How color-blind people see the world, the colors that they do not distinguish. Famous people suffering from color blindness. Known to all colorblind

Many people have an erroneous idea of ​​color blindness, believing that the owners of this disease do not see colors at all or confuse them with others. It's just that in their color scheme one or another color has, depending on the type of color blindness, and the complete absence of colors is observed only in 0.01% of humanity.

Most normal people it is difficult to imagine how people with color blindness see, but scientists have already been able to study this pathology quite well and clearly show how perception changes in patients with color blindness. To date, there are several methods of getting rid of color blindness, but the easiest way is auxiliary contact lenses.

Despite the absence of complications, color blindness is still considered a physiological abnormality that must be treated, because the disease can interfere with professional activity: color-blind people are given rights, but they are forbidden to work, for example, as a driver for hire.

What is daltonism?

Color blindness is the inability to correctly identify certain colors. This phenomenon may be hereditary and be congenital, or be caused by a disease. optic nerve or retinas.

The first records of color blindness

For the first time, a visual defect in which a person does not distinguish between green and red colors was identified by the chemist John Dalton. This pathology was named after him. At the end of the 18th century, this discovery did not become a sensation, but was perceived as an inconvenience "to pick red strawberries in green grass."

Over time, it became clear that congenital color blindness is characteristic mainly of men. it official disease from the field of ophthalmology, which is characterized by the inability of vision to distinguish certain colors.

More often there is hereditary color blindness, but doctors do not exclude the fact of an acquired disease. Such visual defects are difficult to successfully correct, so patients do not perceive colors for the rest of their lives.

The disease manifests itself in childhood, so caring parents should consult a doctor in a timely manner for advice. Color blindness is a deviation from the norm, while vision, its main characteristics do not change.

The absence of differences in green and red tones in patients allows them to find shades of khaki that are not visible to an ordinary individual. The disorder does not negative influence on the quality of life of the patient, his professional activity.

How do people see in different categories of the disease?

The disease is divided into the following categories.

1. Anomalous trichromacy. This is a pathology of color perception in which a person does not fully distinguish between the three primary colors. This happens due to the absence of some cones or their incomplete functioning. Depending on which cones in the eye do not work, they share protanopia (incomplete perception of red), deuteranopia (problems with perception shades of green), tritanopia (a person cannot see blue).

   So, with abnormal trichromasia, the patient is in the color world, but the spectral range of the latter is somewhat different from the norm.

2. Dichromacy. A person with such a pathology sees the world in shades of two primary colors. While a healthy individual sees all shades of green, yellow, red, blue, a colorblind person with dichromacy sees only shades of red or green, not counting all the transitions of black and white.
3. Monochromatic. It is a complete inability to see colors. Occurs due to a strong defect in the cones or their absence. Complete color blindness is rare, since from the standpoint of evolution it does not contribute to the survival of the individual. AT wild nature an individual with monochromaty loses to those who see the world in all its variety of colors.

The most severe visual defects are dichromacy and monochromacy. People with these forms of the disease have limitations in the professional field. They have to solve many problems in everyday life: from color recognition in a traffic light to orientation in space using various identification marks.

What colors are invisible to the eye?

This disease is not so rare. Since color blindness is predominantly hereditary disease, most often it manifests itself in people living in closed communities.

Here, recessive (hidden) traits become homozygous, that is, pure form. Dominant (suppressive) signs of normal color vision such people are absent, therefore, a pathological perception of color appears.

Where the mobility of people is increased, their genomes are heterozygous (a variety of dominant and recessive traits), which reduces the likelihood of hereditary pathologies, including color blindness.

Color blindness is diagnosed by certain pictures with numbers, which are made in the form of colored circles. The surrounding world does not change form, but changes its shade. The patient himself does not notice such abnormal phenomena; his closest relatives and parents can sound the alarm.

The indistinguishability of primary colors can be called not only color blindness, but also color blindness. The essence of the matter does not change - the inability to distinguish color scheme is present. Colorblind people do not differ from people with normal color perception, but they have their own characteristics.

Women are more likely to experience such a disease, the first manifestations of the disease prevail in childhood. When seeing the same pictures, a sick and a healthy child give different answers.

The disease is accompanied by a lack of perception of red, blue or green hue. All sorts of modifications follow from this, as the color-blind people see the world.

What colors do they see?

Such an anomalous process occurs infrequently, for example, complete color blindness with life in a black and white world prevails in only 0.1 percent of all clinical pictures. In other cases, a color-blind person perceives colors in his own way, he also sees color pictures.

AT modern ophthalmology meet the following violations, which characterize one form or another of color blindness: with protanomaly, a patient of any age confuses red with brown, gray, black, green, brown.

With deuteranomaly, there are certain difficulties in perceiving a green tint, it is confused with red and orange; with tritanopia, purple falls out of the usual worldview, patients do not perceive the blue color.

What colors are confused?

In case of violation of color spectra, there is an inability to distinguish and poorly see the main tones, to correctly identify objects different colors. The type of pathology depends on the characteristics of color perception, as they see the world colorblind.

Some patients are able to distinguish part of the color shades, others see the world in black and white. How the type of disease will be called can be determined by special tests by the attending physician. Color blind people confuse red, blue, purple and green.

Development mechanism

The term first appeared at the end of the 18th century thanks to the work of the English doctor John Dalton. It was he who for the first time was able to describe the features of color perception in such patients, based on his feelings. Color blindness occurs due to the peculiarities of the retina, which is responsible for light perception.

It is a nerve formation at the back of the eye. His the main task- convert light to nerve impulses, which then follow to the brain. Color blindness causes a failure to distinguish one or more colors.

There are 3 types of cone cells (cones) responsible for light perception. Correct perception, adequate color differentiation is possible only with correct work these cone cells. Color blindness develops if one or more types of cells are missing or cannot work properly.

