Даже если вы никогда не встречали человека, unable to distinguish any colors, it must be said that color blindness is a fairly common disease of modern times. Among the inhabitants of the planet can be color blind, not only people. Many animals are "owners" of color blindness. For example, the bulls are not at all familiar with the color red, but with menacing predators like lions and tigers, only blue and green are known. Similarly perceive the colors of cats and dogs. Walruses, whales and dolphins do not distinguish colors in general and see the world around them in black and white.
Why not all colors are available to the eye?
The retina of the human eye is complex,multifactorial instrument of the organ of vision, which transforms the light stimulus and allows you to see the object in its exact form and with all shades of color. It is equipped with photosensitive cones containing a pigment responsible for determining color. A person has three types of light sensors located on the retina, the so-called cones. Each one contains a specific set of protein pigments. Speaking in an unscientific language, each of these cones is responsible for the perception of a particular color: red, green, and blue. In the case when one of the set of protein pigments is missing, the person loses the ability to perceive a certain color. In the normal operation of all three sensors, a person distinguishes about a million shades of color, but with two, only 10,000 (100 times less). Color blindness is a deviation from the norm when the work of at least one light sensor is disrupted.
People with color blindness are hardlyperceive shades, but can recognize colors by brightness or tones, cold or warm. Color blind people do not always know about their disease and do not notice their differences in perception from the sensations of other people. This helps them to memory. It is the memory and brightness of the image that allows them to judge a particular color and compare it with another palette.
Types of color blindness
Color blindness also has many varieties. Sometimes a person has less than three color cones since birth. From here and groups of people on perception of color:
• Trichromates (normal, all three flasks of protein pigments function in the retina).
• Dichromates (only two cones are functioning; problems arise with the recognition of many shades).
It is this deviation that John has identified.Dalton, an English naturalist, and the first to describe color blindness on his own feelings from a scientific point of view. He just belonged to the group of dichromates, when the red and green colors are seen as different shades of brown-yellow color. The first work on color blindness D. Dalton was written at the end of the XVIII century.
• Monochromats (only one type of cones functions; in this case, the test for color blindness will show that people do not know about flowers, the whole world is black and white for them).
Abnormal trichromats
There are abnormalities in people whose retinathe eyes are equipped with all three light sensors, and it would seem that all colors should be perceived. The problem may lie in the so-called color failures. The fact is that, ideally, the sensitivity zones of light sensors of the eye, which are responsible for the perception of a particular color, should overlap each other, always evenly. This allows the eye to perceive all shades from one color to another: from blue to green, from green to yellow, from yellow to orange and beyond. When the sensitivity zones shift (overlap one another), they begin to argue, the shades become layered, the pure colors dim. The brain becomes confused and begins to define certain colors as simply gray. This is called abnormal tricolor vision.
Color blindness innate
Partial or complete inability to distinguish colors is a hereditary or acquired pathology (it occurs much less often).
Hereditary Daltonism is a recessive sign of inheritance associated with the pathology of the X chromosome; therefore, more often the disease is inherited from the mother boys.
As is known, the female embryo is a carrier of twoX chromosome. But for a normal perception of color, one healthy X chromosome will suffice. For girls, the disease spreads only when both mother and father suffer from color blindness. But even in this case, according to the laws of genetics, color blindness in women who have only one chromosome with an affected gene, which does not appear in the host, can be inherited by the son. But this does not necessarily happen. The gene for color blindness can be transmitted even after several generations. Again, the male population is more likely to be at risk.
По статистике, дальтонизм у женщин фиксируется only in 0.1% of cases. Among men, 8% are color blind. With the hereditary factor, color blindness is, as a rule, a pathology of both eyes that does not progress with time.
Color blindness acquired
The main factors affecting the acquisitioncolor blindness, always directly or indirectly associated with either brain injuries or retinal damage. Sometimes a concussion in childhood can later affect color perception. In addition to childhood injuries, other factors can influence the acquisition of color blindness:
- Old age.
- Eye damage due to injury.
- Concomitant eye diseases (glaucoma, cataracts, etc.).
- Drugs that have a side effect.
Diagnosis of color blindness. Testing
Дальтонизм – это данность, которую нужно просто to accept. He is not treated. This is the same as a musical ear: someone has it, and someone does not. Never need to do self-diagnosis. If you notice a deviation in the perception of color in yourself or your children, you need to contact a specialist. There are proven methods for determining color blindness and its type.
1. Rabkin test (polychromatic tables).
Проверка на дальтонизм в этом тестировании produced by viewing the tables in which various numbers or letters are depicted. Readable images are applied using color spots that are the same in contrast and brightness. The result of the test will be the ability of the subject to recognize the desired numbers or letters in the images.
2. Test Ishihara.
A similar test in the form of tables, allowing morepinpoint a moderate, strong degree of color blindness and complete color blindness. There is a complete edition of this test from 38 tables. They are used by professional ophthalmologists.
A shortened version of 24 tables is used forrapid testing for the recruitment of municipal institutions, airports. There is also a short specialized publication of 10 tables for preschoolers and illiterate people. Instead of letters and numbers in these tables, images of geometric shapes and various lines are used.
Color Blindness and the Human Profession
Ограничения, с которыми может быть связан выбор professions are color blind, very important. First of all, these restrictions apply to professions where there is responsibility for life, one’s own life or other people. Color blind people are not accepted for military service; they cannot be pilots of aircraft, drivers of commercial vehicles and chemists. For these professions are required annual medical examinations, which are admission to the professional activity. If a person on examination revealed color blindness, the rights in his profession are sharply reduced. He may be engaged in theoretical training of young professionals, to perform office work related to their professional skills.
Color Blindness and Driving License
If in some professions color blindness is a sentence, then for obtaining a driver's license the restrictions do not apply to everyone. Here the opinion of a specialist is important.
Driving license and color blindness - the concept is quitecompatible, but only after the conclusion of an ophthalmologist. Only the doctor determines the type and degree of color blindness, therefore, and gives permission to the patient to drive a private car. Color blind people can get the rights of categories "A" and "B", in which there must be a mark "Without the right to work for hire."
To help color blind
Ученые регулярно предлагают новые медицинские "Gadgets" that can alleviate the plight of people with disabilities. It turns out, despite the fact that doctors can not fix cones-sensors, it became possible to reprogram the brain to the correct color perception. Today, special glasses have appeared, in which narrow spectral strips are simply “cut out” by lenses and pure colors are separated from each other. The principle of enhancing the contrast allows the red, blue and green colors to not mix.
Science has helped many color blind people to see colors of which they didn’t even suspect: purple, bright green and bright red.
