Accumulation of cystine crsytals in the eye. Patients present with crystal accumulation affecting the cornea and conjunctiva, but crystals can also be deposited in the iris, ciliary body, choroid and retinal pigment epithelium (RPE), and lens capsule. Corneal crystal deposition starts in infancy in the anterior periphery of the cornea, and progresses centrally and posteriorly. The crystals, which have a fine, uniform needle-shaped structure, are diffusely distributed within the corneal tissues. [from
HPO]