Retinopathy: an overlooked adverse effect of interferon-beta treatment of multiple sclerosis.

Interferon (IFN), which is an established maintaining therapy for multiple sclerosis (MS), has been reported various adverse effects. This paper describes a case of IFN-associated retinopathy, representing an overlooked adverse effect in MS. A 46-year-old woman with diabetes mellitus was diagnosed with MS and treated with IFNbeta-1b for three years. She displayed sudden defect of the visual field and ocular fundi showed retinal cotton wool spots indicating IFN-retinopathy, which resolved rapidly after IFN was discontinued. To evaluate the prevalence of retinopathy in MS, we performed fundoscopic examination on twenty MS patients treated with IFNbeta-1b in our hospital. However, none of the patients displayed retinopathy. Only four other cases of IFN- retinopathy in MS have been reported in the literature. Therefore, IFN-retinopathy may be uncommon in MS, but neurologist should be mindful of this adverse effect and regularly check the fundus, particularly in patients with possible risk factor, diabetes mellitus.