The Prevalence of Congenital Color Blindness and its Effect on Contrast Sensitivity and Depth Perception

Color blindness is a common disorder. The congenital type of color blindness is sex-linked and the genes are located on the X chromosome. The prevalence of color blindness among males and females are 5-8 % and 0.5 % respectively. Color blindness can affect daily activity as a disability. Therefore, the aim of this study is finding the prevalence of color blindness and its effect on contrast sensitivity and depth perception among school children in Mashhad.

Four thousand four hundred school children (2408 males and 1992 females) were selected randomly and tested by Ishihara for detecting color blindness. At the second step, the students with color blindness were examined at optometry clinic by Ishihara test again. Two hundred students were also selected randomly to classify in a control group, Cambridge and Titmouse tests were taken on the case and control group.

Among 4400 schoolchildren, 3% suffered from color blindness (5.1% in boys and 0.4% in girls). Ishihara test showed 2.2% deuteranopia, 0.8% protanopia and 0.6% suspect. The results indicate that the congenital color blindness has no effect on contrast sensitivity and depth perception.

The present report provides valuable information regarding color vision defectiveness among schoolchildren. Effective detection of this anomaly is expected to prevent from substantial effects on their education and future job. It is strongly recommended to perform color vision test at the beginning of a child’s education.