Visual function in multiple sclerosis

126 patients with multiple sclerosis and normal visual acuity were submitted to a battery of tests of visual function. The investigation included visual evoked potential, contrast sensitivity by three methods, and a segment of the Farnsworth-Munsell 100 Hue test. 22 of the patients gave a history of unilateral acute optic neuritis and in these the abnormalities were greater in degree. Contrast sensitivity emerged as the most useful test and was abnormal in 92.2% of eyes. Visual evoked potential was delayed in 35.6% and colour vision was abnormal in less than a third. In general, contrast sensitivity was depressed at all frequencies and most of the abnormalities could be identified by testing at a single frequency of 4 cycles/degree.