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 ?
67) It has generally been agreed that this lens is not a cure for colour vision deficiencies, but opinions vary on its ability to improve the colour discrimination of daltonians.
32) A review of colour vision deficiencies in primary open angle glaucoma (POAG) estimated that 20-40% of patients have normal colour discrimination, 30-50% have tritan like defects, 5% show red-green defects, and 20-30% have a general loss of chromatic discrimination.
The anomaloscope is the definitive test for red-green colour vision deficiencies against which the results of other tests are compared.
47) It is now known that colour vision deficiencies are genetic in origin (33) but the word "daltonian" is still used to describe individuals with inherited colour vision deficiencies.
Tinted lenses have traditionally had many applications in optometric practice but one of the first tools that was invented to enhance colour perception for those with colour vision deficiencies was the X-Chrom contact lens, invented and patented by Zeltzer in the USA in 1971.