In this case, the corresponding color is not perceived at all or undergoes changes. Cone cells are predominantly located in the center of the retina. This ensures clear, sharp color vision. The name of the disease color blindness and the problem of light perception are synonyms.

Patients often distinguish colors a little, but some still do not distinguish them at all. Signs of color blindness, the reasons for their appearance are different. More often they are associated with genetic disorders therefore present from birth.

Other causes of vision include age-related changes, comorbidities. Similar reasons color blindness often occur in men. It is important to note: hereditary lesions are more common than acquired.

Almost all color disorders are associated with genes that regulate the pigments in cone cones that perceive color. These genes are located on the X chromosomes. Women have 2, and men only 1. This explains the prevalence similar ailments among the male population.

Women often do not suffer from color blindness themselves, but pass it on to their sons along with the X chromosome. Acquired problems can have many reasons for their development:

• aging increases the chance of a color problem;
• side effects of some drugs cause temporary or permanent color problems;
• a number of ailments (cataracts) cause temporary or permanent problems (the treatment of color blindness is based on the fight against the root cause of the disease);
• eye wounds in the area of ​​the optic nerve.

Causes of color blindness

Most often this congenital feature, it is due to the fact that color-sensitive receptors - cones - are damaged on the retina. They contain their own type of pigment - red, green, blue. If the pigment is sufficient, then the color perception of a person is normal.

If there is a lack of it, then one or another type of color blindness occurs - depending on which pigment is missing. Color blindness can be congenital or acquired. Congenital is transmitted through the maternal line through the X chromosome.

Why women get sick less often

In women, a damaged one X chromosome can be compensated for by an intact second one, while in men there is no such compensatory possibility. Therefore, they have this feature more often than women. In women, color blindness can occur if the father has it, and the mother is a carrier of the mutated gene.

According to statistics, one or another type of color blindness exists in every tenth man and in 3-4 women out of 1000. Acquired occurs due to age-related changes, taking certain medications, or due to injury to the retina or ophthalmic nerve, retinal burn by ultraviolet light.

It occurs in women and men about the same. With this form, people most often have difficulty in perceiving yellow and of blue color. The main cause of eye disease is the hereditary transmission of the gene from mother to son.

Therefore, eight percent of white men suffer from color pathology. In women, it is extremely rare, about half of a percent are color blind. Residents of Asian and African countries are not threatened with hereditary color blindness.

Acquired forms of the disease occur due to:

1. neurological, infectious pathologies;
2. traumatic lesions of the optic nerves, retina;
3. complications after meningitis, encephalitis, influenza;
4. age-related changes - cataracts, glaucoma;
5. taking medicines.

It is possible to cure the disorder if it appeared during life, being an acquired anomaly. Scientists in some countries are trying to correct the perception of colors with the help of multilayer lenses that allow you to look at the world in a new color.

Geneticists conduct experiments, taking root inside the chromosome, correcting the hereditary anomaly. Research is being carried out successfully, and soon the experiment will reach the level of medical practice.

How do people with color blindness see the world?

Color blindness is not a disease, but a visual defect. These people have good eyesight, but they see a little differently than the rest. People with a different color perception often perceive the world around us differently than we do, but often do not notice their difference.

It is rarely noticed by others. After all, color-blind people from childhood learn to call colors by common names. They remember that the sky is blue, grass is green, strawberries are red. They also have the ability to distinguish colors by the degree of lightness.

Many colorblind people can see many more shades that a person with "normal" vision cannot distinguish. Visual acuity in colorblind people is often much better than in ordinary people. There are colorblind people who can see perfectly in the dark.

Colorblind children

It is very important to diagnose color blindness in children - and as early as possible. Due to this feature of vision, the child does not receive all necessary information about the world around them, and this negatively affects their development.

The difficulty also lies in the fact that children under 3-4 years old cannot consciously name colors, and it is necessary to teach him to correctly identify them before this age. Therefore, the kids need to be observed - mainly for how they draw.

And if a child constantly makes mistakes in drawing familiar objects of nature - for example, he draws grass in red, and the sun in blue, this is a reason to suspect he has color blindness. True, confirmation of this may take several years.

Color perception

The central part of the retina has nerve cells also called "cones". They contain three types of color-sensitive pigments of protein origin. Each of the pigments is sensitive to different colors: red, green and blue.

To be precise, they are sensitive to the wavelength corresponding to these colors in our understanding. The vision of all the colors of the world is made up of these three colors in our brain. People with normal color perception have all three pigments in their "cones" and are called "trichromats".

The most common defect in red pigment is in the "cones", but people with a defect in blue pigment are the least common, as well as people who have no color vision at all.

If a person differs in only two colors, then he is called a “dichromate”, one pigment in his retina is missing.

genetic color blindness

Blindness to red-green colors is most often inherited. The reason for this or that type of color blindness is molecular defects in the genes responsible for the synthesis of color-sensitive pigments.

Modern science has identified all the genes that encode the pigments responsible for each color. At this stage in the development of medicine, it is possible to “fix” a defective gene. Although so far such experiments are carried out only on animals.

Types of hereditary problems

The disease is divided into 4 main types. The most common of these is anomalous trichromasia. It occurs in individuals with three types of cone cones. They are, but they do not work correctly. Such people can usually see primary colors, but not in the same way as others. That is, the colors are perceived, but not correctly.

The second type of problem is dichromacy. Occurs when 1 of the 3 types of cones is absent altogether. Vision is kept at the level of "visualization of 2 of 3 primary colors". Usually such patients distinguish blue and yellow well, but find it difficult to distinguish between red and green.

Rarely they do not perceive blue and yellow. In this case, patients have more serious violations color vision. The third type of disturbance is blue cone monochromacy. It happens when two types of cones (red and green) are missing.

Patients confuse or do not distinguish them at all. The absence of defining elements affects only the male part of the population. Such patients have poor eyesight at a distance, they often have involuntary eye movements (most often horizontal nystagmus).

