[Spatial contrast sensitivity in multiple sclerosis]

Spatial contrast sensitivity was measured in 110 patients with multiple sclerosis (definite = 72, probable = 22, possible = 16) as part of a routine evaluation in a neuro-ophthalmological clinic. Results were compared with those of 37 normal controls matched for age. The test was abnormal in 71 p. 100 of patients. Contrast sensitivity was attenuated for 97 p. 100 of the eyes with optic neuritis and visual acuity drop, for 60 p. 100 of the eyes with recovered optic neuritis and for 36 p. 100 of the non affected eyes in the cases of unilateral optic neuritis. Among the 57 patients with normal visual acuity and no history of optic neuritis, 62 p. 100 had abnormal findings. Globally, contrast sensitivity was reduced on the whole spatial frequency range in cases of current optic neuritis, and mostly on the high or high and medium frequencies in the other cases. Our study confirms that spatial contrast sensitivity is the most sensitive of psychophysical methods to detect subclinical visual impairement in multiple sclerosis. Comparison with VEP's was performed in 66 patients. Both tests were roughly equally sensitive, but findings were concordant in only 63 p. 100 of the cases. The use of both VEP's and spatial contrast sensitivity increases the detection of latent optic neuritis.