Daltonism

Daltonism call disturbance of color perception of an eye. On an eye retina, in the central region, called makuly or a macula lutea, the cells responsible for perception and transfer of color are located. Such cells are called flasks. There are three types of flasks, each of which contains one of three types of a pigment – blue, red and yellow. These are primary colors which are perceived by an eye, and all other variety of flowers and shades is formed by mixing blue, red and yellow. The shortcoming or lack of one of pigments causes disturbance of color perception. In most cases disturbances are connected with a lack of a red pigment, is much more rare - blue. Daltonism is not an independent disease, it either congenital anomaly, or a symptom of other diseases of eyes, or some general diseases.

History of discovery of daltonism and interesting facts, related

For the first time this state was described by the English chemist John Dalton in 1794. As hereditary daltonism at children since the birth is shown, they often do not suspect that their perception of flowers differs from color perception of other people. Did not suspect about it and John Dalton until once ordered to itself for an invited dinner an elegant gray camisole. When it came in it to a celebration, suddenly it became clear that other people see its camisole not gray, but bright claret.

John Dalton, as well as his brothers, suffered from disturbance of perception of red color that afterwards in detail described, having given the name to a new ophthalmologic syndrome. Actually the word "suffered" in this case you should not perceive literally as people with inborn daltonism usually do not feel any discomfort connected with the feature as since the birth see the world differently and have no opportunity to compare the image to someone's another.

Daltonism does not prevent the person to perceive the world in its beauty and variety, and does not do it incapable of creativity. The most known example – Mikhail Vrubel's cloths. On the basis of gray scale of his works, researchers of creativity of Vrubel assumed that the artist was the pessimist inclined to a depression. However afterwards it became clear that the artist just did not perceive some colors, being a color-blind person. Nevertheless, this fact did not prevent it to be the ingenious painter who left a bright mark in the history of culture.

Daltonism origins

Daltonism can be inborn and acquired. Cases of the inborn daltonism which is transmitted as the genetic anomaly connected with a female gonosome, and inherited from mother to the son are most frequent. In this case daltonism at children at once, from first years of life is shown, though not always the state is found people around at once. Daltonism occurs at women much less than at men, women participate in transfer of a recessive gene, but, as a rule, have no this defect. However the acquired daltonism at women meets the same frequency, as at men.

The acquired daltonism arises owing to damage of a retina in the field of a macula lutea and diseases of an optic nerve at which the color rendition even on condition of her normal perception is distorted by flasks. Also daltonism can be a symptom of a cataract or diseases of the central nervous system, including damages of a brain.

Symptoms of daltonism

Main and only symptom of daltonism, this disturbance of color perception. Being a sight deviation, daltonism, nevertheless, does not influence neither its sharpness, nor any other characteristics. As it was already mentioned above, daltonism at children can not attract long attention as children take the color perception for granted, and call a grass green even if see this color in a different way. As a rule, parents notice daltonism at children when it is found out that the child does not see a difference between, for example, gray and red, or gray and green color.

The trikhromatiya (from "хромос" – color) is inherent to normal sight when flasks equally well perceive red, blue and yellow color. At full loss from process of one of pigments speak about a dikhromatiya, in the absence of all pigments about an akhromatiya, in this case the person perceives the world, painted in various shades of gray. However a dikhromatiya and the more so, an akhromatiya meet extremely seldom and usually in this case there are also other serious violations of sight, daltonism only one of them. Most often speak about an abnormal trikhromatiya when function of one of pigments is not lost completely, and is reduced.

Diagnosis of daltonism

Disturbance of color perception is diagnosed by means of special polychromatic tables, so-called by Rabkin's tables which use at test for daltonism. They represent the drawings executed by means of points or circles of identical brightness, but differing on color. At usually kept visual acuity, daltonism influences only perception of color, that is noticing brightness degree, color color-blind persons do not notice. Therefore on some tables they do not distinguish the drawing, perceiving the table as the field which is evenly filled with circles or points.

Sometimes in the presence of daltonism cases in a family, the woman, planning conception, wants to find out a possibility of emergence of daltonism in children. In this case genetic test for the daltonism including diagnosis by means of studying of the family anamnesis and also DNA testing is carried out. Genetic test for daltonism of DNA is the high-precision research allowing to define a gene in which there was a mutation and its nature. Unfortunately, opportunities to correct breakdown, even at clarification of the exact reason of defect of a gene, at the moment it is impossible, and similar information has no practical application, and the research is very expensive.

Treatment of daltonism

At the moment there are no effective methods of treatment of daltonism. Attempts of correction of disturbance of color perception by means of the special lenses covered with a special layer which structure allows to change wavelength at perception of some flowers are made. However still these attempts were not too successful, and considerable improvement at use of similar means was not observed.

As inborn daltonism does not progress, the person just studies to adjust perception taking into account the feature, for example, remembering that upper color in the traffic light red, and lower – green. The acquired daltonism demands first of all treatment of that basic disease which caused emergence of a similar symptom.