Patients with monochromasia see colors, but not all. They distinguish only blue shades from the entire spectrum. The fourth, main type of hereditary pathology is achromatopsia. All three types of cones are absent. Colorblind people see poorly. Other visual impairments often develop, including:

• poor vision at a distance;
• visual impairment when reading;
• sensitivity to light and illumination (photophobia).

Such a problem is considered the most difficult and rare. Patients, even at home, often cannot navigate.

Types of color blindness

Determining the causes of color blindness is problematic, but it is important to understand how the abnormal process proceeds. The problem is in the modification of the spectral sensitivity of pigments, which distorts the brightness and contrast of the picture.

If there is no blue pigment on the retina, and the condition is hereditary, successful treatment is difficult. When red or other shades are distinguished, but they are confused, and the pathology is acquired, it can be eliminated by wearing special glasses.

The inability to see the world correctly can be fought, it all depends on the types of pigments, the form of trichromasia. Colorblind people poorly perceive shades of certain colors, in accordance with this, a classification was created:

• protanomaly - a violation of the perception of red;
• deuteranomaly - the difficulty of distinguishing the green color (mixing it with orange, red);
• tritanopia - problematic perception of purple and blue (all such shades appear red or green);
• rarely, but there is complete blindness to green or red.

How to define color blindness? Serious problems color vision is easy to detect. The patient does not distinguish colors at all. Such people see only shades of gray, black and white. Types of color blindness differ in their prevalence.

Inherited color vision disorders are always bilateral; the degree of damage is the same in both eyes. Color blindness is present at birth and does not change over time. Acquired problems can affect only one eye.

With bilateral lesions, the degree of impairment may differ in the two eyes. Such violations change over time and age of the patient. As mentioned above, color blindness can be acquired and hereditary.

Acquired color blindness can occur only in the eye, where the nerve or retina is damaged. It tends to progressively deteriorate over time and has difficulty distinguishing between blue and yellow.

However, hereditary color blindness is much more common. In this case, both eyes are affected and it does not worsen over time. This variant of color blindness is typical for 8% of men and 0.4% of women.

Hereditary color blindness is associated with the X chromosome. Women have a pair of X chromosomes, while men have only one X chromosome. In this regard, in women, a congenital anomaly is possible when defective genes are found on both chromosomes, which happens extremely rarely.

The whole irony lies in the fact that the “carrier” of color blindness is a woman who passes it on to her son. Depending on the cause of the appearance of color blindness, there are:

1. Congenital, or hereditary. It passes from mothers to sons. The fact is that the gene that leads to color blindness is localized on the X chromosome and is dominant. As you know, the genotype of a man is represented by a set of XY, and women - by XX. Thus, if a mother is a carrier of an abnormal gene, she will pass it on to her son in 100% of cases. A woman can get sick only if both her parents suffer from color blindness. This happens extremely rarely (more details can be found here);
2. Acquired. It develops as a result of diseases of the optic nerve and retina (cataract, macular degeneration, glaucoma, diabetic retinopathy). More often it is one-sided (that is, one eye does not distinguish colors). Acquired color blindness may be reversible (in the case of successful treatment underlying disease).

Complete (monochromasia, achromatopsia)

It is caused by the absence or abnormal development of all three types of cones. At the same time, everything is seen in black and white. As already mentioned, such an anomaly is extremely rare;

Women and men suffer from color blindness, and a number of pathogenic factors precede impaired color perception. If people are not able to perceive all shades, we are talking about complete trichromacy.

The disease is extremely rare, significantly limits the possibilities modern man, for example, he will not become an artist and is not destined to manage his personal vehicle(problems with traffic lights). All three membranes are involved in the pathological process, their abnormal development.

Partial

Patients are able to perceive individual colors and shades, and some of them still confuse, see incorrectly. If people partially suffer from color blindness in a particular clinical picture, doctors determine and distinguish the following types of trichromasia and their short description for better understanding:

• Dichromasia (dyschromatopsia), in which one type of cone is not involved in color perception. People who suffer from dichromacy are called dichromats. Depending on which type of receptor is damaged, dichromasia is divided into:
  1. Protanopia, in which there is no perception of the red spectrum;
  2. Deuteranopia, in which the perception of the green spectrum is impaired;
• Tritanopia, in which the perception of the blue part of the spectrum does not occur.

Diagnosis of the disease

To determine the ability of a person to distinguish colors, various tests are used. The most famous study is the pseudo-isochromatic test. During this procedure, the person is asked to look at a collection of colored dots in order to identify a pattern - it can be a number or a letter.

The type of violation is determined depending on what samples the patient sees during the test. If a person has an acquired color vision problem, a color distribution test is used.

People who have problems with color perception cannot lay out the plates correctly. The most well-known method for detecting color vision disorders is the pseudo-isochromatic plate test.

The type of disease that is associated with the defeat of light perception is determined by what samples a person sees or does not see using these test plates. With acquired color blindness, a person notices symptoms immediately.

To confirm the diagnosis, methods of distributing objects by color are used. The patient should arrange objects according to certain color or tint. In the presence of pathology, a person is not able to perform such a task correctly.

Ways to overcome color blindness

It would be logical to describe the problems of people with defects color perception on the example of John Dalton himself. This scientist, who lived at the turn of the 18th and 19th centuries, did not know about the features of his vision until almost 30 years old.

One day he decided to take up botany. In this science, it is extremely important to distinguish the color shades of all parts of the plant. Here it turned out that Dalton could not adequately navigate in the shades of the red spectrum.

Botany was difficult for Dalton, but nothing prevented the scientist from describing in detail the manifestation of a visual defect that was common to all his brothers and sisters. Since then, the name Dalton has become the name for a disease that is associated with some features of the human genome.

