Defective Color Perception Among Car Drivers in Addis Ababa, Ethiopia

Abstract

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 < 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.