Cystinosis is a rare
lysosomal storage disease affecting
amino acid metabolism, characterized by the accumulation and crystallization of
cystine in various tissues, primarily in the eye and kidney. The major ophthalmic symptom is
photophobia, which is related to the corneal deposition of
cystine crystals. The
light sensitivity significantly impairs the quality of life of the affected patients, thus, effective ophthalmic treatment to reduce the crystal density is very importance. In the current case report, we present the characteristic ocular clinical appearance and treatment options of
cystinosis by reviewing the literature. A simple aqueous
solution of
cysteamine, which
aids in the dissolution of crystals, has been widely used in topical treatment in the past, however, its therapeutic efficacy is debatable. Recently, a new viscous formulation of
cysteamine has been proposed for ophthalmic treatment. For the treatment of corneal
cystine crystals in our patient, the new viscous format of
cysteamine has been applied, and
therapeutic effects were recorded for a year. Applying the viscous
cysteamine formulation, a marked and gradual decrease in
photophobia was observed in our patient in the first year of the treatment. Anterior-segment optical coherence tomography and in vivo confocal microscopy represented a continuous decrease in the density of corneal crystals even from the first month of the treatment period. The aim of our case report is to present the ophthalmic symptoms of
cystinosis and the results of the first clinical application of viscous formulation of cysteamin
eye drops in Hungary in a
cystinosis patient.