Treatment of color blindness

Color blindness, or a violation of color perception, is most common in men. For the first time this violation was described by John Dalton, after whom this feature of vision was named. He himself before middle age did not suspect that his own perception of the color red was different from that of most people. How color blind people see colors and about the varieties of color blindness, read in this article.

Color blindness was not considered something particularly dangerous until one day on railway there was no accident due to the driver not perceiving red and green colors. Since that time, people in professions where it is critically important have been carefully checked, and color blindness of any kind has become an insurmountable contraindication.

Causes of color blindness

Most often, this is a congenital feature, it is due to the fact that color-sensitive receptors - cones - are damaged on the retina. They contain their own type of pigment - red, green, blue. If the pigment is sufficient, then the color perception of a person is normal. If there is a lack of it, then one or another type of color blindness occurs - depending on which pigment is missing.

Color blindness can be congenital or acquired.

Congenital is transmitted through the maternal line through the X chromosome. In women, a damaged one X chromosome can be compensated for by an intact second one, while in men there is no such compensatory possibility. Therefore, they have this feature more often than women. In women, color blindness can occur if the father has it, and the mother is a carrier of the mutated gene. It can also be passed on to the child

According to statistics, one or another type of color blindness exists in every tenth man and in 3-4 women out of 1000.

Acquired occurs due to age-related changes, taking certain medications, or due to trauma to the retina or optic nerve, retinal burns with ultraviolet light. It occurs in women and men about the same. With this form, people most often have difficulty in perceiving yellow and blue colors.

Types of color blindness

People with normal color perception often have a question - how do color blind people see colors, how the world appears before them. It all depends on what kind of color blindness a person has. Sometimes his world is also full of colors, but only one spectrum of color is not perceived, or his vision is distorted beyond recognition.

Depending on which pigment is missing, there are various violations color perception, in which a person cannot distinguish one or another color.

Achromasia and Monochromasia

If there is no pigment of all colors in the cones at all, the eye sees only shades of black and white, and there is no color vision at all. This is the most rare form color blindness. A person distinguishes colors only by their brightness and saturation. An illustration of this perception can be black and white photography or old black and white films.

There is also monochromasia - the pigment is present in only one of the cones. This is a form of color blindness in which all colors are perceived as one color background, most often red. In this case, a person sees many more shades of this color than with normal vision - this is a compensatory function of the brain. Old photographs can also serve as an example, for the development of which some kind of paint was added to the reagents. Then a person does not perceive gray shades during the day either, they are seen in the same color scheme that is present in the cone.

dichromasia

With this pathology, a person distinguishes two colors in the daytime. Also, this pathology is divided into subspecies

Protanopia

When red is not distinguished, and all shades in a given color range. The pathology is called protanopia.

This situation is fraught with danger for a person on the road - he simply may not understand the traffic lights. This pathology is most common, and instead of red, the eye perceives a color approaching yellow. At the same time, yellow remains yellow. Sometimes the eye sees instead of red grey colour, as Dalton himself did - he was explained that his favorite dark gray jacket was actually burgundy.

Deuteranomaly

When you can't see green. This pathology is called deuteranomaly.

This pathology is quite rare, most often it is discovered by chance. The world for a person with deuteranopia looks unusual for normal color perception - green tones are mixed with red and orange, and red with green and brown. Therefore, a red sunset in his perception looks blue, green leaves also appear blue or dark brown.

Tritanopia

When you can't see blue. This condition is called tritanopia.

This is the most rare pathology in which a person cannot distinguish colors in blue-yellow and purple-red. At the same time, blue and yellow colors look the same, and purple is identical to red. However, most people distinguish purples from greens. This pathology is most often congenital. With this type of color blindness in humans, most often it is also weakened twilight vision. But otherwise the eye is healthy, visual acuity is not impaired.

Anomalous trichromasia

When a person has enough of all the pigments in the cones, then the state of color perception is called trichromasia, while he does not have color blindness, and in this respect his eyesight is healthy.

There is also a violation when all the pigments are evenly lacking - then the colors for color blind people remain in muted tones, not so bright and saturated, and some shades become inaccessible to him. It's also enough rare view color blindness. Recent studies have shown that this is how dogs see the world around them.

People with red and green perception disorders are able to perceive many shades of khaki, which in normal color perception appear to be the same gray.

This is a pathology in which a person sees everything in blue tones.

This is a very rare pathology, always acquired. It occurs when the eye is injured, most often after the removal of the lens, so a lot of short light rays enter the retina. This greatly complicates the perception of red and green shades. It can also occur when inflammatory phenomena on the retina. It happens that such a color perception in a person is reduced, and visual acuity is low.

This is a similar disease, also always acquired.

With this disease, the eye loses the ability to see the colors of the red and blue spectrum, only green is perceived. It occurs with various organic poisoning of the body, with dystrophic and inflammatory phenomena in the retina. At the same time, the human condition may be aggravated, the perception of green shades may also narrow, visual acuity may decrease, and intolerance to bright lighting may occur.

Mainly men are subject to it.

There is also such a temporary and rapidly passing condition as erythropsia - with it, a person sees everything in red colors.

Wherein White color perceived as yellowish. This condition occurs after eye operations, with "snow" blindness in skiers and climbers - it is also known as "snow blindness", when the cornea is exposed to ultraviolet radiation (for example, when quartzing a room). It quickly passes by itself, no treatment is required. If such vision has not passed in a couple of days, you need to contact an ophthalmologist and wear good sunglasses for several days.

Diagnostics

To identify color blindness in a person is often obtained almost by accident during examinations by an ophthalmologist. For this, special tables and tests are used that help to identify the degree of color blindness and its type - pseudo-isochromatic tables of Stilling, Ishihara, Schaaf, Fletcher-Gambling, Rabkin. The most common self-test methods are based on the properties of color and are a set of circles that differ slightly in color and saturation. In the table, with the help of these circles, numbers, geometric shapes, letters, etc. are encrypted. Only a person with normal color perception can distinguish them. People with pathology in these tables will see other encrypted signs that are inaccessible to normal vision.

