About those who are color blind. Color blindness is not a disease, but a feature of vision Famous people suffering from color vision impairment

Contents of the article: classList.toggle()">toggle

Color blindness is the complete or partial inability to distinguish colors.

This pathology is mainly hereditary and is transmitted from women to men.

We will consider below what colors a colorblind person cannot distinguish.

Classification of color blindness

There are two types of color blindness: complete and partial.

Complete (monochromasia, achromatopsia)

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

Partial

Partial is divided into the following types:

Dichromasia (dyschromatopsia), in which one type of cone is not involved in color perception. People suffering from dichromasia are called dichromats. Depending on what type of receptor is damaged, dichromasia is divided into:

Protanopia, in which there is no perception of the red spectrum;
Deuteranopia, in which the perception of the green spectrum is impaired;
Tritanopia, in which the blue part of the spectrum is not perceived.

2. Anomalous trichromasia. This is a condition in which a person's ability to perceive one primary color is reduced (but not completely lost). Similar to dichromasia, there are three types of disorders: protanomaly, deuteranomaly and tritanomaly.

The frequency of occurrence of each anomaly is presented in the diagram:

Depending on the reason for the appearance color blindness happens:

Congenital or hereditary. It passes from mothers to sons. The fact is that the gene leading to color blindness is localized on the X chromosome and is dominant. As you know, the genotype of a man is represented by the XY set, and that of a woman by the XX set. 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 only get sick if both her parents suffer from color blindness. This happens extremely rarely (you can read more about this);
Acquired. Develops as a result of diseases of the optic nerve and retina (diabetic). More often it is unilateral (that is, one eye does not distinguish colors). Acquired color blindness can be reversible (if the underlying disease is successfully treated).

Now let's look at how colorblind people see colors, depending on the type of colorblindness.

Features of dichromasy

Protanopia

Protanopia occurs when red cones are absent or damaged.

This is a hereditary abnormality that affects approximately 1% of all men. At the same time, red colors appear dark gray to a person, violet colors do not differ from blue ones, and orange colors appear dark yellow.

Deuteranopia

Caused by the absence or improper functioning of green cones.

A person cannot distinguish the green spectrum from yellow and orange. The red color is also very difficult to distinguish.

The video below shows how colorblind people with deuteranopia see.

Tritanopia

An extremely rare type of color blindness in which there is no blue pigment. Occurs when the seventh pair of chromosomes is damaged. In this case, blue appears green, purple appears dark red, and orange and yellow appear pink.

Features of anomalous trichromasia

This type of color blindness is caused by congenital abnormalities of the cones. Manifests itself in a modification of the spectral sensitivity of pigments, which manifests itself in a distorted perception of colors.

That is, if dichromats do not distinguish colors at all, then anomalous trichromats have difficulty interpreting their shades.

At the same time, the inability to distinguish some shades with anomalous trichromasia is compensated by an increased perception of other shades. For example, people with protanomaly (the inability to distinguish between shades of the red and green spectrum) distinguish shades of khaki much more clearly. This is not typical for most people with normal color perception.

Treatment of color blindness

If color blindness is inherited, it is almost impossible to cure it using medications, folk remedies or other methods. If the cause of color blindness is an eye injury, then it is possible to cope with it.

But, in any case, color blindness is not a death sentence. There are remedies that can help partially compensate for this problem:

The inability to see colors can be compensated for by observing other people's actions. You can rely on the brightness or location of the object, in which case color detection is not needed.

Also, knowing certain things, such as the arrangement of colors at a traffic light, will make life much easier and help you cross the road without difficulty.

Daily life of colorblind people

Considering all of the above, it becomes clear that colorblind people experience certain restrictions in their social activity. Colorblind people cannot work as sailors, pilots, chemists, military personnel, designers and artists.

Contrary to popular belief, colorblind people can get a license and drive a vehicle. However, the document must indicate that the person cannot work as a driver for hire.

In everyday life, colorblind people face many other difficulties:

If a person who is color blind encounters a page design that does not take into account his potential perception (for example, pink letters on a blue background), then vision does not perceive the written text and the person sees just a gray sheet of paper;
A colorblind person may encounter difficulties when choosing household appliances or a keyboard for a computer if the symbols on the control panel are colored and placed on a dark background;
In schools, children may encounter the teacher writing on the blackboard with colored chalk on a brown or black background, which can cause difficulty for a child with impaired color perception;
Colorblind people often face difficulties when choosing clothes; it is difficult for them to combine colors correctly, because a colorblind person cannot distinguish between them.

