Impaired color vision: vision test for color perception, possible causes and how to correct color vision. Violation of color perception: causes, types and description, methods of correction, reviews

Anomaly of color vision is extremely rare and is more often a hereditary pathology. The disease does not affect the quality of life in many ways, except for driving a car.

Violation of color vision is most often a congenital disease. Pathology is transmitted from parents to children, from birth the child suffers from impaired color perception. The disease affects in most cases men, which is associated with the peculiarities of the inheritance of pathology. It is transmitted to the child from the mother through the X chromosome if the mother is a carrier of the disease. Parents can pass on pathology to their daughters only if the father suffers from a violation of color vision, and the mother is a carrier of this disease.

Less often, an anomaly of color perception develops as an acquired pathology. The main reasons are:

eye injury;
eye diseases;
diseases of the nervous apparatus of the eye;
diabetes.

The most common cause of acquired color vision anomaly is diabetes mellitus, more precisely its complication is diabetic retinopathy. It is a lesion of the vessels of the eye, due to an increased level of glucose in the blood. Therefore, a person with type 1 or type 2 diabetes is at risk for color vision anomalies.

Among eye diseases that lead to a violation of the perception of colors, cataracts are in the first place. This pathology is a clouding of the lens. The lens in the eye plays the role of a kind of lens through which light rays pass. Normally it is transparent. But with age, the lens begins to become cloudy, which leads to a violation of the perception of colors. Therefore, all elderly people are at risk of this pathology.

A separate group of causes are medications. There are drugs that can affect the human visual apparatus. These drugs include:

digoxin.
amiodarone.
erythromycin.

Therefore, if the perception of colors is suddenly disturbed while taking these medications, it is necessary to exclude medications as the cause.

Also, before taking these drugs, you should definitely consult a doctor and, in case of a side effect, immediately seek medical help.

Symptoms

There are several types of color vision anomalies:

monochromasia;
dichromasia;
trichromasia.

Monochromasia is characterized by a violation of the perception of all colors, since there is a violation in all pigment layers of the eye. As a result, a person sees only black and white pictures. With this form, if the function of the cones is impaired, in the patient all colors are represented by one color tone. If the disturbance is in sticks, the patient perceives everything in gray, but in its various shades. This type of color perception anomaly is extremely rare.

Dichromatic vision is characterized by abnormalities in one of the three pigment layers of the eye. A synonym for dichromacy is color blindness, since a scientist with the surname Dalton first described such an anomaly in color perception.

There are several varieties of dichromatic vision:

protanopia.
deuteranopia.
tritanopia.

The types of color perception anomalies are divided depending on what color the human visual apparatus is not able to perceive. With protanopia, the patient ceases to perceive the color red. Deuteranopes cannot see green, and tritanopia is blind to blue.

There is a classification of protanomaly and deuteranomaly depending on the severity. Grade A is characterized by a sharp severity of clinical manifestations. Protanomaly type B is considered to be of moderate severity. Protanomaly type C is the mildest degree of manifestation. It is similar to the normal tricolor perception of colors. The same applies to deuteranomaly type C, in which the impaired perception of green is extremely weak.

With trichromacy, the function of all three pigment layers is preserved, a person is able to perceive all colors, but the perception of any of the colors is slightly impaired. Trichromasia is close to normal vision, but the colors in it are perceived more dull. This condition is called anomalous trichromasia.

Normal human vision is also called trichromacy. But unlike anomalous, with normal trichromasia, the perception of absolutely all colors is preserved.

Color anomaly is most often an independent pathology, which is not accompanied by any other symptoms, except for impaired perception of colors. But in some cases, the disease can be caused by cataracts or diabetes. In such cases, in addition to the color anomaly, a number of symptoms of these diseases are added.

Diagnostics

Many patients may not complain about impaired color perception for a long time. In such cases, the pathology is diagnosed during the study of color vision at medical examinations.

Deviations in color perception can be diagnosed using Rabkin's tables, which are pictures made up of circles of different colors. In each such picture, a geometric figure or number is encrypted. There are tables where both the figure and the number are depicted at the same time. A person with normal vision on each of the tables is able to distinguish what is encrypted. A person with color blindness will either not be able to distinguish, or will name the wrong figure.

