The most important role in human life is played not only by the function of vision itself, but also by color perception, i.e. the ability of a person to distinguish colors in different scales. There are cases when there is a violation of color vision. Daltonism is a peculiarity of vision characterized by impaired color perception or its complete absence. Color blindness was first described by John Dalton in the 18th century, who did not see red and did not know about it until he was almost 26 years old.
Fortunately, it would be too much to call this disorder an affliction. These people do not feel the disorder in any way, do not have any complaints. This is, rather, a feature of vision, because it is extremely rare: among men about 8% of the population, and among women - 0.5%. But still colorblind people can experience some difficulties. For example, restrictions in the choice of profession: such people are not allowed to drive vehicles, and they do not become pilots and sailors. A test for color blindness is also mandatory during medical examination at the military enlistment office.
Causes
In the retina of the human eye there are light-sensitive receptors - cones, responsible for distinguishing colors. The absence of one or more cones causes a violation of color perception, which can be detected by the test for color blindness.
Anomaly can be both congenital, transmitted from mother to child, and acquired. Acquired color blindness is extremely rare and occurs due to trauma to the retina or the nerve responsible for visual function, clouding of the lens. It can also be caused by taking certain medications.
Types of color vision
Normal color vision is the ability to distinguish the three primary colors: green, red and violet. It is referred to as trichromasia. Accordingly, people with normal vision are trichromats. Perception of two colors out of three is called dichromasia. The inability to perceive the red pigment is called protanopia, green - deuteranopia, and blue - tritanopia. When only one spectrum of the whole gamut is perceived, monochromasia, or achromasia, is spoken of.
Polychromatic tables E.B. Rabkin - these are special tests-drawings for detecting color blindness in a person. They help to identify whether there is really a disorder of color perception, or it is simulated. Or, on the contrary, to confirm perfect vision with correct perception of the entire color gamut. In addition, the tables are arranged in such a way that it is possible to identify the cause of the anomaly - congenital or acquired.
Tables contain certain drawings consisting of circles of different colors, formed into different figures. The tables are shown in strict sequence and with a clear time interval of 5 seconds. A person who is trichromatic will distinguish all drawings and figures, while a colorblind person does not distinguish tones and sees only blurred images. Moreover, each type of color blindness distinguishes different figures. The study of color vision in children is carried out a little differently: with the help of threads of muline or mosaic, asking the child to disassemble them by color.
How to take the color blindness test online
- The lighting of the screen should be normal, so that no sunlight or glare from the lamp falls on it.
- The screen should be at eye level and at a comfortable distance, but not less than a meter.
- It is necessary to relax and not panic about the possible outcome.
- Do not linger on each picture for longer than 5 seconds.
- If the test revealed any deviations - do not worry. Perhaps the lighting was insufficient or you simply rushed your answer. Take a break and take the test again.
Take our color blindness test
It 's much easier to take the test at home than it is to be checked by a doctor. But if you are not satisfied with the results of the test, or if you are worried about your eyesight, it is recommended to consult an ophthalmologist.