You can take a color perception test.

Famous people suffering from color blindness

The most famous person with color vision disorder is John Dalton. It was he who, back in 1794, began to describe this pathology, based on his own feelings.

For some individuals, color blindness has not become an obstacle to creativity. These include the famous artist Vrubel. His paintings lack green and red shades; they are all painted in pearl gray tones.

French painter Charles Merion He was also colorblind, which did not prevent his graphic creations from captivating viewers with their beauty.

It is unknown how the life of the famous singer would have turned out George Michael, if not for color blindness. Since childhood, the artist dreamed of becoming a pilot, and after it was discovered that he was color blind, he began to study music.

Also a famous director is colorblind Christopher Nolan, which did not prevent him from achieving world fame.

How colorblind people see the world photo

Several images of what colors colorblind people see and what the world around them looks like.

Color blindness is the complete or partial inability to distinguish color under normal lighting conditions. The disease affects a significant number of people around the world, although the percentage may vary significantly among different groups. For example, in Australia, 8% of men and only 0.4% of women are color blind. In isolated communities where the genetic pool is limited, a large number of people are often born with this deviation, including its rare variations. Such communities, for example, are the countryside of Finland, Hungary, and some Scottish islands. How colorblind people see 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) and 0.4% of women cannot distinguish red from green or see these colors differently than other people. Very rarely, the disease spreads to shades from the blue spectrum.

Causes of color blindness

How colorblind people see is due to subtypes of the disease, each of which is caused by certain deviations. The most common cause is a malfunction in the development of one or more cone-shaped visual cells, which sense color and transmit information to the optic nerve. This type of colorblindness is usually dictated by gender. The genes that produce photochromic substances are contained on the X chromosome. If some of them are damaged or missing, men are more likely to develop the disease because they only have one of this type of cell. Women have two X chromosomes, so usually the 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 impairments 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 colorblind people see. His study, “Unusual Facts about the Perception of Colors,” was the result of realizing his own illness: the scientist, like some other members of his family, did not see shades from the red spectrum. Colorblindness is generally considered a mild disability, but in some cases it offers certain benefits. Thus, some researchers have concluded that those suffering from color blindness are better able to distinguish camouflage. Such discoveries may explain the evolutionary reason for the high prevalence of color blindness in the red and green spectrum. There is also research suggesting that people with some types of the disease are able to see colors that others cannot see.

Normal color vision

To understand how colorblind people see colors, it is necessary to consider the mechanism of perception in general. The normal retina of the 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. There are usually three types of cones, each containing a specific pigment. Their sensitivity is not the same: one type is excited by a short wavelength of light, the second by a medium wavelength, and the third by a long wavelength, with peaks in the blue, green and yellow regions of the spectrum, respectively. Together they are supposed to cover all visible colors. These receptors are often called blue, green and red cones, although this definition is not precise: each type is responsible for the perception of a fairly wide range of colors.

How do colorblind people see the world? Classification

In the clinical picture, a distinction is made between complete and partial color blindness. Monochromasia, complete color blindness, is much less common than the inability to perceive individual shades. The world through the eyes of a colorblind 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. As for partial color blindness, from the point of view of 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).
**Anomalous trichromasia (tritanomaly).

Types of partial color blindness

In this classification, there are two types of hereditary color vision disorders: dichromasia and anomalous trichromasia. Which colors colorblind people cannot distinguish depends on the subtypes of the disease.

Dichromasia

Dichromasia is a disorder of moderate severity and consists of improper functioning of one of 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 dichromasia based on which type of cone cell is not working correctly:

first: Greek “prot-” - red;
second: “deitra-” - green;
third: “trit-” - blue.

Want to know how colorblind people see? A photo can give a clear idea of the features of their picture of the world.

Forms of dichromasy

Protanopia 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 no different from blue to an individual, but orange appears dark yellow. All shades of orange, yellow and green, whose wavelengths are too long to stimulate blue receptors, appear as a similar yellow tone. Protanopia is a congenital, gender-specific disorder that occurs in approximately 1% of men.
Deuteranopia implies the absence of type 2 photoreceptors, which causes difficulty in distinguishing red and green.
Tritanopia- a very rare disorder characterized by a complete absence of blue pigment. This color appears greenish, yellow and orange appear pinkish, and purple appears dark red. The disease is associated with the 7th chromosome.