In total, there are 48 pictures for determining color anomalies, which are divided into two groups. The first group includes the main tables, thanks to which the main types of color perception disorders are diagnosed. The second group is the control group. It is necessary to exclude the simulation of the patient.

During the study, the patient should be with his back to the light source. The tables in front of him should be placed vertically at a distance of 0.5-1 meter from the eyes. If the tables lie on the table, the method for determining color perception is violated and a false result is possible.

When examining color vision, the patient must give an answer within 5-10 seconds - what he sees on the table. All answers are entered in a special form, after which the result is compared with a special table and the final diagnosis is made.

The diagnosis of color perception anomalies can only be made by an ophthalmologist.

Treatment

It is impossible to completely cure impaired color perception. Treatment of color anomaly is aimed at reducing the severity of symptoms and correcting visual acuity. Also, treatment is carried out in order to stop the pathological process. In the absence of adequate therapy, a person can completely lose his sight.

Contact lenses or glasses are used to normalize visual acuity. They are recommended to be worn by all patients with impaired color perception. In order to correct the perception of colors, there are tinted glasses and lenses with pigments. In the sun, patients are advised to go out only in sunglasses.

In the case of an acquired anomaly of color perception, when the cause of this condition is established, the question of surgical correction may be decided. The operation can be performed on the affected area of the eye or on the part of the nervous system that is responsible for the susceptibility to colors. In the presence of a cataract, an operation is indicated to remove it.

The complex therapy of impaired color perception includes vitamins. All patients are shown taking vitamin complexes with a high content of vitamins A and E.

If the disease has arisen as a complication of diabetes mellitus, the patient is recommended appropriate treatment by an endocrinologist.

Violation of the perception of colors and driver's license

All people who want to drive a car are required to be examined by an optometrist. It includes, in addition to the study of visual acuity and visual fields, the definition of color perception.

All people with impaired color perception are not allowed to drive. People with color blindness are capable of causing emergency situations, so this issue should be taken seriously at the medical board.

Prevention

In order to prevent the occurrence of color blindness in a child, parents are advised to undergo medical genetic counseling before pregnancy. If a person already has an anomaly in color perception, he should be registered at the dispensary and regularly visit an ophthalmologist to monitor and correct treatment.

Color perception (color vision)- the ability of the eye to perceive colors based on sensitivity to different ranges of radiation in the visible spectrum. This is a function of the cone apparatus of the retina.

All colors are divided into two groups:

BUT) Chromatic- all tones and shades of the color spectrum. Chromatic colors are characterized by three qualities: 1) hue 2) saturation 3) brightness.

B) achromatic- white, gray, black colors, in which the human eye distinguishes up to 300 different shades. All achromatic colors are characterized by brightness, i.e., the degree of proximity to white.

depending From the wavelength three groups of colors can be distinguished:

A) longwave (red, orange - "Every hunter")

B) medium wave (yellow, green - "... wants to know")

C) shortwave (blue, blue, purple - "... where the pheasant sits")

The whole variety of color shades (several tens of thousands) can be obtained by mixing the three main ones - red, green and blue.

According to Three-component theory of Young-Lomonosov-Helmholtz And, there are three main types of cones, each of which has a specific pigment that is selectively stimulated by monochromatic radiation.

1) blue cones - maximum spectral sensitivity in the range of 430-468 nm

2) green cones - maximum spectral sensitivity at 530 nm

3) red cones - maximum spectral sensitivity at 560 nm

Color perception is the result of the action of light on all three types of cones. Radiation of any wavelength excites all the cones of the retina, but to varying degrees. With the same stimulation of all three groups of cones, a sensation of white color occurs.

Allocate congenital and acquired disorders of color perception. They are always bilateral, are not accompanied by a violation of other visual functions, are detected during a special study.

Congenital disorders of color perception may either appear

1) Abnormal color perception- color anomaly (abnormal trichromasia, maybe protanomaly - abnormal perception of red, deuteranomaly - green, tritanomaly - blue)

2) Complete loss of one of the three components(dichromasia, maybe protanopia - non-perception of red, deuteranopia - green, tritanopia - blue) or only

3) Black and white perception (monochromasia).

