Color blindness is called impaired color perception of the eye. In the retina, in the central area, called the macula or yellow spot, are the cells responsible for perception and color reproduction. Such cells are called cones. There are three types of cones, each of which contains one of the three kinds of pigment - blue, red and yellow. These are the basic colors that the eye perceives, and everything else a variety of colors and shades formed by mixing blue, red and yellow. The lack or absence of one of the pigments is a violation of color. In most cases, violations related to the lack of red pigment, much more rarely - blue. Blindness is not a separate disease, it is a congenital anomaly or a symptom of other diseases of the eye, or some of the common diseases.
History of the discovery of color blindness and interesting facts associated with it
For the first time it is able to describe the English chemist John Dalton in 1794 As shown hereditary blindness in children from birth, they are often not aware that their color perception is different from the other people of color. I do not know it, and John Dalton, until he ordered a dinner party for elegant gray coat. When he came to it a celebration suddenly turned out that other people see it is not a gray coat and a bright maroon.
John Dalton, as well as his brothers, suffered a violation of the perception of red, which later described in detail, giving the name of the new ophthalmic syndrome. In fact, the word "suffered" in this case should not be taken literally, since people with congenital color blindness usually do not experience any discomfort associated with a special feature, since the birth of seeing the world differently, and have no opportunity to compare his vision with someone else.
Color blindness does not prevent a person to perceive the world in its beauty and diversity, and makes him unable to work. The most famous example - paintings of Mikhail Vrubel. On the basis of the gray scale of his works, the researchers creativity Vrubel assumed that the artist was pessimistic, prone to depression. However, it later became clear that the artist simply did not take some of the colors being color-blind. However, this fact does not prevent him from being a painter of genius, left a bright trace in the history of culture.
Causes of color blindness
Color blindness can be congenital or acquired. The most frequent cases of congenital color blindness, is transmitted as a genetic anomaly associated with the female sex chromosome, inherited from the mother and the son. In this case, it appears blindness in children right from the first years of life, although not always immediately detected around the state. Color blindness in women is much rarer than men, women are involved in the transmission of a recessive gene, but they usually do not have this defect. However acquired blindness in women occur with the same frequency as men.
Acquired color blindness is caused by lesions of the retina in the macula and optic nerve disease in which the distorted color reproduction even if its normal perception cones. Also color blindness may be a sign of cataract or disorders of the central nervous system, including brain lesions.
Symptoms of color blindness
The main and the only sign of color blindness, impaired color perception is. As the deviation view, blindness, however, affects neither its acuteness, or to any other characteristic. As mentioned above, the color-blindness in children may be a long time not to pay attention, because children perceive their color perception for granted, and called the green grass, even if they see the color differently. As a rule, blindness in children parents notice when it is found that the child does not know the difference between, for example, gray and red, or gray and green.
Normal vision is peculiar trichromats (from "Chromos" - color), when the cones equally well perceive the red, blue and yellow. With the full loss of the process of one of the pigments suggests dichromate, in the absence of an achromatic pigments, in this case, a person perceives the world, painted in different shades of gray. However, dichromate, and the more achromatic are extremely rare and are usually present in this case and other serious visual impairment, blindness, only one of them. Most often talk about abnormal trichromats the function of one of the pigments is not lost completely, but reduced.
Violation of color are diagnosed with special polychromatic table, so called table Rabkin, which are used for carrying out the test for color blindness. They are drawings made by using dots or circles of equal brightness, but different in color. If you usually stored visual acuity, color blindness affects only the perception of color, that is, observing the degree of brightness, color, color blind not to notice. Therefore, some tables, they do not distinguish between drawing, perceiving the table as evenly filled circles or dots field.
Sometimes, in the cases of color blindness in the family, a woman planning to conceive, wants to find out the possibility of color blindness in children. In this case, a genetic test for color blindness, including the diagnosis by examining family history and DNA testing. The genetic test for color blindness DNA - a precision study that indicates a gene in which a mutation has occurred and its nature. Unfortunately, the opportunity to correct the damage, even if the exact cause of the defect gene is not currently possible, and such information is of no practical use, as the study itself is very expensive.
Color Blindness Treatment
At the moment, there is no more or less effective treatments for color blindness. Attempts of color correction of violations using special lenses, a special coated layer, the composition of which allows you to change the wavelength of the perception of some colors. But so far, these attempts were not very successful, and a significant improvement in the application of these funds was not observed.
Since congenital color blindness is not progressing, one simply learns to correct the perception based on their characteristics, for example, remembering that the top color of the traffic lights in red and the bottom - green. Acquired color blindness is primarily requires treatment of the underlying disease that caused the appearance of these symptoms.