To investigate the efficacy of a novel computer-controlled color test for the differentiation of congenital and acquired color vision deficiency.Observational cross-sectional study.Thirty-one patients with congenital color vision deficiency and 134 patients with acquired color vision deficiency with a Snellen visual acuity better than 20/30 underwent an ophthalmologic examination including the Ishihara color test, Hardy-Rand-Rittler test, Nagel anomaloscopy, and the Seohan computerized hue test between June, 2003, and January, 2004.To investigate the type of color vision defect, a graph of the Seohan computerized hue test was divided into 4 quadrants and error scores in each quadrant were summated. The ratio between the sums of error scores of quadrants I and III (Q1+Q3) and those of quadrants II and IV (Q2+Q4) was calculated.Error scores and ratio in quadrant analysis of the Seohan computerized hue test.The Seohan computerized hue test showed that the sum of Q2+Q4 was significantly higher than the sum of Q1+Q3 in congenital color vision deficiency (P<0.01, paired t test) and that the sum of Q2+Q4 was significantly lower than the sum of Q1+Q3 in acquired color vision deficiency (P<0.01, paired t test). In terms of discriminating congenital and acquired color vision deficiency, the ratio in quadrant analysis had 93.3% sensitivity and 98.5% specificity with a reference value of 1.5 by the Seohan computerized hue test (95% confidence interval).The quadrant analysis and ratio of (Q2+Q4)/(Q1+Q3) using the Seohan computerized hue test effectively differentiated congenital and acquired color vision deficiency.