Congenital blindness to red color blindness.

Acquired disorders of color perception occur in diseases of the retina, optic nerve and central nervous system. They occur in one or both eyes, are expressed in a violation of the perception of all three colors, are usually accompanied by a disorder of other visual functions, unlike congenital disorders, they can undergo changes in the course of the disease and its treatment.

To Acquired disorders color perception refers to the vision of objects painted in any one color. Depending on the tone of the color, there are:

A) erythropsia - in red

B) xanthopsia - in yellow

C) chloropsia - in green

D) cyanopsia - in blue.

Assessment of the color discrimination ability of the eye:

1. Rabkin's special pigment polychromatic tables- made up of circles of different colors, but the same brightness. Circles of one color make up a figure or number painted in a different color against the background of other circles. The doctor holds the table in front of the patient's eyes at a distance of 0.5-1 m for 5 seconds. Trichromats see a figure (figure), while dichromats do not.

2. spectral instruments - Anomaloscopes. The action of anomaloscopes is based on a comparison of two-color fields, of which one is constantly illuminated by monochromatic yellow rays with variable brightness (control field), and the other, illuminated by red and green rays, can change tone from pure red to pure green. Mixing red and green colors, the subjects should get a pure yellow color, corresponding to the control.

A vision test for color perception for drivers is carried out during a medical examination under the guidance of an ophthalmologist. Human vision perceives information. Color perception is an important point.

Most often, this concept is encountered by people when passing a medical commission to obtain a driver's license.

Medical examination of drivers is mandatory for all without exception. The law provides for the procedure and rules for its implementation.

The conclusion of an ophthalmologist is issued on the basis of an eye examination in the following areas:

Sharpness.
Color perception.

With an understanding of the process of checking visual acuity, as a rule, there are no questions. Regarding the point of checking for color perception, clarifications and clarifications, drivers preparing for the inspection will need it.

The color perception of a person is determined by heredity. In the central part of the retina of a healthy patient, there are nerve receptors sensitive to color, the so-called cones. Each cone contains pigments of protein origin. There are only three such pigments.

The absence of any of the three color-sensitive pigments is considered a deviation and entails a violation of color perception.

The task of the specialist conducting the examination is to determine the norm or to identify anomalies in color perception. For these purposes, testing is carried out.

According to the test results, the types of color vision are accurately identified:

The normal type is trichromat. All three pigments (red, green and blue) are present.
Anomalous type - dichromate. Only two of the three possible pigments are present.
Anomalous type - achromat. The complete absence of color-sensitive pigments.

Why is this check necessary?

Incorrect color perception or color blindness makes it difficult, and sometimes completely excludes the opportunity to engage in a certain type of activity for a particular person. Color blindness is often the reason for dismissal from duties, where color perception is the main and integral part of the work.

Drivers of vehicles fall into this category. The driver is obliged to respond correctly to color signals, as this is directly related to road safety. Traffic signals and road signs are not perceived properly.

A transport worker's color blindness caused a train derailment in 1975 in Sweden. This event marked the beginning of research in this direction, and the first test for color blindness for transport workers was developed.

But during the life and professional activities of some people, it may change. Therefore, checking by an ophthalmologist for color perception, as well as visual acuity, is mandatory and involves a certain frequency (medical examinations).

When is a Color Vision Test Performed?

Color perception is an important component of healthy vision, the key to the correct reaction of a person to surrounding circumstances and an adequate assessment of reality, which is so necessary when driving.

When passing a medical examination, each driver is required to visit an ophthalmologist. The specialist examines the parameters of vision, including, in addition to its sharpness, a test for color perception.

In addition to the mandatory assessment of the state of color perception, the conditions for its implementation are considered an important point.

To obtain the correct result of the color perception test, certain rules must be observed:

Natural lighting in the room (do not test under artificial lighting).
The state of health of the researcher should be normal, rested.
There should be no direct sunlight.
Test tasks should be located at a distance of 1 meter in a strictly vertical position.
Time for each image is given no more than a few seconds.