What colorblind people see: anomalous trichromasia

This is a common type of congenital color vision disorder. Anomalous trichromasia occurs when the spectral sensitivity of one of the pigments is modified. The result is a distortion of normal color perception.

Protanomaly- an insignificant defect in which the spectral sensitivity of red receptors changes. There is some difficulty in distinguishing between scarlet and green colors. The congenital disease, determined by gender, occurs in 1% of men.
Daytranomaly caused by a similar shift, but in the spectrum of green perception. This is the most common type, influencing to some extent the color discrimination from the previous case. The disorder is hereditary and gender-related and occurs in 5% of European men.
Tritanomaly- a rare disease that affects the discrimination 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 design as dots of a slightly different shade, which can be distinguished by people with normal vision, but not with a certain type of disorder. The full test involves a series of images with different combinations to reveal whether the disorder is present and specifically what colors colorblind people cannot see. For children who do not yet know numbers, drawings with geometric shapes (circle, square, etc.) were developed. Diagnosis of anomalous trichromasia can also be made using an anomaloscope. Currently, there is no effective treatment for color blindness in humans. Colored lenses may be used to improve the ability to see some colors but make it more difficult to see others correctly. Scientists are conducting trials to treat color blindness using genetic engineering methods, which have already yielded positive results in a group of monkeys.

Basically, most colorblind people do not distinguish one of the primary colors - green, red or blue-violet, but it is also possible that a person does not see several colors at once (paired) or does not distinguish any of them (color blindness). At the same time, colorblind people perceive “invisible” colors as gray.

Quite often, a person only accidentally learns about his own color blindness in adulthood. This is exactly how this visual impairment was discovered by the English scientist John Dalton, who did not suspect until he was 26 years old that he could not distinguish the color red. At the same time, his sister and two of his three brothers suffered from color blindness. The term “color blindness” was first used in 1794, when Dalton’s work on his family’s visual illness was published. Dalton's description of this disease was pioneering work and influenced the development of medicine. Over time, this term began to be applied not only to the inability to distinguish the color red, but also to all other color vision disorders.

Causes of color blindness

The reason for the inability to adequately perceive color is a disruption in the functioning of color-sensitive receptors located in the central part of the eye. These receptors are special nerve cells -. In humans, there are three types of cones, each of which is characterized by the content of a color-sensitive protein pigment responsible for the perception of primary color: one type of pigment captures the green spectrum with a wavelength of 530 nm, the second - red with a wavelength of 552–557 nm, the third - the blue spectrum with a wavelength of 426 nm. People who have all three types of pigments in cones and, therefore, normal color perception are called trichromats (from the Greek “chromos” - “color”).

There are two main causes of color blindness: hereditary and acquired pathology.

Hereditary color blindness is a mutation on the female X chromosome. Color blindness is usually inherited from a mother who carries the gene to her son. In men, the gene mutation occurs more often because they do not have an additional X chromosome in the gene set that would compensate for the mutation. However, this does not mean that the mutation gene cannot be inherited by the daughter. According to statistics, the mutation gene occurs in 5-8% of men and 0.5% of women.

Acquired color blindness is not associated with inheritance of the disease. These may be external eye injuries or complications of diseases. The most important areas of damage are distinguished: the retina and the optic nerve. The main causes of acquired color blindness are: age-related disorders, taking certain medications, and eye injuries.

Types of color vision impairment

Normally, humans have three color-sensitive pigments: red, blue and green. People suffering from congenital color blindness (an altered gene is present) have a disruption in the production of one, two, or even all color-sensitive pigments. A person who can distinguish only two primary colors is called a dichromat. Variants of color blindness are distinguished depending on what type of pigment does not work correctly: protanopia - blindness in the red part of the spectrum, tritanopia - blindness in the blue-violet part of the spectrum, deuteranopia - blindness in the green part of the spectrum. In protanopia, red is mixed with dark green and dark brown, and green is mixed with light shades of gray, yellow and brown. With deuteranopia, green is mixed with light orange and light pink, and red is mixed with light green and light brown. If the perception of one color of the spectrum is only reduced, but not completely absent, this condition is called anomalous trichomacy. Depending on the color in which color vision is impaired, these conditions are called protanomaly (weakened red pigment), tritanomaly (weakened blue pigment), and deuteranomaly (weakened green pigment). A complete lack of color vision is achromatopsia. In this case, all colors are perceived as shades of gray, white and black. This pathology is very rare. The most common is protanopia. Tritanopia is extremely rare and is characterized by the perception of all colors of the spectrum as shades of red and green.

