Corneal sensitivity in nephropathic cystinosis.

We measured corneal sensitivity in 14 patients with infantile nephropathic cystinosis and in 13 age-matched controls. All patients with cystinosis had the pathognomonic anterior segment findings of crystal deposition within conjunctiva and cornea. Transcutaneous stimulation of the supraorbital nerve and surface electromyographic recording of the orbicularis oculi muscle performed on four patients showed a normal afferent limb to the blink reflex. The corneal sensitivity in patients with cystinosis was 3.18 g/mm2; in the control subjects it was 0.43 g/mm2. This difference was statistically significant (P less than .001).