Contrast thresholds of diabetic patients determined by VECP and psychophysical measurements.

VECPs to checkerboard pattern reversal (12 Hz reversal) at different contrast levels were measured in normal subjects and in patients suffering from diabetes mellitus, with visual acuities above 0.8. VECP contrast threshold was obtained by extrapolating VECP amplitude vs contrast on a log scale to zero microV. Results were compared with psychophysical thresholds. It was shown that both VECP and psychophysical contrast thresholds were significantly higher in the diabetic patients than in the normal subjects.