Driver's license and other restrictions

In the modern world, there are a large number of markings and signals that use color: signs in public places, road signs and traffic lights, maps, etc. Therefore, people with impaired color vision have a significantly worse quality of life. Color blindness is an obstacle to performing certain professional skills. Therefore, it is significant that people suffering from color blindness have significant limitations in life. They are not allowed to drive commercial vehicles and to work in some professions where correct color perception is extremely important, or the lives of other people depend on it: doctors, pilots, military personnel, sailors, chemists. Representatives of these professions are required to regularly check their vision with an ophthalmologist using special color polychromatic tables.

For the first time, public attention to the problem of color blindness when driving a vehicle was attracted by a train accident in 1875 in Sweden. During the investigation of the incident, it turned out that the driver did not distinguish the color red. After this incident, a color vision test became a mandatory requirement for employment in the transport service.

In Romania and Turkey, driving licenses are not issued to people with color vision impairment. In the countries of the European Union there are no restrictions on the issuance of driver's licenses for color vision impairment. In the Russian Federation, a person with one form or another of color vision impairment can obtain a driver’s license of categories A and B, but with special marks “Without the right to work for hire.” Thus, the driver can only drive vehicles for personal purposes. The issue of permission to drive a vehicle is decided by the ophthalmologist of the driver’s commission.

Color blindness in children

Since this disease has no external clinical manifestations, it can be diagnosed for the first time even in adulthood. Inheritance of color blindness in a family is the first “bell” to check a child for the presence of the disease. Problems with color vision can negatively affect school performance and lead to problems in relationships with peers. The child may not understand what is happening to him and lower his own self-esteem. If anomalies (mutations) are detected, the school teacher should be notified about this. You should choose a place in the classroom where there is no bright light. Ask the teacher not to use certain color combinations when presenting the material: for example, yellow on a green background.

Color blindness test

You can take a color blindness test on our website online in the " " section.

To diagnose color blindness, special polychromatic tables are usually used. There are Rabkin's polychromatic tables and, similar to them, Ishihara's tables. One table for testing color blindness is an image (numbers, shapes or chains) that consists of many small colored circles of the same brightness. The main set usually consists of 27 color tables. A set of 48 tables is intended to clarify the diagnosis. If a person does not distinguish colors, then the table seems homogeneous. People with normal color perception can distinguish shapes, numbers and chains made up of circles of the same color. To check for color blindness using these tables, the following conditions must be met:

The patient should be in a room with natural light, sitting with his back to the window.

The patient should feel relaxed and calm.

The patient is shown each picture at eye level at a distance of approximately 1 m for 5-7 seconds, after which he reports the answer or writes it down on a piece of paper for further verification.

If a personal computer is used to check color blindness at home and the patient cannot distinguish some colors, do not despair. The result also depends on the brightness, color and resolution of the monitor. But it is recommended to see an ophthalmologist.

The inheritance of color blindness can be determined even during intrauterine development. If the inheritance of an anomaly occurs in the family, a woman can undergo special genetic tests: a family history study and a DNA test. It is possible to determine the color blindness gene in which the mutation has occurred using a highly accurate DNA test. However, even if a gene has been identified that has undergone a mutation, it is currently impossible to correct it.

Treatment of color blindness

If the cause of color blindness is a hereditary gene mutation, then it cannot be cured. In the case of treatment of acquired color blindness, sometimes there are positive results when the cause of color vision impairment is completely eliminated. Also, the treatment of acquired color blindness depends on the cause of the disorder. For example, during the natural process of aging with clouding of the lens of the eye, the changes are already irreversible. When taking medications that negatively affect color perception, stopping them can correct the situation. For diseases such as glaucoma, cataracts, and retinopathy, adequate treatment will help restore color vision. And timely diagnosis and treatment at the early stages of these diseases will allow color vision disorders to be completely avoided.

Special glasses or contact lenses can be used to correct color vision. They are painted in a special color. These glasses or lenses will help you see differences between colors, but sometimes they distort objects.

