Color Blindness

Inability to perceive colors as such. It may be total or partial, and is independent of the other visual functions. It shows itself commonly in a tendency to confound one color with another, as blue with green, or in an inability to perceive a particular color (most commonly red), which is then ordinarily confused with gray or green. It is variously estimated to exist in from 3 to 6 per cent of the population, and is much more frequent in men than in women.