A nonspecific term for congenital or acquired impairment of color discrimination—usually reds and greens but can also be blues and yellows. It seems that more males are affected, with 7% of males showing this deficiency, compared to only about 0.5% of females. Color vision deficiency is not a disease or degenerative condition, though, occasionally, an acquired color vision deficiency may be a symptom of other health problems. (Ref: Contact Lens Council)