It is hard to believe that objects and phenomena familiar to us - the red light of a traffic light, the green foliage of a tree or the blue color of ink - can be perceived in any other way. But a person with color blindness can tell that all cats are gray not only at night. Why is this happening and is it possible to fix it? John Dalton, at the age of 26, learned that the color of his jacket was actually burgundy, not gray, and this pathology was named after him.
Description and reasons
Color blindness is a hereditary disorder of the organ of vision that is manifested by a decrease or complete absence of the ability to distinguish colors.
A patient with this diagnosis may not be able to distinguish a particular color or have no color vision at all.
The cause is a gene defect on the X chromosome. Since the gene is recessive, it is suppressed by the healthy gene, if present. If the healthy gene is absent, then there is a disturbance of perception.
Less commonly, the cause of a change in color perception is damage to the retina of the eye, optic nerve, clouding of the lens, traumatic brain injury, a previous viral infection, stroke or heart attack. And also Parkinson's disease, anticonvulsants, Kallman syndrome.
Men are more likely to be color blind than women. Only 1% of women are color blind, while 8% of men have this problem. This is due to the fact that the gene is localized on the sex chromosome (in the X chromosome). And since men have only one, and women have two, then in the presence of a defect, the chromosome cannot overlap with another healthy gene. And it manifests itself in a decrease in color sensitivity.
How does color perception work?
There is a three-component theory.
In our color-perceiving membrane - the retina - there are special cells - cones. They are divided into three types, each of which is responsible for the perception of its own light spectrum - blue, red, green. These are the primary colors and any other shade can be obtained by mixing these three. Reflecting from the object we are looking at, the light hits the cones. Depending on the spectrum, certain types of cones are excited and transmit information to the brain for processing, where the perception of the surrounding world takes place.
Color blindness unites a group of perception disorders. There are several types of color blindness.
Disease types First
and the most common is an abnormal perception of one of the three colors. This anomaly can be of varying severity, and depending on this, three types are distinguished. Reduced perception of red color protnomaly, green - deuteranomaly, blue - tritanomaly. Such names came from the distribution of colors in order. The first, in Greek "protos" - the designation of red, green, "deuteros" - the second, blue, "tritos" - the third. Second type
characterized by complete lack of perception of one color. Since this color is present in the composition of other colors, their perception also changes, but to a lesser extent. People with this pathology are called protanopes, deuteranopes and tritanopes. Third type
- monochromaticity - is extremely rare. With this pathology, the patient perceives only one of the three primary colors. And the fourth type
, the rarest and most unpleasant - complete color blindness - achromasia. Occurs with gross violations of the cone apparatus. At the same time, a person literally sees the world in black and white. In one of his books, the writer Oliver Sachs wrote about an entire island inhabited by such people.
Diagnosis of color blindness
Most people can adapt to the abnormality. An early diagnosis will help you choose a profession that is not related to accurate color perception.
Early diagnosis of color blindness in children is especially important. timely assistance will help prevent learning problems during school years, because many school materials are highly dependent on color perception.
On examination by an ophthalmologist, the patient is shown various color pictures, which depict numbers or geometric shapes. And already focusing on the patient's responses, the doctor differentiates with the pathology of which types of cones the violation is associated. These are the tables of Rabkin and Ishihara.
Another method is more objective — electroretinography. It allows you to identify a violation in young children who cannot respond to test pictures. This method evaluates the electrical activity of the retina. At the same time, they shine red, blue or green in the eyes to examine the response level of electrical activity. If it is reduced or absent, then this type of cones has a defect.
Is Color Blindness Treated?
A person's hereditary form of color blindness has no cure. But research and experiments aimed at completeness of color perception have been going on for a long time. Back in 2009, scientists at the University of Washington, using gene therapy, returned the perception of red and green colors to monkeys. While the results look promising, treatments are not applicable to humans until proven to be absolutely safe.
The acquired form of color blindness is subject to treatment, however, full correction of color perception cannot be achieved in most cases.
- Special glasses and contact lenses are an excellent solution for correcting color blindness. These methods can significantly improve the quality of life, and in some cases restore color perception to almost full extent!
The most popular product on the Russian market is EnChroma glasses. According to the manufacturer, tinted lenses in EnChroma glasses include a patented light filtering technology that allows people with altered color perception to see a wide range of colors.
Also, since 2017 in Russia, it is possible to pick up glasses if perception is impaired in the red or green spectrum. Pilestone glasses are of two types. High contrast and casual, differing in the degree of color correction and contrast.
- It is important that all of these models have passed the FDA control (i.e. recognized as safe by the Medical Device Safety Supervision Service).
Soft contact lenses
More recently, soft contact lenses have appeared to correct color vision abnormalities. The principle of operation is similar to spectacle color blindness correction. There is a special layer on the lens to enhance color perception. Some areas of the lens are colored with dyes that absorb light waves of the required length. As a result of this absorption, the perception of red and green colors is enhanced. The lens material must meet certain requirements: high gas permeability, elasticity and softness, good patient tolerance.