However, the quality and objectivity of the test can be affected by many factors - age, eye fatigue, lighting in the office, general state subject. And although these tables are quite reliable, if necessary, a deeper check is needed, for example, using a special device - an anomaloscope. With this test, a person is asked to select colors that are in different fields of view.

Colorblind children

It is very important to diagnose color blindness in children - and as early as possible. Due to this feature of vision, the child does not receive all the necessary information about the world around him, and this negatively affects their development. The difficulty also lies in the fact that children under 3-4 years old cannot consciously name colors, and it is necessary to teach him to correctly identify them before this age. Therefore, you need to watch the kids - mainly how they draw. And if a child constantly makes mistakes in drawing familiar objects of nature - for example, he draws grass in red, and the sun in blue, this is a reason to suspect he has color blindness. True, confirmation of this may take several years.

Treatment

To date, it is impossible to cure congenital color blindness. This is a lifelong feature, but research is being carried out and methods are being developed (so far only in a computer version) for implanting the necessary pigment into cones. Special glasses are also being developed that can help a color blind person see the world in the “correct” colors.

With acquired color blindness, this disease is most often curable. This is especially true for taking medications - it is enough just to cancel them and after some time color perception is restored.

Color blindness is the complete or partial inability to distinguish colors in normal conditions lighting. The disease is observed in a significant number of people around the world, although in different groups their percentage can vary significantly. For example, in Australia, 8% of men and only 0.4% of women suffer from color blindness. In isolated communities where the genetic pool is limited, often a large number of people with this deviation, including its rare variations. Such communities are, for example, countryside Finland, Hungary, some Scottish islands. How color-blind people see it depends on the individual and the form of his disease. In the United States, about 7% of the male population (almost 10.5 million people), as well as 0.4% of women, cannot distinguish red from green or see these colors differently from other people. Very rarely, the disease extends to shades from the blue spectrum.

Causes of color blindness

As color blind people see, it is due to subspecies of the disease, each of which is caused by certain deviations. The most common cause is a defect in the development of one or more cone-shaped visual cells that perceive color and transmit information to the optic nerve. This type of color blindness is usually dictated by gender. The genes that produce photochromic substances are found on the X chromosome. If some of them are damaged or missing, the disease in men is more likely to manifest itself, since they have only one cell of this type. Women have two X chromosomes, so usually missing substances can be replenished. Color blindness can also result from physical or chemical damage to the eye, optic nerve, or parts of the brain. For example, people with achromatopsia completely lack the ability to perceive colors, although the violations are not of the same nature as in the first case.

In 1798, the English chemist John Dalton published the first scientific work on this topic, thanks to which the general public became aware of how color blind people see. His research " Unusual facts about the perception of colors ”was the result of awareness of his own disease: the scientist, like some other members of his family, did not see shades from the red spectrum. Color blindness is usually considered slight deviation, however, in some cases it provides certain advantages. So, some researchers have come to the conclusion that those suffering from color blindness are able to better distinguish camouflage. Such discoveries may explain the evolutionary reason for the large prevalence of color blindness in the spectrum of red and green. There is also a study stating that people with certain types of the disease are able to see colors that others cannot see.

Normal color vision

To understand how color blind people see colors, it is necessary to consider the mechanism of perception in general view. Normal retina human eye contains two types of light-sensitive receptors, the so-called rods and cones. The former are responsible for vision at dusk, while the latter are active in daylight. Three types of cones are usually present, each containing a specific pigment. Their sensitivity is not the same: one type is excited by a short wavelength of light, the second is medium, and the third is long, with peaks in the blue, green and yellow regions of the spectrum, respectively. Together they are expected to cover all visible colors. These receptors are often referred to as blue, green, and red cones, although this definition is not accurate: each type is responsible for the perception of a fairly wide range of colors.

How do color blind people see the world? Classification

In the clinical picture, full and partial color blindness are distinguished. Monochromasia, complete color blindness, is much less common than the inability to perceive individual shades. The world through the eyes of a color blind person with this disease looks like a black and white movie. The disorder is caused by a defect or absence of cones (two or all three), and color perception occurs in one plane. Concerning partial color blindness, from point of view clinical manifestations there are two main types of it, associated with the difficulty of distinguishing between red-green and blue-yellow.

• Complete color blindness.
• Partial color blindness.
• *Red Green.
• ** Dichromasia (protanopia and deuteranopia).
• **Anomalous trichromasia (protanomaly and deuteranomaly).
• *Blue yellow.
• ** Dichromasia (tritanopia).
• ** Abnormal trichromasia (tritanomaly).

Types of partial color blindness

In this classification, there are two types of hereditary color vision disorders: dichromasia and anomalous trichromasia. What colors do not distinguish color blind depends on the subtypes of the disease.

dichromasia

Dichromasia is a disorder of moderate severity and consists in the malfunctioning of one of the three types of receptors. The disease occurs when a certain pigment is missing, and color perception occurs in two planes. There are three types of dichromacy based on which type of cone is not working properly:

• first: Greek "prot-" - red;
• the second: "deutra-" - green;
• third: "trit-" - blue.

Want to know how color blind people see? A photo can give a visual representation of the features of their picture of the world.

Forms of dichromasia

• Protanopia- This is a disorder in which an individual can perceive light with a wavelength of 400 to 650 nm instead of the usual 700 nm. It is caused by complete dysfunction of red photoreceptors. The patient does not see pure scarlet flowers, which appear black to him. Purple is the same as blue to an individual, and orange looks dark yellow. All shades of orange, yellow, and green, whose wavelength is too long to stimulate blue receptors, appear in a similar tone of yellow. Protanopia is a congenital, sex-related disease that occurs in about 1% of men.
• Deuteranopia implies the absence of photoreceptors of the second type, which makes it difficult to distinguish between red and green.
• Tritanopia- a very rare disorder, which is characterized by the complete absence of blue pigment. This color looks greenish, yellow and orange - pinkish, purple - dark red. The disease is associated with the 7th chromosome.

