iris quite motion- less, even when the eye-lid is rubbed over the breadth of the iris is greatest in the perpendicular direction; nearly every part of the white of the eye exhibits a faint redness; the edges of the |