Types of Color Blindness

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I came across some interesting sites about Color Blindness: Never really thought about this before- how does a color blind person pick out glasses? Do all color blind people know they are color blind? 

Vision Simulator– Is a site about the causes of color. Offers some images and you input your ‘stimulation’ and the picture changes under Normal, Red-green deficiency, Blue-Yellow Deficiency, and Monchromacy. If you have some time, take a look at this site- 

Source- Colorlovers

Types of Color Blindness

There are three types of inherited or congenital color vision deficiencies: monochromacy, dichromacy, and anomalous trichromacy.

Monochromacy

 

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Monochromacy, also known as “total color blindness”, is the lack of ability to distinguish colors; caused by cone defect or absence. Monochromacy occurs when two or all three of the cone pigments are missing and color and lightness vision is reduced to one dimension.

Dichromacy

 

Dichromacy is a moderately severe color vision defect in which one of the three basic color mechanisms is absent or not functioning. It is hereditary and sex-linked, affecting predominantly males. Dichromacy occurs when one of the cone pigments is missing and color is reduced to two dimensions.

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Protanopia is a severe type of color vision deficiency caused by the complete absence of red retinal photoreceptors. It is a form of dichromatism in which red appears dark. It is hereditary, sex-linked, and present in 1% of all males.

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Deuteranopia is a color vision deficiency in which the green retinal photoreceptors are absent, moderately affecting red-green hue discrimination. It is a form of dichromatism in which there are only two cone pigments present. It is likewise hereditary, sex-linked, and present in 1% of all males.

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Tritanopia is an exceedingly rare color vision disturbance in which there are only two cone pigments present and a total absence of blue retinal receptors.

Trichromacy

 

Anomalous trichromacy is a common type of inherited color vision deficiency, occurring when one of the three cone pigments is altered in its spectral sensitivity. This results in an impairment, rather than loss, of trichromacy (normal three-dimensional color vision)

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Protanomaly is a mild color vision defect in which an altered spectral sensitivity of red retinal receptors (closer to green receptor response) results in poor red-green hue discrimination. It is hereditary, sex-linked, and present in 1% of all males. It is often passed from mother to child.

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Deuteranomaly, caused by a similar shift in the green retinal receptors, is by far the most common type of color vision deficiency, mildly affecting red-green hue discrimination in 5% of all males. It is hereditary and sex-linked.

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Tritanomaly is a rare, hereditary color vision deficiency affecting blue-yellow hue discrimination.

Resources

Colorvision Testing