Spatial contrast sensitivity in patients with multiple sclerosis.

Contrast sensitivity tests a basic visual function which is not examined by conventional visual acuity testing or visual evoked responses. It is frequently abnormal in patients with multiple sclerosis. The lack of relationship between VERs and SCSF implies that contrast sensitivity measures aspects of the visual system not examined by the conventional electrophysiological technique, probably visual function situated beyond the anterior visual pathway. It is therefore a useful complementary diagnostic test for patients with multiple sclerosis. Both VER and spatial contrast sensitivity separately detect a high proportion of patients with multiple sclerosis. When used in combination, the two techniques give a yield which approaches 100%. Contrast sensitivity testing as used here is cumbersome and time-consuming. Use of fewer spatial frequencies and/or adaptation of VER techniques for estimation of a contrast threshold may be more applicable for clinical use.