Color blindness or color vision deficiency is the inability or decreased ability to see color, or perceive color differences, under normal lighting conditions. Color blindness affects a significant percentage of the population. There is no actual blindness but there is a deficiency of color vision. The most usual cause is a fault in the development of one or more sets of retinal cones that perceive color in light and transmit that information to the optic nerve. This type of color blindness is usually a sex-linked condition. The genes that produce photopigments are carried on the X chromosome; if some of these genes are missing or damaged, color blindness will be expressed in males with a higher probability than in females because males only have one X chromosome (in females, a functional gene on only one of the two X chromosomes is sufficient to yield the needed photopigments).
Color blindness can also be produced by physical or chemical damage to the eye, the optic nerve, or parts of the brain. For example, people with achromatopsia suffer from a completely different disorder, but are nevertheless unable to see colors.
The English chemist John Dalton published the first scientific paper on this subject in 1798, "Extraordinary facts relating to the vision of colours", after the realization of his own color blindness. Because of Dalton's work, the general condition has been called daltonism, although in English this term is now used more narrowly for deuteranopia alone.
Color blindness is usually classed as a mild disability, but there are occasional circumstances where it can give an advantage. Some studies conclude that color blind people are better at penetrating certain color camouflages. Such findings may give an evolutionary reason for the high prevalence of red–green color blindness.
Other articles related to "color blindness, color, blindness, colors":
... Color blindness or color vision deficiency is the inability or decreased ability to see color, or perceive color differences, under normal lighting conditions ... Color blindness affects a significant percentage of the population ... There is no actual blindness but there is a deficiency of color vision ...
... Color blindness very rarely means complete monochromatism ... In almost all cases, color blind people retain blue–yellow discrimination, and most color-blind individuals are anomalous trichromats rather than complete dichromats ... discrimination along the red–green axis of color space, although their ability to separate colors in this dimension is severely reduced ...
... Color codes present particular problems for those with color deficiencies as they are often difficult or impossible for them to perceive ... Good graphic design avoids using color coding or using color contrasts alone to express information this not only helps color blind people, but also ... Designers need to take into account that color-blindness is highly sensitive to differences in material ...
... Color blindness affects a significant number of people, although exact proportions vary among groups ... a restricted gene pool sometimes produce high proportions of color blindness, including the less usual types ... More than 95 percent of all variations in human color vision involve the red and green receptors in male eyes ...
... While many aspects of aviation depend on color coding, only a few of them are critical enough to be interfered with by some milder types of color blindness ... Some examples include color-gun signaling of aircraft that have lost radio communication, color-coded glide-path indications on runways, and the like ... credentials to persons who suffer from color blindness for this reason ...
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