What color-blind people see: abnormal trichromasia

This is a common type congenital disorder color perception. Abnormal trichromasia occurs when the spectral sensitivity of one of the pigments is altered. As a result, the normal perception of color is distorted.

• protanomaly- an insignificant defect in which the spectral sensitivity of red receptors changes. It manifests itself in some difficulty in distinguishing between scarlet and green colors. congenital disease, due to gender, is present in 1% of men.
• Deutranomaly caused by a similar shift, but in the spectrum of perception of green. This is the most common type, to some extent affecting the discrimination of colors from the previous case. Sexually inherited disorder occurs in 5% of European men.
• Tritanomaly- a rare disease that affects the distinction between blue-green and yellow-red. Unlike other forms, it is not determined by gender and is associated with the 7th chromosome.

Diagnosis and treatment

The Ishihara test contains a series of images consisting of colored spots. The figure (usually Arabic numerals) is embedded in the drawing as dots of a slightly different hue that can be distinguished by people with normal vision, but not with a particular type of disorder. The full test includes a set of images with various combinations to determine if the disorder is present and specifically what colors color blind people do not see. For children who do not yet know numbers, drawings with geometric shapes (circle, square, etc.) were developed. Anomalous trichromacy can also be diagnosed with an anomaloscope. Currently does not exist effective methodology treatment of color blindness in humans. Colored lenses may be used, which improve the discrimination of some colors, but at the same time make it difficult to correctly perceive others. Scientists are testing the treatment of color blindness using methods genetic engineering who have already given positive results in a group of monkeys.

Color blindness is a deviation from the norm in color perception. Pathology causes a change in the sensitivity of special photoreceptors, which are located in the outer layer of the retina. Unlike ordinary people, color-blind people see the world in an incomplete color spectrum or even in black and white. The anomaly is more often manifested in the representatives of the stronger sex. Color blindness affects 8% of men versus 0.4% of women.

Color blindness from the point of view of medicine: types, symptoms, diagnosis

Doctors do not consider altered color perception a disease, it is rather a feature of vision. In most anomalous cases, the ability to distinguish color does not disappear completely, but is weakened. But in parallel, a person gets the opportunity to distinguish more shades in another part of the spectrum, which is not available to people with normal vision.

Name history

color blindness, or medical language, "color blindness" is named after the English naturalist, who most suffered from this pathology - John Dalton. Until the age of 26, a scientist who was actively engaged in research in several areas at once: chemistry, physics and meteorology did not realize that he perceives the world differently from those around him. One day, while studying botany, Dalton discovered that a wild flower, which seemed to him light blue in bright sunlight, suddenly turns purple by candlelight.

Sharing strange phenomenon with loved ones, the scientist found out that only his brother sees the same thing, the rest do not notice any color changes depending on the lighting. This led to the conclusion that both young Daltons have some kind of visual defect, and it is genetically determined. The scientist described his discovery in 1794, although he could not correctly indicate physical causes anomalies. Later it turned out that Dalton did not perceive the long-wavelength part of the spectrum: red shades seemed to him dull gray.

Causes of color blindness

The retina of the human eye is equipped with two types of photoreceptors: rods and cones. These are special cells that convert light signals into nerve impulses. They give the brain the ability to distinguish the shape, brightness and color of objects.

The sticks are responsible for black and white vision and activated in dark time days, so at night the world around seems monochrome.

Cones, thanks to the protein pigment iodopsin, provide a colorful perception of the world during the day. They are divided into three types: L, M and S. Each contains a certain type of iodopsin and absorbs electromagnetic radiation only with waves of a certain length, converting them into different colors.

The process can be seen in more detail in the table:

When present in cones three types pigments, a person perceives the entire visible palette of colors and is a trichromat. This is the standard view.

In colorblind people, one of the pigments: green, blue or red is partially or completely absent. The ability to distinguish colors because of this is reduced.

It is interesting: since the absorption peak of the green and red parts of the spectrum has approximately the same value, these two colors are most often not perceived by color blind people. Blue and violet hues help to "read" sticks that are sensitive to short waves, no longer than 500 nm.

Two sources of pathology

Color blindness can be caused by several reasons. It happens:

1. Congenital. This variety is transmitted genetically from a mother with a damaged X chromosome. If a boy is born, he will certainly suffer from color blindness, since he receives the X chromosome only from the mother, and from the father the Y chromosome, which cannot in any way affect the developmental deviation.

A girl is more likely to avoid color blindness if it is transmitted only through the maternal line. She inherits X chromosomes from both parents, and healthy DNA represses damaged DNA. But a girl can become a carrier of a recessive gene, which will manifest itself in the future, when her children are born.

It is hereditary color blindness that is considered a feature of vision. Sometimes people who are sensitive to one part of the spectrum at the expense of the other part of the spectrum are used to perform special tasks.

This is interesting: British scientists have found that when color-blind people see red as green, brown or gray, they can simultaneously distinguish many shades of khaki that are inaccessible to the average person.

This feature was used by the military. Soldiers with problematic color perception easily distinguished the enemy's camouflage among the grass and foliage.

1. Acquired. AT this case color blindness accompanies another, more serious ophthalmic disease and is included in the general clinical picture. It could be:

1. • cataract;
   • retinal diseases;
   • optic nerve damage.

Also, color perception problems arise with age, when vision weakens, with brain tumors or injuries. Taking certain medications affects vision, but after refusing them, the symptoms in most cases disappear. Acquired color blindness does not depend on gender, it occurs in both women and men.

