Colorblindness

December 19, 2011

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Colorblindness   - Is a condition that develops in humans due to the lack of cells of the retina, which are sensitive to the color, or due to a failure in their work. Retinal layer called nerves located in the posterior part of the eye. These nerves are responsible for converting light into nerve signals, which in turn sends information to the brain. Those who are colorblind, manifests rejection of certain colors. Typically, this red . blue . green   color or their various combinations. The disease got its name from the English study by John Dalton, who described in 1794 by a certain kind of color Blindness Guided by their feelings. After all, he did not distinguish Dalton red, had a similar disease and two of his brothers. However, scientists realized that not only sees red when he was twenty-six years.

Typically, the eye has three types of cone cells   ( tapered cone ). They are located in the retina and are sensitive to light. Each of the three types of sensitivity to certain colors - red, blue, green. Accordingly, people can see colors, its cone cells determine the number of cells these three primary colors. If you are missing one or more of these types of cells, or they are not working properly, then the person does not see a particular color, or even distinguish it in a modified form.

Basically cone cells are concentrated on the center of the retina, thus providing, bright color vision. These cells are the most quality in good light, so the dim light of the distinction between colors becomes more difficult.

Color blindness is also called " color vision problems "Because most people who are diagnosed with color blindness, still partially distinguish colors. However, many people with color blindness generally can not distinguish colors.

Causes of color blindness

Problems of that, one way or another, related to the perception of colors, are mainly genetic and, accordingly, there is a person from birth. At the same time, problems with vision otherwise provoke human aging, disease, eye injuries, as well as the side effects of certain medications. Problems of hereditary nature, relating to the definition of color are more frequent than the disease acquired. Most often they occur in males.

Diagnosing colorblindness

To diagnose the disease, used specially developed tests for color blindness. Today, the most well-known test for color blindness - it pseudoisochromatic test plate. The essence of the test is that the patient take a look at a set of points defined colors and see which letter or number where indicated. According to how people perceive patterns or not accept, the expert is easy to determine what type of color vision problem occurs in a patient. During the test, using several different plates.

For those who are assumed to be acquired color vision problems, it is proposed to go a test for color blindness Which is based on the distribution of objects in color. The test involved the distribution of different subjects, given their color or shade. Patients who are color blind will not be able to pass this test, properly arrange all the colored plates.

Symptoms of color blindness

Similar problems directly alter the overall quality of life. Wrong perception of colors not only effect on the process of learning, reading, and then narrow the opportunities for professional choice of the person. But with the right approach, and children and adult patients can compensate for its own inability to distinguish between certain colors.

Over time, the symptoms of color blindness can vary. So, different people can see different shades of colors. People with color blindness does not distinguish between red, green and blue colors. Those with less serious problems, visible blue or yellow. In the most serious disorders of color vision people are generally not able to distinguish colors. They see the world only in black and white colors, with different shades of gray.

Vision problems are characteristic of a hereditary nature at the same time for both eyes. At the same time, acquired problems of this nature may occur only in one eye. They can affect one eye more strongly than the other.

Inherited color vision pathology mainly occur at birth, and over time, they do not change. But problems can vary acquired or aggravated over time, with age or due to a specific disease.

Types of inherited color blindness

The most common problems with eyesight hereditary nature of a pathology in which a person does not distinguish between a hard distinguish red or green color. Such vision defects occur in about 8% of men and much smaller - 1% - the number of women. It is very rare in women and men have the problem of color vision, when the patient distinguish between blue and yellow colors the same way.

Total to distinguish between four main types of inherited color vision problems:

Abnormal trihromasiya   - It is the most widespread pathology of color vision. It occurs in people who have three types of cone cones, but one type of cone cone is missing or has a lack of pigment for color perception. Those who suffer such disorders, see all the colors, but some - green, red and blue - they see in other colors than people who are not suffering from disorders of color perception.

Dihromasiya   - A problem that manifests itself in the absence of one of the three types of cones of the cone. In view of this, one sees only two of the three basic colors. Most patients dihromasiey, there is no problem with the definition of the difference between blue and yellow flowers. However, the difference between red and green so people have a lot more complicated. When diagnosing problems, it is important to take into account that very few patients with dihromasiey well distinguish red and green, but the confused blue and yellow colors. This type of disease is considered more serious than anomalous trihromasiya.

Blue Cone monohromasiya   - Is a pathology in which no two cones cone - red and green. This type of disease is manifested exclusively in males. People with such disorders have difficulty seeing at a distance, and boys at a young age are sometimes observed involuntary eye movements (this is called nystagmus ). From the whole color spectrum are people with such disorders are distinguished only blue color and its shades.

Achromatopsia - Last, the fourth type of inherited color vision disturbances. In this case the person absent three types of cones of the cone. When a person sees this pathology only shades of black, white and gray. Patients who suffer from this type of diseases often diagnosed and other diseases of view. So, they have plenty of blurred vision when reading, they do not see in the distance. It manifested and high sensitivity to light. This is a violation of the most rarely seen type of color issues, but the most serious of all types. Another name for this disease - monohromasiya retinal rods .

Almost all color vision problems are directly related to regulating the production of pigments in the cone cones genes. These genes, which are responsible for the perception of the man in red and green, located in the X chromosome. Accordingly, the two X chromosomes in women there, and only one - the representatives of the male sex. For example, a man will appear a problem of perception of red and green if the defective gene is located in the X chromosome it. Women like gene may be in any of the two X chromosomes. It also causes problems with the perception of colors, but this is much less common. Also, carriers of the gene have a 50% chance of passing the gene sons. But the daughters of a woman like vision problems may occur only in the case of inheritance by her defective gene from both parents. Of course, this case is less likely.

In families where there is a hereditary predisposition to the appearance of color vision problems, such as abnormal phenomena may occur even after several generations.

Genes that are responsible for pigment retinal cones and blue color perception, are not in the X chromosome, and non-sexual chromosome, which is the people of both sexes. Therefore misperception blue occur in both men and women. But while these color vision problems occur infrequently in general.

Acquired color blindness

Causes of acquired problems with color vision may be a number of different manifestations. So, this pathology can occur with age-related changes, when a person takes a darkening of the lens. As a result of this process, people are hard to distinguish dark blue, dark green and dark gray color. It happens that the violation of color perception is manifested due to the side effects of certain medications. Such diseases can be either temporary or permanent. A number of eye diseases that often occur in people of any age, can provoke the manifestation of color visual impairment. Thus, the development of these problems can cause glaucoma . cataract . macular degeneration . diabetic retinopathy . Restoration of quality is possible with proper treatment of the mentioned diseases. Also, similar problems may provoke eye injuries, especially the retina. Acquired color blindness occurs with equal frequency in men and women. When such problems as color blindness may occur in one eye and the other thus can well distinguish all colors and shades.

Color Blindness Treatment

Unfortunately, problems with color vision hereditary nature are not amenable to correction or treatment. At the same time, problems of the type acquired in some cases to treat. However, in this case, an important cause of disease. So, if there are problems with color perception arose as a result of cataract, after its removal of color vision can be completely back to normal.

People with hereditary color blindness mild over time produced persistent habit to associate a color with a certain subject and thus define a particular color in everyday life. Today, color-blind with some forms of the disease offer to wear special glasses proportion of color correction. However, they can only correct perception of certain colors.

Color blindness is a stumbling block for training and follow-up work in some areas. Thus, the color-blind can not be firemen, machinists, electricians, pilots, doctors and others. Also, a person with color blindness can not get a driver's license.