Thus, if you are going to drive a vehicle or your professional activity is directly related to the recognition of color signals, then you will have to pass a color perception test.

With age, it may also be necessary to conduct a similar diagnosis, as your vision parameters change.

In case of injuries of various nature affecting the visual apparatus, an ophthalmologist specialist will observe and track trends in your color perception through testing.

Rabkin's table - what is it, the principle of operation

A simple diagnostic method for detecting abnormal vision is the spectral method.

Rabkin's tables help to determine and accurately differentiate three forms of deviation in color perception:

deuteranomaly - a violation of the perception of the green spectrum;
protanomaly - impaired perception of the red spectrum
tritanomaly is a violation of the perception of blue.

In each of the anomalies, three degrees are determined:

A - strong;
B - medium;
S is easy.

With color blindness, partial or complete absence of color perception, the test person does not distinguish between individual colors and sees a uniform pattern. While each image consists of a large number of multi-colored circles and dots of the same brightness, but differing in color.

Rabkin's table - for color perception with answers

The Rabkin table test for color perception makes it possible to identify the form and degree of color blindness.

Test and answers:

norm (type trichromate) - 96;
protanomal-96;
deuteranomal - 96.

The table demonstrates the testing method, has a special meaning and is a control. It is necessary to understand the principle of passing the test. That is, the picture is equally seen by people with normal color perception and color blind people.

norm (type trichromate) - triangle and circle;
protanomal - triangle and circle;
deuteranomal - triangle and circle.

The image helps reveal the simulation. The picture is perceived identically by each group of subjects.

norm (type trichromate) - 9;
protanomal-5;
deuteranomal - 5.

norm (type trichromate) -triangle;
protanomal-circle;
deuteranomal - circle.

norm (type trichromate) - 13;
protanomal-6;
deuteranomal - 6.

norm (type trichromate) - circle and triangle;
protanomal - does not perceive;
deuteranomal - does not perceive.

norm (type trichromate) - 96;
protanomal-96;
deuteranomal - 6.

norm (type trichromate) -5;
protanomal–-;
deuteranomal– -.

norm (type trichromate) -9;
protanomal-6 or 8;
deuteranomal - 9.

norm (type trichromate) -136;
protanomal-66, 68 or 69;
deuteranomal - 66, 68 or 69.

protanomal-triangle;
deuteranomal - circle/circle and triangle.

norm (type trichromate) -12;
protanomal-12;
deuteranomal– -.

norm (type trichromate) – triangle and circle;
protanomal-circle;
deuteranomal is a triangle.

norm (type trichromate) -30;
protanomal-10, 6;
deuteranomal - 1, 6.

norm (type trichromate) - on the right is a triangle, on the left is a circle;
protanomal - two triangles at the top, a square at the bottom;
deuteranomal - triangle at the top left, square at the bottom.

norm (type trichromate) -96;
protanomal-9;
deuteranomal - 6.

norm (trichromate type) - a triangle and a circle;
protanomal-triangle;
deuteranomal - circle.

norm (trichromate type) - horizontally eight single-color squares, vertically multi-colored squares;
protanomal - vertically one-color squares in the 3rd, 5th, 7th row, horizontally colored squares;
deuteranomal - vertically one-color squares in the 1st, 2nd, 4th, 6th, 8th row, horizontally colored squares.

norm (type trichromate) -95;
protanomal-5;
deuteranomal - 5.

norm (type trichromate) - circle and triangle;
protanomal - nothing;
deuteranomal - nothing.

norm (trichromate) - vertical six one-color squares, horizontal multi-colored rows.

norm (trichromate) -66;
protanomal-6;
deuteranomal - 6.

norm (trichromate) -36;
protanomal-36;
deuteranomal - 36;

norm (trichromate) -14;
protanomal-14;
deuteranomal - 14;
with severe acquired pathology, the figure is not visible.

norm (trichromate) -9;
protanomal-9;
deuteranomal - 9;
with severe acquired pathology, the figure is not visible.

norm (trichromate) -4;
protanomal-4;
deuteranomal - 4;
with severe acquired pathology, the figure is not visible.

norm (trichromate) - 13;
protanomal - nothing;
deuteranomal - nothing.

