Visual impairment in Parkinson's disease treated with amantadine: Case report and review of the literature

A 61-year-old man with Parkinson's disease (PD) developed sudden-onset visual impairment after initiation of amantadine treatment. Ophthalmologic examination revealed corneal endothelial edema. Discontinuation of amantadine resulted in rapid improvement of visual acuity. A review of the literature indicated only a few reports of amantadine-associated corneal dysfunction in patients with neurological disorders as well as influenza syndrome, but none with PD. Amantadine-associated visual impairment in PD could be possibly overlooked, since PD mainly affects elderly people who often develop aging-related ocular changes. The present report alerts neurologists and physicians in general to the peculiar ophthalmologic side effect of amantadine.