Glare disability in nephropathic cystinosis.

Cystinosis is a rare metabolic disorder in which nonprotein cystine accumulates within lysosomes due to a defect in lysosomal cystine transport. Although cystine accumulates within most ocular tissues, patients with cystinosis generally complain only of photophobia and glare. We measured glare sensitivity in 12 patients with infantile cystinosis and compared their results with an age-matched control population. Ten of the 12 patients with cystinosis had demonstrable glare disability when compared with the control group. Glare disability scores in the patients with cystinosis ranged from 5% to 50%. Dazzle glare resulting from the accumulation of cystine crystals in ocular tissue may account for glare disability seen in these patients and contribute to their complaints of photophobia.