Interpretation of test results

To detect deviations, a check with 27 images is sufficient. In the case of simulation or under other circumstances, at the discretion of the specialist, checklists (20 more) are used to pinpoint the problem.

First of all, a weakened perception of green or red colors by the tested patient is revealed. This deviation is considered an anomaly and is called dichromasia.

Dichromasia involves violations of color perception and the difference between not all colors.

Allocate:

Lack of color perception of red, called protanopia. Protanopia is characterized by a darker vision of red and its merging with dark green and dark brown. In this case, the green color becomes close to light gray, light yellow and light brown. The reason for the deviation is the absence of photosensitive pigment in the retina.
Lack of color perception of green, called deuteranopia. Deuteranopia refers to the inability to distinguish green from light orange and light pink. And red can be perceived as light green and light brown.

Protanopia and deuteranopia are congenital disorders of color receptors. Tritanopia is much less common, most often has an acquired character.

Then the anomaly shape is classified into three types:

The complete absence of perception of red and green colors refers to type A.
Significant color perception problems are type B.
Slight deviations in color vision suggest type C.

In addition to the above deviations, more rare species are recognized using tables:

monochromatic (all three colors are not perceived);
abnormal trichromasia (inability to determine the difference in shades of three colors, when determining the three primary colors and with a reduced presence of pigments).

Thus, if you have all three pigments present, you are able to correctly distinguish the primary colors (red, green and blue). If any of them is missing, then you suffer from various types of color blindness.

There may be cases when the reason for the weakening of color perception is a decrease in the activity of one of the pigments, and not its absence. Then you are an anomalous trichromat.

How to pass a color perception test well for a driver

In the absence of deviations, passing the test does not require additional preparation and special efforts on the part of the test person.

You need to follow the simplest basic points:

General health should be within normal limits.
Make sure that the lighting in the testing area is sufficient and natural.
Position your back to the main light source.
Make sure the image is at eye level.
Look at the picture quickly, taking a few moments for each.

Identification of deviations is not a reason for a disorder, let alone resentment against a doctor. Most likely, this is a call to action. In this case, an ophthalmologist does not read out the verdict to you, but perhaps tries to come to the rescue and protect you from much bigger troubles (for example, accidents).

Violation of color perception should not provoke the search for workarounds for its passage. With a pathology in the perception of colors, it is not possible to pass the test successfully. It is useless to memorize the tables, since the images are provided selectively and in any order.

Understanding the seriousness of this issue can affect not only your safety, but also save the lives of those around you. The likelihood of difficulty in determining a traffic light change should make you think that you should not take risks and drive a vehicle or work as a driver.

What to do if the driver has violations

There are two main types of color blindness: congenital and acquired. Congenital pathology of the retina, unfortunately, cannot be corrected at the moment. The way to see the world in the same way as other people for colorblind people is to wear specially designed contact lenses.

Scientists are also working on the technology of introducing the appropriate genes into the cells of the retina.

Age-related color blindness is incurable. But sometimes, when the lens is replaced, color perception returns to normal.

It seems possible to cure an acquired anomaly of color perception by studying the causes of its occurrence.

If the color vision disorder was caused by chemical damage, there is a chance of a full recovery if it is canceled.

Trauma is often the cause of loss of color vision. In this case, the result of restoring the vision of colors depends on its severity. Sometimes there is a complete cure, and vision becomes normal.

In general, the deviation of color perception from the norm in itself does not pose a danger to human health. However, if this anomaly is detected in persons whose professional activities are related to color recognition, then it is necessary to take this issue seriously and find a more suitable type of activity.

Restrictions in activities for people with impaired color perception

Certain occupations require a mandatory eye test for color blindness.

These include:

drivers;
machinists;
sailors;
pilots;
highly specialized doctors.

Identification of visual deviations associated with color blindness does not allow people to get a job in these specialties or continue their professional activities.

Color blindness makes it difficult to perceive and fix road signals correctly. In some countries, people diagnosed with color blindness are denied a driver's license.

The main requirement for drivers and underlying this limitation is the ability to recognize traffic signals and other color images, which forms the basis of traffic rules and affects its safety.

