[Reduced vision in Wernicke's syndrome with symptoms of nystagmus].

A 42-year-old man presented in the Department of Ophthalmology of Holstebro Central Hospital with a history of alcohol abuse, vomiting and weight loss. The initial symptoms of beriberi were stiffness of the legs and a picture of Wernicke's syndrome. He had bilateral loss of horizontal eccentric gaze holding and upbeat nystagmus, and visual acuity was reduced to counting fingers. Visual acuity was tested in the down-gaze position and increased to 0.3 because of reduced nystagmus. The patient's oculomotor function improved dramatically after treatment with thiamine. Wernicke's encephalopathy and beriberi are discussed, highlighting that nystagmus may be the single ocular symptom. It should be considered in the differential diagnosis of bilateral ophthalmoplegia even in the absence of altered mental status.