Lectures on the theory and practice of the ophthalmoscope / by Henry Wilson.

  • Wilson, Henry.
Date:
1868
Catalogue details

Licence: Public Domain Mark

Credit: Lectures on the theory and practice of the ophthalmoscope / by Henry Wilson. Source: Wellcome Collection.

    127/172 (page 107)
    ON THE CHOR OID. Congenital Peculiarities.—The pigment is occasionally partly deficient, or altogether absent in both the choroid and the iris, and the pupil presents the well-known reddish reflection seen in albinos; although the pigment may be absent, yet the epithelial cells them- selves may still exist. In consequence of the non-pigmentation of the ii-is and choroid, light enters the eye on all sides, through the iris, sclerotic and choroid, and instead of being absorbed to a great extent as usual, is reflected backwards and forwards within the eye, from the reflecting white surface of the sclerotic; bearing this in mind, it can be readily understood how this reflected and diff'used light must interfere with the proper formation of an image on the retina, and why the albino is amblyopic. The myopia which so generally accompanies albinism may be accounted for by the fact of the person habitually seeking a dim or very modified light, in order to shut out this disturbing light; in this dim light he is obliged to bring the object close to the eye, and he gets the habit of accommo- dating for his near point. Otto records, in his anatomical descrip- tion of 600 monsters, published at Breslau in 1842, an instance of cyclopia, in which the choroid and the sclerotic were of a gelatinous consistency; in this same malformation two choroids are found. Total absence of the choroid has been found together with numerous other anomalies of the globe; and v. Ammon alludes to partial deficiency of the membrane with spots of union scattered through It. The most mteresting congenital anomaly is one easily seen by