RESUMO
To investigate the discriminative ability of contrast sensitivity [CS], color vision and log MAR visual acuity [VA] in detecting functional losses in diabetic participants with and without retinopathy comparing to the control group. In this cross sectional study in 1388 we examined 105 patients in Mashhad Khatam- Al-Anbia Eye Hospital including 70 diabetic patients [35 with retinopathy and 35 without retinopathy] with 35 control group. Contrast sensitivity was examined by means of CSV-1000 E at 3, 6, 12 and 18 cpd respectively. Color discrimination ability was measured with the Farnsworth D-15 test and log MAR VA by Snellen chart. Contrast sensitivity was significantly lower in the diabetic eyes with retinopathy than in the normal eyes in all spatial frequencies. Comparing to the control group, there was a statistically significant CS loss in spatial frequencies of 3, 6, 18 cpd in the diabetic eyes without retinopathy [p<0.05]. The mean log MAR VA and color vision abnormalities were significantly higher in the diabetic eyes with retinopathy than in the normal eyes or the diabetic eyes without retinopathy [p<0.001]. The sensitivity and specificity of the CS test in 6 cpd were 71% and 82% which were significantly higher than other spatial frequencies. The sensitivity and the specificity of the color vision test and VA [log MAR >/= 0.05, Snellen