Non-nephropathic (ocular) cystinosis is a type of cystinosis that only affects the eyes. It is sometimes called benign or adult cystinosis since it does not cause life-threatening symptoms or kidney disease. The only symptom of non-nephropathic cystinosis is corneal crystal accumulation. Non-nephropathic cystinosis is typically noticed later in life than the other forms of cystinosis. Eye doctors can diagnose non-nephropathic cystinosis if crystals are seen during an eye exam.