color blindness

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Related to Colour vision deficiencies: protanopia, total color blindness, Color blind

color blindness,

visual defect resulting in the inability to distinguish colors. About 8% of men and 0.5% of women experience some difficulty in color perception. Color blindness is usually an inherited sex-linked characteristic, transmitted through, but recessive in, females. Acquired color blindness results from certain degenerative diseases of the eyes. Most of those with defective color vision are only partially color-blind to red and green, i.e., they have a limited ability to distinguish reddish and greenish shades. Those who are completely color-blind to red and green see both colors as a shade of yellow. Completely color-blind individuals can recognize only black, white, and shades of gray. Color blindness is usually not related to visual acuity; it is significant, therefore, only when persons who suffer from it seek employment in occupations where color recognition is important, such as airline pilots, railroad engineers, and others who must recognize red and green traffic signals. Tests for color blindness include identifying partially concealed figures or patterns from a mass of colored dots and matching skeins of wool or enameled chips of various colors.

Color Blindness


the inability to distinguish colors. Total color blindness (monochromatism), in which no color differences can be distinguished, is rare. (SeeDALTONISM for a discussion of partial color blindness.)

color blindness

[′kəl·ər ‚blīnd·nəs]
Inability to perceive one or more colors.
References in periodicals archive ?
The frequency with which protan and deutan colour vision deficiencies occur.
Future articles will concentrate on acquired colour vision defects, how colour vision deficiencies can be detected, the consequences of such defects, and possible treatments.
The Ishihara test is considered to be the most frequently used test to screen for redgreen colour vision deficiencies.
Acquired colour vision deficiencies can occur in the course of an ocular or systemic disease, or as a side effect of medication or chemical exposure.
77) The investigators concluded that the lens cannot be used as a method of curing patients with colour vision deficiencies, and it should definitely not be used to allow patients to gain entry into occupations where normal colour vision is required.