IRIS, CILIARY BODY, AND CHO ROID, DISORDERS OF.—The iris, cil iary body, and choroid, constituting the "uveal tract,"—the vascular or nutritive coat of the eye,—are best considered to gether.
The inflammations and degenerations that commonly affect the uveal tract are especially dependent on constitutional conditions.
Anomalies of the Iris and Choroid.— ALBINISM.--Absence of pigment in the uveal tract accompanies the lack of pig ment in the hair and skin throughout the body. The iris has a dull, gray-blue color, the pupil by ordinary illumination may appear red. With the ophthal moscope, red funclus-reflex may be seen through the iris, and the choroidal ves sels are distinctly visible against tbe yel lowish-white background of the sclera. Such eyes usually present high errors of refraction, for which correcting lenses should be worn.
Instance of partial albinism of the iris in a man, 57 years old, who showed evi dences of an anterior chorioretinitis com plicating a peripapillary choroiditis. 13y
focal illumination the iris presented a uniform coloration; its anterior layers »-ere normal, and -there were no signs of pathological change. 'When light was thrown into the eye, however, by the mirror of the ophthalmoscope, the in ferior half of the iris permitted the rays to pass through its meshes. Thought to be due to congenital lack of development. Dujardin (Jour. des Sciences Med. de Lille, Jan. 6, '93).
Light irides held to be a variety of albinism, an arrest of development of the pigment-gramiles. arising from an im perfect nutrition of the anterior section of the eye. Malgot (Rec. d'Ophtal., Aug., '95).