Improper color perception is a pathological change in visual function and can significantly affect the quality of life. These disorders are observed both congenital and acquired. Consider the features of violations of color perception, their varieties, causes, methods of diagnosis and correction, as well as how this can affect the receipt or replacement of a driverās license.
What is color perception
The human brain is able to distinguish a lot of all kinds of shades. The retina, or rather, cone cells, is responsible for this ability. In a healthy person, color is perceived by three devices that are sensitive to waves of different lengths and radiations. If the eye does not distinguish one color from another, this indicates a violation of color perception.
Pathology can be acquired (in diseases involving the optic nerve or retina) or congenital. In this case, the violations are called color blindness. With such a diagnosis, a driverās license is not issued.
Types of color disturbance
A person who perceives all three primary colors (red, green and blue), that is, uses three apparatuses for their perception, is called trichromat. Pathological changes related to color perception are divided into two main groups.
Congenital disorders usually spread to two eyes at once. Identify them only with the help of a special study. Color blindness does not entail the loss or decline in the quality of other visual functions. Most often, congenital anomalies are inherited. These faces perceive only two colors, but in a slightly different proportion than trichromats.
Types of congenital pathology:
- Deuteranomaly - it is the green tint that is poorly perceived.
- Protanomaly - the red color is almost invisible.
- Tritanomalia - a blue tint is invisible.
- Dichromasia - visual receptors do not perceive one of three shades at all.
- Monochromasia is ācolor blindnessā, that is, a person sees everything only in black and white.
Color pathology is named after the scientist John Dalton, who himself suffered from a violation of perception from childhood.
Acquired disturbances in color perception are most often the result of diseases of the retina, central nervous system, or optic nerve. Pathology can spread to one or both eyes at once.
Types of acquired violations:
- Xantopsia - everything is perceived in yellow.
- Erotropsia is in red.
- Cyanopsia is in blue.
Unlike congenital pathology, which cannot be corrected, acquired abnormalities can be eliminated if the cause of the disease is eliminated.
Color perception is checked with an instrument called an anomaloscope. Drivers and railway workers Transport must pass this study.
Causes and symptoms
As already noted above, the congenital type of violation of color perception is hereditary. Pathology is transmitted from the mother through the X chromosome. Most often, representatives of the stronger sex suffer from color blindness, since they lack the maternal chromosome with such a gene. For a girl to be born with congenital color blindness, it is also necessary for her maternal grandmother to suffer from visual impairment related to the perception of shades.
Acquired pathology can occur for the following reasons:
- Stroke.
- Head injury.
- Cataract or other pathology of visual function in the absence of therapy.
- Diabetes.
- Intoxication of the body.
- Diseases of the nervous system.
The symptoms of color blindness are independent of the type of disorder (congenital or acquired). It lies in the fact that a person cannot distinguish between certain shades, while the visual acuity may not be impaired.
Diagnostics
To determine if a person has a violation of color perception, ophthalmologists conduct a series of studies. The most commonly used polychromatic tables are Fletcher-Gambling, Ishihar, Stilling and others. In the Russian Federation, Rabkin's tests are widely known, which all drivers of vehicles pass.
All methods are the same in principle, presented in the form of drawings of dots or circles of different diameters and shades. If you look closely at the picture, then through the main background you will see a certain picture made in different colors. If a person has a pathology regarding color perception, then he will not consider what is shown in the figure.
Also in ophthalmology, the FALANT test and a device called an anomaloscope are used. It is used to test people when taking them to certain specialties, where it is important to clearly distinguish colors. Using the device, you can diagnose a type of disorder, as well as how a personās color perception is affected by brightness, age, noise, training, medication, that is, visual receptors are examined in a complex.
The FALANT test passes all military persons in America. To do this, you need to determine the color that the lighthouse shows at a certain distance. Those who are color blind do not pass such a test. But 30% of people who have slightly impaired perception can successfully pass the test.