4.8 (96.67%) 12 votes

Color blindness, color blindness is a hereditary, less commonly acquired disease related to the peculiarities of human vision and is expressed in the inability to distinguish one or several colors at once. The disease is named after John Dalton. This self-taught chemist was the first to describe color blindness in 1794, based on his own sensations.

John Dalton could not distinguish red, but he did not know about his color blindness until the age of twenty-six. He had a sister and three brothers, two of whom also suffered from color blindness precisely to red. John Dalton in his book describes in detail the family defect of vision, thanks to which in the future the concept of "color blindness" appears, which has become synonymous with visual anomalies both in red and in other colors.

The reasons

In the central part of the retina are color-sensitive cone receptors - special nerve cells. Each of the three types of these cones has its own type of protein-derived color-sensitive pigment. The first type of pigment is sensitive to red colors (maximum 570 nm), the second type of pigment is sensitive to green colors (maximum 544 nm), the third type of pigment is sensitive to blue colors (maximum 443 nm).

People who have normal color vision have all three pigments (red, green, blue) in their shells in sufficient quantities. They are called trichromats.

As noted above, color blindness can be congenital or acquired. Let's consider both types.

The hereditary transmission of color blindness is associated with the X chromosome and is more often transmitted from the carrier mother to the son, which is why men appear twenty times more often than women. From 2 to 8 percent of men and less than half of a percent of women suffer from varying degrees of color blindness.

At the same time, some types of color blindness are not considered a “hereditary disease”, but a certain feature of vision. So, according to the results of research by British scientists, those people who cannot distinguish between red and green colors distinguish many other shades (for example, shades of khaki, which seem the same to people with normal vision).

Acquired color blindness develops only in the eye, where the optic nerve and retina are affected. With this type of color blindness, there is a progressive deterioration and some difficulty in distinguishing between yellow and blue.

Causes of acquired color vision disorders:

age-related changes - cataract (clouding of the lens). Both color perception and distance vision are reduced;
taking various medications, which can lead to both temporary and permanent violation of color perception;
eye injury resulting in damage to the retina or optic nerve.

Symptoms

If there is no visual pigment in the retina, a person can distinguish only 2 primary colors. Such people belong to the category of dichromats. In the absence of the pigment that is responsible for the recognition of red colors, they speak of protanopic dichromacy, in the absence of green pigment - of deuteranopic dichromacy, in the absence of blue pigment - of tritanopic dichromacy. If the activity of any pigment is only reduced, we are talking about anomalous trichromacy. Such conditions are called protanomaly, tritanomaly and deuteranomaly (depending on the color, the perception of which is weakened).

Most often in medical practice there are violations of red-green vision - in 8% of men and 0.5% of women. At the same time, in 75% of clinical cases, doctors diagnose abnormal trichromacy.

Diagnostics

Color blindness limits the ability of some people to perform their work duties. The vision of doctors, drivers, pilots and sailors is carefully examined before being hired, as its violation can lead to danger for many people.

The oculist determines the nature of color perception using special polychromatic tables according to Rabkin. The set consists of twenty-seven color sheets - tables with images of many colored dots and circles that have the same brightness and different colors. To a color-blind person who does not distinguish some colors in the picture, the table seems homogeneous. A normal trichromat (a person with color perception within the normal range) distinguishes between numbers and geometric shapes, which are made up of circles of the same color.

Also, diagnostics allows the oculist to identify the blind in red and green. In the first case, the red color seems darker to the patient, it merges with dark green and dark brown. And the green color merges with light gray, light yellow and light brown colors. In the second case, the green color merges with light orange and light pink colors, and red with light green and light brown colors.

Treatment

Congenital color blindness is currently not treated. Treatment of acquired color blindness is also not possible in all cases.

With acquired color blindness, color perception is corrected by surgical intervention. If color blindness was provoked by another disease, it is first of all necessary to treat it. So, for example, if color blindness appeared due to a cataract, it must be removed, as a result of which vision may improve. If the development of color blindness occurred due to the use of medications, their cancellation is required. This measure may affect the restoration of color perception.

