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.

    32/1282 (page 20)
    the crystalline lens ; but, more deeply in the eye. Nor is it in proportion to the impairment of sight, the patient being quite blind, while the misty ap- ‘pearance is so trivial, that, if it arose from the epacity of the crystalline lens, it could at most only occasion a slight weakness and obscurity of vision ; at the same time, Richter acknowledges, that it must be more difficult to avoid mistake, when a beginning amaurosis is accompanied with this cloudiness in the eye, and, consequently, when the degree of blindness seems to bear some proportion to the degree of mistiness in the pupil. However, in this case, he maintains that the true nature of the disease may generally be known by comparing the ordinary symptoms of the two diseases. (Anfangsgr. B. 3, p. 14.) And, according to Beer, when the pupil is of a true dark gray, or greenish gray colour, a lateral inspection of the eye will show plainly enough, that the cloudiness is in the vitreous humour, or behind it. Sometimes, the pupil appears reddish, quite red, or of a yellowish white colour ; (Lehre von den Augenkr. B. 2, p. 436.) while, in other cases, the interior of the eye, a good way behind the pupil, seems quite white, and a concave light coloured surface may be observed, upon which the ramifications of blood-yessels can be plainly seen, In particular instances, this white surface extends over the whole back part of ‘the eye; while, in other cases, it only occupies a half or a small portion of it. ‘This peculiar appearance has been ascribed to a loss of transparency in the retina itself, and a consequent reflection of the rays of light. (IHaller, Element. Physiol. Tom. 5. p. 409.) Mr. Travers inclines to the opinion, that it arises from a deficient secretion of the choroid pigment, a preternatural adhesion be- twixt the choroid coat and the retina, and a dis- coloration, or resplendent appearance of the latter from this cause. (Synopsis, p. 148.) One of the strongest characteristics of amau- rosis and an incipient cataract, and one most to be depended upon in practice, is reported by Mr. Stevenson to be the difference, which the flame of a candle exhibits in the twa affections. In incipient. cataract, it appears, as if it were in- volved in a generally diffused, thin mist, or white cloud, which increases with the distance of the light ; but, in amaurosis, a halo, or iris appears to encircle, or emanate from the mist, the flame seeming to be split, when at a distance. (On the Nature, &c. of Amaurosis. Lond. 1821.) © There can now be no doubt, that the white- ness behind the pupil must sometimes have ori- ginated from the diseased mass, which, in cases of fungus hzmatodes of the eye, grows from the deeper part of this organ, and gradually makes its way forward to the iris, being always attended with total loss of sight. Putting out of present con- sideration the change of colour within the eye, produced by fungus hzmatodes, the other palish ehanges behind the pupil are not confined, as Kieser supposes, to very old cases of amaurosis, because the alteration is described by Schmucker as taking place especially in examples the forma- tion of which was quite sudden. ( Fermischte Chir. Schrift. B.2.) and Langenbeck has record- ed cases, in which the same appearance happened im the early stage of the disease. (Neue Bibl. B.i, p. 64, &e. self, and in the pupillary margin of the iris, Beer adverts to several important phenomena, with respect to the motion of the iris. Sometimes the iris moves but very inertly, and frequently not at all, though the light be strong, and the upper eye-lid be rubbed over the eye-ball. While, in other examples, a very moderate light will bring on such a rapid contraction of the iris and closure of the pupil, as are never witnessed in a healthy eye. We have also the authority of Richter for as- serting, that, in particular instances, the iris not only possesses the power of motion, but is capable of moving with uncommon activity, so that, in a very moderate light, it will contract in an unusual degree, and nearly close the pupil. (dnfungsgr. der Wundarzn. B. 3, p. 424, Edit. 1795.) Two or three remarkable instances of the active state of the iris, in cases of amaurosis, were some years ago shown to me by Dr. Albert, then staff surgeon at the York Hospital, Chelsea, and I have seen some other similar cases in St. Bartho- lomew’s Hospital. Most of the patients in ques- tion had not the least power of distinguishing the difference, between total darkness and the vivid light of the sun, or a candle placed just before their eyes. Janin sometimes found the pupil capable of motion in this disease, and Schraucker twice noticed the same fact. Such cases, Mr, Travers thinks, can only be explained by concluding the organ to be sound, and the cause of the amaurosis remote, or exter- nal to it. Thus, says he, in a case of circum- scribed tumor, compressing the left optic nerve, immediately behind the ganglion opticum, al- though the blindness was complete, the iris was active. In two young ladies, in whom the eyes, as in the former case, were perfect, and the blindness complete, the iris was even vivacious ; and there was the strongest presumptive evidence, from the symptoms, that the amaurosis was in the cerebral portion of the nerve. (Synopsis, p. 188.) In some anomalous cases, when the strength of the light is suddenly increased, the pupil ex- pands with more or less celerity. I have already adverted to, the occasional sensible state of the retina. Let me next take notice of a case, which sometimes presents itself, and is quite the reverse of this last. 'The nerves of the iris may be paralytic, while those of sight continue unimpaired. Schmucker was acquainted with a woman, whose pupil was uncommonly dis- tended, and totally incapable of motion. Her sight was very weak, and spectacles were of no use toher. She could scarcely discern any thing by day, or ina strong light ; but she could see ra- ther better at night and in dark places. This infirmity of sight depended upon the dilated, pa- ralytic state of the pupil, by which too many rays of light were admitted into the eye; and the reason why the patient could see better at night was, because the pupil, in its natural state, always becomes widened in a dark situation. (See Vermischte Chirurgische Schriften, Von J. Ls Schmucker, Band 2, p. 13, 14.) On this curious part of the subject, it is re- marked by Mr. Travers, that, if the retina be opaque, compressed, or unsupported, the iris