If the pigment is absent in three cones at once, vision will be monochrome. Such a deviation occurs in about 1 person in 10,000. Since the anomaly is genetic in nature, in regions where the population lives in isolation and marriages between close relatives are allowed, the frequency of its manifestations increases.

Allocate:

• monochromacy, when a person sees different tones of the same color;
• achromatopsia - the complete absence of cones in the retina and a black and white perception of the world.

Usually, in color blind people, a partial anomaly is fixed - dichromasia. One of the cones ceases to perform its functions and waves of a certain length are not perceived by visual receptors.

Types of dichromacy:

1. Protanopia does not allow you to see in the red spectrum. A similar visual defect occurs in 0.66% of people. The world for them is presented mainly in yellow-blue colors, and shades of red seem to be gray.

1. Deuteranopia was recorded in 0.56% of the population. It is the inability to see in the green spectrum. Foliage and grass hues appear yellow or orange. Red is also almost indistinguishable.

1. Tritonapia is the rarest pathology, only 0.016% of cases. A person does not distinguish between blue and its shades. This type of dichromacy occurs equally in men and women and is provoked by a defect in the 7th chromosome pair.

Instead of shades of blue, greenish ones are perceived, and pink color, which color-blind tritanopes see, is actually yellow or orange.

The most mild form color blindness is called anomalous trichromacy. All three types of cones are involved in color transfer, but their activity is reduced. As a result, the perception of shades of blue, green or red is weakened. Accordingly, tritanomaly, deuteranomaly and protanomaly are distinguished.

Diagnosis of color blindness

An anomaly can be detected only in children who have reached the age of 3 years. For more early stages the child is not yet able to accurately determine and name the shades. What appears to be a visual defect may actually be a fantasy or an insufficient vocabulary.

adults pass various tests, among which the most productive tables are:

• Rabkin
• Ishihara
• Stilling
• Yustova

This can be done independently, at home. It is better to use Rabkin's tables - they give the most accurate result.

Important: so that the tests do not give errors, you need to pass them in calm conditions, with good lighting and monitor brightness (if the drawings are on the computer).

One of the examples of Rabkin's table. A color-blind person who does not distinguish between green and red colors will not see the numbers 8 and 74 in these drawings.

Doctors use the Holmgren method. 133 balls of wool of different tones and shades must be sorted into three groups according to the main colors. There are also hardware techniques, for example, the Nagel amaloscope, based on the comparison of two shades of yellow obtained in different ways.

Treatment

Doesn't exist yet effective ways fight against hereditary color blindness. But geneticists are working in this direction. In 2009, the results of the experiments of American scientists led by Jay Neitz were published, who cured two monkeys of the saimiri genus.

Adult animals were injected with therapeutic genes responsible for color sensitivity. And after 2 years, they began to produce the necessary photopigments themselves, “learning” to see the green and red shades of the spectrum. Scientists hope that in the future their developments will eliminate anomalies in visual perception and in man.

In the case of acquired color blindness, efforts are directed to the treatment of the underlying disease.

Important: genetic color blindness affects both eyes. It does not affect visual acuity in any way and does not provoke eye diseases. A person's condition remains stable throughout life. Symptoms of an acquired anomaly may worsen over time. With ophthalmic lesions, color vision disorders are recorded only in the diseased eye.

Corrective glasses can help color-blind people navigate the variety of colors of the world around them. Their lenses consist of several layers, "tuning" the human eye to the perception of light waves in the visible spectrum. Some signals are blocked with a special filter, others are amplified and made more contrast.

Each type of color blindness has its own lens design. A person gets a unique opportunity to see “like everyone else”.

Cons of the device:

• Glasses "work" only in the daytime in bright natural light;
• the price of the gadget is high - from $ 350;
• limited number of manufacturers.

Problems faced by color blind people in everyday life

In a world where much communication is done with color, people with vision problems have a hard time. Starting in 2017, color-blind people in Russia are prohibited from driving any type of transport, even if they use the car only for personal needs.

Previously, Russian legislation allowed people with a diagnosed color perception anomaly to obtain category A and B rights. European countries do not impose such restrictions, just like Canada or the United States.

In each case, the issue of obtaining rights by Russians is decided by a qualified ophthalmologist. But color-blind people will still not be able to work as a driver for hire. Some other professions are not available to them:

• pilot;
• sailor;
• train driver;
• chemist;
• designer;
• stylist;
• visagiste.

Violation of color vision is a serious obstacle to admission to medical school. Previously, the anomaly was a limitation for military service, but now in some branches of the military it is perceived more as a "plus".

In everyday life, it is more difficult for color-blind people to choose clothes, decorate the interior, use a computer.

This is interesting: many sites use purple-blue design, targeting visitors with color blindness. Most of them do not distinguish between the waves of the red or green spectrum, and almost everyone correctly perceives the shades of the sea and sky.

It is not difficult to be "in the shoes" of a person with impaired color perception. For this, there are interactive simulators or specially processed images.

Until the age of 26, he had no idea that he was not able to distinguish between the color red. He had two brothers, and they were also colorblind. Interestingly, the sisters did not have such a problem.

Dalton wrote a book in which he spoke about all the nuances of his illness. Thanks to this description, any violation of the perception of colors began to be considered color blindness.

The anomaly interested scientists who conducted a series of studies. It turned out that color blindness is a disease that is inherited from mother to son with the X chromosome. Men have XY chromosomes. If the defect is present in the X chromosome, then there is nothing to compensate for it, which is why the anomaly occurs twenty times more often in men.

Women have a pair of X chromosomes, so they can replenish the missing elements. Statistics show that approximately 8% of men are color blind, and among women they are only 0.4%. Cunning nature endowed women with the ability to transmit color blindness, but not to suffer from it themselves.

In addition to heredity, there is another reason for the development of color blindness - chemical or physical damage to the eye.

The fate of becoming colorblind can also await those who have received damage to parts of the brain or optic nerve. Severe flu, heart attack, stroke - all this can affect the perception of colors.

