Orientational contrast sensitivity and chromatic contrast thresholds in multiple sclerosis

PURPOSE: To investigate abnormalities of orientational contrast sensitivity (CS) and chromatic contrast threshold (CCT) in multiple sclerosis (MS). DESIGN: Case control study. METHODS: Nine subjects (mean age, 42 +/- 11 years; range, 20-62 years) with MS, an expanded disability status scale of 3 or less, and normal visual acuity (VA) (logarithm of the minimum angle of resolution[logMAR] VA less than .1) in the tested eye were age-matched with 20 controls. Achromatic CS and CCT were mead sured using static, computer-generated sinusoidal grat- ings displayed on a high-resolution monitor. The CS and CCT of each subject were determined using a randomized double-staircase reversal algorithm; CS was measured at five spatial frequencies with horizontal orientation and three with vertical orientation; CCT was measured along the red,green and tritan confusion axes. The sensitivity thresholds of subjects were examined in relation to the mean sensitivity of controls for each spatial frequency. RESULTS: Two subjects had loss of horizontal and vertical CS, and three had isolated vertical loss. When compared with the control mean, there were significant reductions in red,green (P =.016) and tritan (P =.016) discrimination thresholds. CONCLUSION: This study used a computerized psycho, physical test designed to minimize many of the test errors associated with earlier studies. It provides confirmatory evidence that MS may be associated with a loss of orientational CS and color vision, in the absence of reduced VA. (C) 2004 by Elsevier Inc. All rights reserved.