The objective of the study was to determine the benefits of screening for color vision impairment on the ability to operate a motor vehicle safely. The study was cross-sectional in its methodology in which color vision of 1,879 randomly selected drivers was tested using Ishihare color plates. There were 85 (4.5%) cases of defective color vision. Among them, 83 (97.6%) were males and 2 (2.4%) were females. Of the 83 male cases of defective color vision, 56 (65.9%) were deuteranopes and 29 (34.1%) protanopes. The two color-blind females were deuteranopes. During the past 3 years, 27 (31.8%) color-blind subjects were reported to have had road traffic accidents compared to the total accidents of 398 (21.2%). The probability that color-blind drivers would encounter an accident was about twice as high as among non-color-blind drivers (OR = 1.94; 95% CI, 1.18-3.17; P less than 0.02). We conclude that the compulsory examination of color vision in driver's license seekers in Ethiopia does not screen out color-blind individuals. Therefore, the techniques of screening should be improved either to restrict the acquisition of licenses or at least to train drivers to compensate for their defect. (Author/publisher).
Abstract