The world through the eyes of a colorblind

It is widely believed that color blind people see the world in black and white, but this is not true. This phenomenon is very rare, usually color blind people do not perceive any one of the primary colors. Most often it is red.

Cones are located in the center of the retina. They contain pigments that are sensitive to the wavelengths of red, blue and green. Thanks to their addition, people have the opportunity to see the world around them in different colors. Only ophthalmologists can correctly explain how color-blind people see the world.

Scientists distinguish two types of color blindness - dichromasia and anomalous trichromasia. The subtype of the disease depends on which colors are distorted in a person.

dichromasia- violation medium degree, is manifested due to the malfunction of one of the three receptors. This type of color blindness is divided into three forms:

1. Protanopia is a complete dysfunction of the perception of red. More often than not, a person sees everything red as black. Blue and purple appear to be the same, while orange appears deep yellow. The anomaly occurs in 1% of men.
2. Those who do not have photoreceptors of the second type do not distinguish between red and green. This form is called deuteranopia.
3. A rare form, but still found - tritanopia. Characterized total absence blue pigment. A person sees green instead of blue, pinkish instead of yellow and orange, and purple appears dark red.

The second type of color blindness is anomalous trichromasia. In practice, there are three forms of dichromacy:

1. The problem of green color perception is called deuteranomaly. The anomaly changes green to orange or red.
2. The inability to perceive red is protanomaly. A person sees brown, black, green or dark gray instead of red.
3. blue and purple colors do not see those who have tritanomaly. In this case, a person is not able to distinguish between blue-green and yellow-red colors.

By the way, blue immunity is very rare. That is why the design of many computer programs made in this color.

There are more serious disorders - monochromasia and achromasia.

monochromatic- this is a pathology in which they do not distinguish colors at all, but they perceive brightness well. Man is not able to see the world in those bright colors with which he can please people with normal vision.

Achromasia- even more complex pathology, in which a person not only does not distinguish colors, but also reduced visual acuity and photophobia. Because of this, he has to constantly squint. Simply put, this condition is called color blindness.

Colorblind people have good eyesight, they just see a little distorted. You can’t even call them sick, since their peculiarity does not bring discomfort, does not impair the clarity of vision. Sometimes color blindness goes unnoticed not only for others, but also for the owner of an unusual vision of the world.

It is difficult for an ordinary person to imagine how color blind people see colors - sometimes this is the subject of a dispute or joke. It is important to remember that such a special person will have to come to terms with their worldview for life.

Diagnosis of the disease

To identify problems with the perception of colors in humans, doctors use a specific test - Rabkin's polychromatic tables. Among the circles different color drawn figures, figures. A person with normal vision will immediately see what is drawn in the picture.

Color-blind people make great efforts to see the drawing, and some do not succeed at all. For young children, the same test has been developed, only various geometric shapes are located on it.

Now anyone can find these tests on the World Wide Web and independently determine whether he has color blindness, determine its type and form.

There are spectral devices that are also used in the diagnosis of color blindness. Most often they are used when applying for a job in such professions, whose employment is related to driving.

In practice, there have been cases when color blindness led to accidents, which is why employers so carefully check employees who are responsible for people's lives.

The first case that attracted general attention occurred in Sweden, in 1875. Then there was a train wreck, which claimed many human lives. It turned out that the driver simply did not distinguish red and did not know about this feature of his vision.

Not so long ago in Russia, color blindness was the reason for restrictions on the issuance of rights, and now the laws have become even more stringent. In Europe, there are no restrictions on issuing rights to color blind people.

After all diagnostic procedures the doctor informs the patient about what form of color blindness he has and what restrictions he may encounter in his life.

As for the treatment of this disease - it does not exist. There are methods of correction - lenses and glasses, but they are rarely used. Scientists are experimenting with monkeys to develop a treatment, and there are already some positive results.

Features of everyday life with color blindness

The person who sees environment through the eyes of a color-blind person, of course, may not feel comfortable because of their anomaly. For him, those professions that require the ability to clearly distinguish colors become inaccessible. He won't be able to get through medical commission and the job will be denied.

For example, a color-blind person cannot be a designer, since it is also important to correctly recognize colors there.

As for a driver's license, a color-blind person can get them after a certain training.

The restrictions that will be inevitable for him are the rights of categories only A and B, as well as a mark that will not allow him to work for hire. A car or motorcycle may only be used for private purposes.

The question involuntarily arises, how do color-blind people see a traffic light? This is not a problem, since color blind people do not follow the color, but the switching of the windows that light up.

Therefore, they can accurately determine when to stop and when to start moving again.

Now there are special glasses for driving, but ophthalmologists believe that prolonged wear provokes additional load for eyes. There are also lenses that help to distinguish colors. But at the same time, they make it difficult to perceive other colors.

If a person has a serious form of color blindness, he will need help in choosing an interior and clothes, products. A color-blind person can forget that he sees color incorrectly and get into an awkward situation.

Among the world famous people there were also color-blind people, but their flaw did not prevent them from achieving fame.

French artist Charles Merion, Van Gogh, Vrubel, Savrasov and Repin - they all learned firsthand what colors color blind people see.

True, the last two Russian artists have color blindness due to old age and illness. Repin tried in old age to correct his painting with Ivan the Terrible, but he so distorted the color scheme that the work was stopped.

Once a German ophthalmologist tested the eyesight of 342 artists. Of these, 31 were colorblind. Most of of them went into graphics from her favorite occupation of painting.

Now for a person of art there is a profitable kind of work that is popular - black and white photography.

Do not get hung up on how color blind people see the world. You can always find a common language with them and not focus on his little features.

This will instill confidence in the colorblind and make it clear to him that he is no different from ordinary people. His little "zest" does not cause him physical discomfort, he does not need special care which means he can fully enjoy life.

Useful video about color blindness