MACULAR PHOTOTOXICITY FOLLOWING CORNEAL COLLAGEN CROSS-LINKING IN A PATIENT WITH KERATOCONUS

Introduction: Keratoconus is a progressive degenerative corneal disease of variable severity. Its management includes medical and surgical treatment. Corneal collagen cross-linking is being increasingly used to stabilize the condition. Macular phototoxicity is a well-known side effect of light exposure; however, its incidence after treatment with riboflavin and ultraviolet light is unknown. We report the clinical features of a patient with macular phototoxicity after ultraviolet A exposure and describe the structural and angiographic retinal changes observed in this patient.

Patient, clinical findings, and diagnosis: A 37-year-old man with keratoconus underwent corneal refractive surgery (topography-guided custom ablation with accelerated and high-fluence corneal collagen cross-linking). Postoperatively, he had decreased vision in the operated eye. Ophthalmoscopy, spectral-domain optical coherence tomography, and fluorescein angiography revealed retinal pigment epithelial changes, ellipsoid zone disruption, and window defects, respectively. The patient was diagnosed with macular phototoxicity. His corrected distance visual acuity stabilized at 20/100 after two and a half years.

Conclusions: Macular phototoxicity may occur after ultraviolet A exposure during corneal collagen cross-linking. The use of accelerated and high-fluence protocols might have contributed to its occurrence in our patient.