Rabkin Tables
Violations of color perception are allowed when obtaining a driverās license, but only to a small extent. The most common in Russia are Rabkin tests, which consist of 48 tables. They are divided into two groups: the main (27 tables) and control, which are used in case of questions and the need for detailing the visual function.
Rules for testing on Rabkin tests:
- The monitor screen on which each image is displayed should not be too bright or dull.
- All tables should be at eye level. A location higher or lower may affect the accuracy of the test.
- There is a time limit of 5 seconds per image.
As a rule, to check whether a person has color blindness, passing the test in the first 27 pictures is enough. The specialist indicates the diagnosis, as well as the degree of the anomaly (weak, medium or strong).
Violation correction methods
Congenital pathology is not yet correctable, although Western scientists have invented special contact lenses with which color blind people can see the world in different colors. Genetics are also developing methods for introducing genes into the retinal cells that are responsible for the perception of shades.
Congenital inability to distinguish colors does not progress. Since childhood, color blind people memorize colors, and this one does not display in any way on their quality of life.
In order to cure acquired color blindness, it is worth identifying the root cause of the pathology and eliminating it. If the anomaly occurs as a result of age-related changes, it is practically incurable, although when replacing the lens, people have chances to correct the situation. If color perception is caused by the influence of some chemical preparation, you need to cancel it. If the pathology was the result of an injury, it all depends on the degree of destruction of the retina.
Acquired violations of the perception of colors initially appear on one eye, and then spread to the other. At the same time, visual acuity also falls. It is important to identify pathology at the initial stage.
There are no effective (operational or therapeutic) correction methods that would heal violations in the perception of colors. But medicine does not stand still.
Color violation and driver's license
For the first time, people started talking about color blindness and driving a car at the end of the 19th century. In 1975, a major railway accident occurred in Sweden. The culprit turned out to be a driver who could not recognize the red color of the traffic light. After this incident, drivers and railroad workers began to be additionally checked not only for the quality of vision.
Many car owners are interested in the question, is it necessary to replace a driverās license in case of violation of color perception?
In Russia, until 2012, persons with a slight degree of color blindness were allowed to drive a car (category B and C), using it for personal purposes. In 2017, the rules have changed. According to the legislation of the Russian Federation, color blind people are no longer allowed to drive a car. Such a driver poses a serious danger to other road users and pedestrians.
If it is time to replace the rights, a test for the ability to distinguish colors cannot be avoided. In 2018, the chance of getting a driverās license from color blind is minimal. In developed countries, it is permitted to drive a vehicle for those who constantly wear colored contact lenses or glasses. With the help of them, the color blind world becomes colorful, that is, the way the ordinary person sees it.
Is it possible not to pass the test on the Rabkin tables
Great yogis or mahatmas about the violation of color perception said that these are special people. Unfortunately, such car owners cannot pass the test for the ability to distinguish colors successfully. Theoretically, you can memorize all the pictures. But the doctor may show them out of order, which greatly reduces the chances of success.
Some believe that you can always agree with an ophthalmologist. But in this case it is worth assessing whether such a risk is really justified. Indeed, not only other road users, but the driver himself may be at risk. If you do not distinguish how the colors change at the traffic lights, you should not drive.
Conclusion
Persons with color impairment lead a completely normal lifestyle, with the exception of some discomfort. Color blind people are somewhat limited in their choice of profession; they cannot become military. Also, since 2017, car owners with color blindness have practically no chance to get a driverās license.
Reviews
People with color blindness write on forums that this doesnāt interfere with their life at all. They are used to seeing the world a bit different, but they find nothing wrong with that. Only those who could not pass the Rabkin test and get a driverās license are lamented.
Some people write that they perfectly distinguish all colors (as it seems to them), but during the test they couldnāt name the numbers in all 27 pictures.
About corrective color sensation glasses reviews, mostly positive. Users note that with their help you can really see the world in a slightly different way. Branded glasses cost from 18,000 rubles, which is very expensive for some. But you can buy cheaper Chinese counterparts. They work too.