Glasses that block light are useful for color correction because cones work better in dim light. These glasses are equipped with shields or have tinted lenses.

A modern development by US scientists - glasses with multilayer lenses - improve color vision in people with mild color blindness. These glasses allow you to better distinguish between shades of green and red.

Statistics show that color blindness mainly affects men. Why did this attack fall on them? Geneticists claim that these disorders, in their opinion, are caused by a defect in the gene responsible for the perception of the red part of the spectrum. This gene is located on the X chromosome and is responsible for the production of a pigment sensitive to this part of the spectrum. Women, as is known, have a pair of X chromosomes, and men have the first X and the other Y. Therefore, in women, the appearance of a congenital color anomaly is possible only when both chromosomes contain defective genes. This happens very rarely, but a defect in only one X chromosome occurs more often, so men are more likely to suffer from this visual disorder.

It turns out that when a woman distinguishes between raspberry, burgundy and scarlet shades, to a man these colors appear equally red.

So, if the question is: “Darling, how do you like my new pink dress?” - you will hear in response: “Red suits you very well,” don’t be offended. This is not out of harm. A man can also be forgiven for this because the responsibility for the occurrence of color blindness lies with women, since the X chromosome is passed on to the son from the mother, who is a hidden carrier of a defective gene that causes color vision impairment.

People are not only born colorblind, but also become colorblind. You can lose color vision due to a traumatic brain injury, severe flu, stroke or heart attack. There are many colorblind people among the "albinos". The reason for this is the insufficient content of melanin pigment in the retina of “red” eyes. You can temporarily lose color perception during strong motion on an airplane, on a ship or in a car, as well as after severe general and visual fatigue.

In any case, congenital color vision deficiency is not considered a disease. Poor color discrimination does not affect visual acuity in any way. A person may not even realize that he has certain problems, and learn about this peculiarity of his by accident. The Englishman John Dalton, for example, who did not distinguish the color red, did not know about it until he was 26 years old. This happens because colorblind people from childhood learn to call the colors of everyday objects with generally accepted designations. They hear and remember that grass is green, the sky is blue, blood is red. It turns out that colorblind people gradually learn to distinguish colors by degree of brightness, which partly compensates for their deficiency. Moreover, they do this so successfully that only a specialist can expose this roundabout way of perception.

So the lack of normal color vision is not a disaster; this deviation does not affect health. After all, if someone does not have, for example, an ear for music, then the only thing he is not given in this life is studying at a conservatory and a career as a performer. People with impaired color vision see well, but a little differently than others. They may not fear that their vision will deteriorate. Most colorblind people adapt to living normally without any complications.

However, some jobs require very good color vision, such as pilots, and anyone applying for this specialty should undergo a full examination by an ophthalmologist, including a color vision test. Or if a colorblind person has chosen the profession of a chemist or electronics engineer, where mixing up the color of wires or reagents is life-threatening. Being a designer, colorist, botanist, or physician, you may encounter problems that cannot be solved without normal vision.

Drivers suffer the most from color confusion. Until recently, it was believed that being colorblind and driving a car was prohibited. The visual defect was identified (and is still being identified) using special polychromatic Rabkin tables or using a special device - anomaloskoia. A person who was able to distinguish among the same-color background circles numbers or figures made up of circles of the same brightness, but of a different color, received the right to drive. If the test subject's color vision was abnormal, then he should have been denied a driver's license.

These rules were then revised. According to a special order, there are more restrictions on driving a car for people who are blind to certain colors. The only exception is cases when a person who wants to drive a car suffers from complete color blindness, and his work involves the constant transportation of people or valuable cargo.

The highest percentage of colorblind people is registered in the Czech Republic and Slovakia. Scientists have not been able to determine the cause of this phenomenon, just as they still cannot explain another phenomenon; On the Fiji Islands and among Brazilian Indians there are practically no colorblind people.

But on the tiny Pacific island of Pingelap, every 20th resident is completely colorblind (for comparison: the average frequency of colorblindness on Earth is one case per 50 thousand people). This is explained by the fact that during the hurricane of 1775, only two dozen people remained alive on the island. And it had to happen that one of them turned out to be a carrier of the color blindness gene. It was he who awarded it to his descendants, who as a result were all relatives to one degree or another.

