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Color Blindness

There are some unlucky people who get this disease. As they said, the eyes are the mirror of our soul. We should know how to keep our eyes healthy. Here you are, we give you information about color blindness.

Color blindness is an abnormal condition characterized by the inability to clearly distinguish different colors of the spectrum. The difficulties can range from mild to severe. It is a misleading term because people with color blindness are not blind. Rather, they tend to see colors in a limited range of hues; a rare few may not see colors at all.


Most color blindness is inherited. Less frequently, color blindness is caused by a disease affecting the optic nerve or retina. This is referred to as “acquired color blindness.”

A. By Cause
Color vision deficiencies can be classified as acquired or inherited.

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

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.

>>>Rod monochromacy (achromatopsia) is an exceedingly rare, nonprogressive inability to distinguish any colors as a result of absent or non functioning retinal cones. It is associated with light sensitivity (photophobia), involuntary eye oscillations (nystagmus), and poor vision.

>>>Cone monochromacy is a rare total color blindness that is accompanied by relatively normal vision, electoretinogram, and electrooculogram.

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, in the case of Protanopia or Deuteranopia, sex-linked, affecting predominantly males. Dichromacy occurs when one of the cone pigments is missing and color is reduced to two dimensions.

>>>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 males.

>>>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 and sex-linked.

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

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).

>>>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 males.

>>>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 males. It is hereditary and sex-linked.

>>>Tritanomaly is a rare, hereditary color vision deficiency affecting blue–yellow hue discrimination. Unlike most other forms, it is not sex-linked.

B. By clinical appearance

Based on clinical appearance, color blindness may be described as total or partial. Total color blindness is much less common than partial color blindness. There are two major types of color blindness: those who have difficulty distinguishing between red and green, and those who have difficulty distinguishing between blue and yellow.

* Total color blindness
* Partial color blindness
* Red–green
# Dichromacy (protanopia and deuteranopia)
# Anomalous trichromacy (protanomaly and deuteranomaly)
* Blue–yellow
# Dichromacy (tritanopia)
# Anomalous trichromacy (tritanomaly)


There is no cure for inherited color blindness; however, most people with color blindness learn to distinguish between colors accurately and easily.

Talk with your doctor about coping skills. Additionally, depending on the level of color blindness, some doctors recommend using color-corrective glasses or contact lenses.

In some cases of acquired color blindness or deficiency, such as those caused by cataracts or another disease, treatment of the cataract or other medical problem may correct the color blindness, as well.

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