Contrast sensitivity in multiple sclerosis. A study in 35 patients with and without optic neuritis.

Binocular and monocular contrast sensitivity (CS) functions were determined for 35 patients with multiple sclerosis (MS) of whom only 21 had a history of optic neuritis. CS was abnormal in all 21 of these patients; alterations of CS affected all spatial frequencies, not only for the eye with optic neuritis, but also for the clinically unaffected eye (p less than 0.01). Approximately one third of the 14 patients with MS but without any history of past visual disturbances showed an optic nerve involvement. Our results show that (1) clinically visual impairment is bilateral, even if optic neuritis seems unilateral, and (2) CS can detect silent lesions of the visual pathways in MS and may prove to be more sensitive than visual evoked potentials.