Protocol 86-EI-0062 began as a randomized, double-masked, placebo controlled study to evaluate the efficacy and safety of 0.5% topical cysteamine but was subsequently amended as a natural history protocol. Additional protocols conducted at the National Eye Institute (NEI) at the National Institutes of Health (NIH) began after this protocol and tested various formulations of cysteamine topical solution for efficacy and safety in patients with cystinosis. Subjects from these NIH protocols testing various formulations were ultimately transferred to this natural history protocol for open-label treatment once it was established that the formulation within this study was the most effective. All subjects enrolled in this protocol received the most effective cysteamine topical solution formulation in both eyes. The control was defined as the natural course of corneal crystal accumulation in patients with cystinosis. The efficacy data were obtained from all of the studies conducted at NIH evaluating various cysteamine ophthalmic solution formulations from 1986 until 2005. The safety data were collected from 1986 until the termination of this protocol in July 2013.