Also, attempts to correct color perception are made through the use of special lenses. The surface of such lenses is covered with a special layer, which in the process of color perception makes it possible to change the wavelength. Although this method may not bring special results.

Since congenital color blindness is not a progressive disease, patients are taught to self-correct their own color perception. For example, a person simply remembers that the red color of the traffic light is located on top, the green color is on the bottom.

In any case, the disease requires medical supervision by a professional, so if symptoms of color blindness appear, consult an ophthalmologist.

Folk remedies

Medicine does not know folk remedies with which color blindness could be cured.

Complications

Color blindness first came to public attention in 1875, when there was a well-known massive train wreck that resulted in heavy casualties. It turned out that the driver of this train was color-blind and did not distinguish between red, and the development of transport just at that time led to the widespread introduction of color signaling. This catastrophe influenced the fact that when applying for a job in the field of transport service, it became mandatory to evaluate color perception. A color-blind person must understand that his disease affects not only the quality of life, but also affects safety (both personal and other people).

Prevention

There is no way to prevent color blindness.

Men! Is it difficult for you to choose clothes so that they harmonize in color, choose ripe fruits among fruits, distinguish color images on a computer monitor, green and red traffic lights? Or does someone help you do it? This suggests that you have a color vision disorder or, as they also call it, a violation of color vision.

This problem is observed most often in every 12th Caucasian man and in every 200th woman. Most color blind people see other colors in addition to black and white, but they perceive some of them differently than a person with normal vision. As a rule, color vision impairment is inherited. The damaged gene disrupts the light sensitivity of retinal cells or the inner lining of the eye. But sometimes color vision can be impaired by a disease, then you need to contact an ophthalmologist.

In the human retina, there are usually three types of light-sensitive cells or cones that are sensitive to light waves of a certain wavelength and correspond to colors: blue, green and red. Each type of cone absorbs its own light wave and sends impulses to the brain and the person perceives the color correctly. But when color vision is impaired, the sensitivity of the cones decreases to one color or several, or the perception of the wavelength changes and affects color perception. Most people with this disorder are color blind: green, yellow, orange, red, and brown. Therefore, they do not notice green mold on black bread or yellow cheese and do not distinguish a blond from a red-haired person. When the sensitivity of cones, which are responsible for the perception of red, is sharply reduced, then a red rose seems black to them. Cases of color blindness to blue are very rare.

As already mentioned, photosensitivity disorder is inherited and, as a rule, is congenital. But many learn about it only when they grow up. The fact is that in children, the impaired perception of colors is often compensated by the ability to distinguish them unconsciously by brightness or contrast. Children associate their perceptions with common color names. In addition, they learn to distinguish objects by shape or texture, and not by color. And as adults, they learn that they suffer from a violation of color vision since childhood.

The school often uses colored aids, especially in elementary grades. And if the child does not know how to correctly distinguish colors, then teachers and parents mistakenly conclude that the child is not capable of learning. And in fact, he may have a violation of color perception. Sometimes the teacher even punishes the child for drawing green people, brown leaves on trees and pink clouds, but the child considers such colors to be completely normal, he just has color vision impaired. In some countries, for this reason, even young children are examined for color blindness.

Although color perception disorder is considered incurable, it does not worsen other visual functions over the years. But, nevertheless, this disease in some causes emotional distress.

Why is color vision impaired mostly in men? The X chromosome is responsible for inherited color perception. Women have two X chromosomes, while men have one X chromosome and the other Y . When a gene is damaged on one X chromosome in a woman, it compensates for a healthy gene on the other X chromosome and she retains normal vision. And men do not have a spare X chromosome, so the defect is not compensated.

How is a color vision test performed?

An eye test for color perception is carried out according to special tables with the image of many multi-colored circles. The 38 Ishihara tables are often used for this purpose. If a person has normal vision, then looking at the tests on the left in daylight, he will see the numbers 42 and 74. If a person has a violation of the perception of red and green (this most often happens), then he does not distinguish the number above, but sees the number 21 below. The tests given here are only an example, as the examination should be carried out by a qualified doctor. If a violation is detected, the doctor will prescribe an additional examination to determine the cause - it is hereditary or acquired.

Useful articles: