Visual evoked responses in patients with multiple sclerosis.

The visual evoked response (VER) was evaluated in a series of multiple sclerosis patients and normal subjects. The data showed significant delays in wave peak latencies among the patient evoked responses. The prolonged latencies correlated closely with visual impairment; however, even patients with a previous history of visual impairment, but with no deficits noticeable on examination at the time of study, showed a delay in wave peak latencies. The results further suggest that the VER is primarily altered when there are central field defects.