Pingelapians do not distinguish not just one, but all colors. In addition, their eyes are not capable of the so-called “sharp” vision that is necessary for reading or any painstaking work, and are painfully sensitive to bright sunlight. During the day, they try to stay in a semi-dark room, because they simply cannot see anything outside. For most of them, the only work available is night fishing.

Having suffered from a serious infectious disease, the father of Russian lyrical landscape Savrasov, towards the end of his life, also stopped distinguishing colors and wrote his last creations from his memories. Vrubel was also color blind. Scientists came to this conclusion after analyzing his paintings, written mainly in pearl-gray tones. The great artist suffered from a lack of perception of red and green colors.

Color blindness or color blindness is not a disease, but a feature of vision when a person cannot distinguish between certain colors and shades. The first widely available description of a type of color blindness was given by John Dalton at the end of the 18th century. From birth, he did not distinguish between some shades of red and green, and realized this only at the age of 26. After which I began to study this topic.

Why can't humans see colors?

Typically, color blindness is a congenital condition that occurs due to genetic defects. But it can also appear throughout life due to diseases of the optic nerve, as well as as a result of age-related changes in the body.

Why is color perception impaired in humans? Color-sensitive receptors are located in the central part of our retina. These are nerve cells that contain several types of color-sensitive pigments: erythrolab, chlorolab and rhodopsin. People with normal color vision have all three pigments in the required quantities in their receptors. In people with color blindness, any of these pigments are affected or absent altogether. The most common defect is the red pigment.

The inheritance of color blindness is associated with defects in the X chromosome and is almost always transmitted from a mother who carries the gene to her son. At the same time, a woman who carries the gene usually sees normally, but her son has a 50% chance of developing color blindness. Color vision disorders are rare in girls - for this, she must inherit defective X chromosomes from both parents.

2-8% of men suffer from varying degrees of color blindness.

Types of color blindness

There are terms that refer to one type or another of color blindness. Protanopia makes it impossible to distinguish green shades from red ones.

With deuteranopia, it is impossible to distinguish green shades from blue ones.

Color blindness in the blue-violet region of the spectrum is called tritanopia and is extremely rare. With this color anomaly, a person is unable to distinguish green shades from blue ones. It is interesting that those who suffer from tritanopia not only cannot distinguish shades of blue, but also have so-called night blindness - they cannot see objects well in the twilight.

There is also a fourth type of color blindness - achromasia. This is the most severe form of deviation, when a person literally perceives the world around him in black and white.

Sharks suffer from color blindness, scientists from the University of Western Australia recently came to this conclusion. These underwater predators see everything around them in black and white.

Diagnosis of color blindness

Testing using Rabkin's polychromatic tables will help make an accurate diagnosis and identify the type of color blindness. These are 27 color tables, which are filled with background circles of equal brightness. Geometric shapes and numbers are made from circles of the same shade. A person with color blindness will not be able to distinguish between them.

How do you know if a child is colorblind?

Determining whether a child has color blindness is difficult because children only begin to meaningfully name colors at around 3 years of age. Until this time, color vision disorders can be diagnosed only by observing the child. For example, he colors pictures in an unusual way: he depicts the grass as brown or red, and the sky as green. There is another interesting way to recognize color blindness in a child. Place identical objects in front of him, for example two candies. They should differ only in colors: one in a gray or black wrapper, the other in a bright one. Usually the child immediately reaches out to the colored one, but if he does not distinguish colors well, he will think about it and then take the candy at random.

If a child incorrectly names primary colors, and considers light green or light pink objects to be white, this is also a reason to suspect color blindness.

How is color blindness treated?

Unfortunately, color blindness cannot be cured. Once upon a time, scientists tried to compensate for the color perception of colorblind people using all kinds of glasses and contact lenses that were colored in a special way. But these attempts were in vain, since scientists only managed to color the image, but at the same time they could not take into account the nuances of the psychophysiology of human color perception.

However, scientists continue to look for methods to treat vision problems such as color blindness. For example, recently, a group of doctors from the University of Washington managed to cure two experimental monkeys from color blindness. During the experiment, scientists introduced a harmless virus carrying in its genome the missing color-sensitive receptor gene into the retina of animals. Both monkeys began to distinguish shades of red and green against a gray background shortly after the procedure.

Scientists have a number of experiments ahead that are designed to prove the safety of this technique for people. Then this method can be used to treat color blindness in humans.

Illustration: thinkstockphotos.com