Development of Bilateral Optic Neuritis Following Nivolumab Treatment for Malignant Melanoma: A Case Report

We report a case of bilateral optic neuritis developing shortly after nivolumab administration for vulvar malignant melanoma. A 69-year-old woman with stage IV disease developed progressive visual field constriction one week after her first nivolumab infusion. At presentation, her decimal visual acuity was 1.2 in the right eye and 0.3 in the left eye, without ocular findings explaining the left visual loss. Goldmann perimetry showed enlarged blind spots and central scotomas bilaterally. One week later, her visual acuity decreased to 0.6 in the right eye and counting fingers at 20 cm in the left eye. MRI demonstrated bilateral optic nerve enhancement on gadolinium-enhanced T1-weighted images, without evidence of brain metastasis. Anti-aquaporin-4 antibody was negative, and multiple sclerosis was considered unlikely. Nivolumab-associated bilateral optic neuritis was diagnosed, and nivolumab was discontinued. Treatment with intravenous methylprednisolone followed by oral prednisolone resulted in rapid improvement in her visual acuity and visual fields. Pembrolizumab was administered without recurrence of optic neuritis. Approximately one year later, eyelash poliosis and sunset-glow fundus developed. At three years, her visual acuity remained 1.2 bilaterally. In patients receiving anticancer therapy who develop visual impairment with minimal ocular findings, neuro-ophthalmic causes should be considered to facilitate prompt diagnosis and treatment.