Sclerotico-choroiditis posterior : with cases and illustrations / by Henry D. Noyes.

  • Noyes, Henry D. (Henry Drury), 1832?-1900.
Date:
1860
Catalogue details

Licence: Public Domain Mark

Credit: Sclerotico-choroiditis posterior : with cases and illustrations / by Henry D. Noyes. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    The examination of the posterior segment of the eye by means of artificial light reflected upon it, has brought to view many pathological conditions with which oculists were formerly imperfectly or not at all acquainted, and has imposed upon them new labors in endeavoring to establish their seat, their nature, their succession, and, so far as possible, their causes. When means of investigation have been but recently introduced, much obscurity must yet remain ; yet, before all the details have been elucidated, much is done in establishing a correct diagnosis, and important aid is offered in settling the question whether treat- ment is likely to prove beneficial. In revealing opacities of the transparent media, the crystalline lens, its capsule, and of the vitreous body, the ophthalmoscope is almost unerring. Specks and strijB in the lens are clearly seen with a dilated pupil, and the same is true of deposits upon the capsule. In one instance the diagnosis is rather difficult, namely, when the opaque spot is situated upon the centre of the posterior capsule,_no other opacity being present. The reason is, that the speck is so close to the mathematical centre of the globe that when the eye is moved in different directions it can make but a very slight amount of motion, and seems to coincide with the reflex from the surface of the cornea. This difficulty can be obviated hj looking from a point a little more sidewise, and also by inspecting the lens obliquely under light concentrated upon it by a double convex lens. The existence of particles floating in the vitreous humor, whether shreds of fibrin, or blood-clots, or the presence of the cysticercus, or the more-difiused and less-discernible turbidity of the humor, is made known by the light of the ophthalmoscope. The impairment of vision which sometimes follows iritis, where the pupil is not obstructed by lymph, and its margin but slightly or not at all adherent to the anterior capsule, is often well explained by the discovery of flocculi of plastic exudation into the corpus vitreum, proving that the inflammation ha.d ex- tended to the ciliary body. The examination of the optic nerve, the retina, and the choroid coat requires more careful inspection and a practiced eye. To decide the nature of the discovered lesions is not always easy, and often, though sight is impaired, nothing is revealed to the most expert scrutiny. Tiiere arc sources of^ fallacy to deceive the observer, and there may be functional disturbances which leave no visible trace. It is proper to observe that con- centrated light should always be used with caution, not too