Discrimination of Ishihara Test Plates Through a Red Filter

Aim: The aim of this study was to investigate the Ishihara Color Vision Test performance of color-deficient subjects through red filters. Material and Method: Thirty color-defective male subjects and 30 color normal male subjects were included in the study. The median age was 26.5 (min-max: 17-61) and 28.0 (min-max: 18-60) years in color deficient and in normal subjects respectively. There was no statistical difference between the groups regarding the age (p=0.62). All the subjects were tested with the Ishihara Color Vision Test, 38-plate edition without filter and with red filter from trial lens set and red acetate paper. Results: Through red filters all of the color vision defective subjects were able to read the plates with zero error (p<0.001) and the performance of color normal subjects also increased significantly (p=0.014). In both groups, all the subjects were able to read all the plates without errors. Discussion: It was concluded that the color-deficient subjects can perform Ishihara Test without errors through red filter