It is important to understand that the selection of correction methods should be carried out by an ophthalmologist or optometrist, the final result depends on this. With the right choice, the perception of colors will be maximized and will significantly improve the quality of life!
- Interesting Facts
- Most applications and operating systems are not in vain made in blue and blue colors. After all, it is this spectrum that is best defined for various types of color blindness.
- The researchers found that color blind people see camouflage fabric better, so it is possible that people with these qualities will be accepted into the reconnaissance troops.
Famous color blind people have great painters. Van Gogh, for example, did not accidentally use so much yellow in his canvases. And many researchers of the work of the Russian artist Vrubel come to the conclusion that the creator had a violation of the perception of red and green colors, which is why the paintings are of such restrained tones.
Color blindness does not affect the clarity of vision, but with a significant violation of color perception, it impairs the perception of surrounding information.
With proper observation, timely diagnosis and correction, the patient will be able to regain the bright colors of life! Take care of your eyes!
With color blindness (color blindness), a person is not able to distinguish shades of different colors: most often - red, green and blue. The main cause of the condition is a lack of light-sensitive pigments in the retina. In this article, we will look at how genetics affects color blindness and what types of it are identified by experts.
Does gender matter?
It is believed that color blindness occurs primarily in men. And this is true: worldwide, 1 in 12 men and 1 in 200 women suffer from color blindness. This is primarily a hereditary disease, that is, it occurs due to genetics.
- How it works? The gene for red-green color blindness is an X-linked recessive gene. X-linked recessive genes manifest themselves if they are present on both X chromosomes in women and on one X chromosome in men. I.e:
- a child born to a woman needs to inherit two X chromosomes with a carrier gene in order to be born color blind;
a male child needs to inherit only one X chromosome with a carrier gene in order to develop color blindness;
That is why the disease is not common among women: the likelihood that a woman will inherit both genes necessary for color blindness is quite low.
Types of color blindness
- We talked about the symptoms and mechanism of the disease in this article. Understanding the types of color blindness: Red-green color blindness. This is the most common form and makes it difficult to tell red from green. Among them there are protanomaly (red is more like green) and deuteranomaly
- (green looks more like red). The combination of these 2 subtypes does not allow a person to distinguish red from green at all. Blue-yellow color blindness ... A much less common form that affects the perception of 4 colors at once. With tritanomaly blue and green look the same, while yellow and red look similar. Because of tritanopia
- it is difficult to distinguish between several shades associated with blue and yellow (green, purple, red, pink, and others). Complete color blindness or achromatopsia
... It is extremely rare and results in monochromatic or completely colorless vision. This form is the hardest to adapt to.
There are two reasons for the appearance of color blindness:
Color blindness is linked to the X chromosome and is transmitted from the carrier mother to the children. There are often cases of congenital distortion of the perception of some colors, but at the same time the patient can recognize and distinguish other colors and shades that are difficult to distinguish for an ordinary person. Read about cases of color blindness in women in this article.
Color blindness develops against the background of damage to the retina and optic nerve.
- In the center of the retina there are special cells whose main function is to perceive color. These cells are called cones. Three types of cones are involved in the retina, each of which contains a protein substance (pigment) that captures its own genetic inherent color: green, red or blue. The cones of a healthy person contain all three pigments. In pathology, cones are devoid of pigment or it is defective.
Optic nerve pathology
- With neuritis and optic nerve atrophy, a decrease in color perception occurs, depending on the degree of damage to the optic analyzer.
- Age-related visual impairment associated with clouding of the lens
Consequences of taking certain medications (digitoxin, ibuprofen)
The use of drugs based on digitalis causes visual impairment due to its accumulation in the blood plasma and retina. Statistics say that 25% of cases of side effects of digitaloxin intake are manifested in visual disturbances and color perception (the appearance of blue-yellow or red-green spots in front of the eyes, luminescence of objects with shades of yellow).
How is color blindness inherited?
Color blindness is inherited and manifests itself only in men. This is due to the fact that the gene for color blindness is linked to the X chromosome. As you know, female chromosomes are represented as XX, and male chromosomes as XY. It follows from this that the defeat of the X chromosome in men inevitably causes the disease, while the defeat of the female X chromosome is compensated by another X chromosome, so the disease does not manifest itself. A woman acts as a carrier of the disease, which she passes on to her children through the genotype.
, , 
Many color-blind people will not see the number 83 in this image.
People with protanopia will not see the number 37
People with deuthanopia will not see the number 49 (or 44)
People with tritanopia will not see the number 56 Color blindness
, color blindness is a hereditary, rarely acquired feature of vision, expressed in the inability to distinguish one or more colors. Named after John Dalton, who first described a type of color blindness based on his own feelings, in 1794.
History of the term Dalton was protanopus
(could not distinguish red), but did not know about his color blindness until the age of 26. He had three brothers and a sister, and two of the brothers suffered from red color blindness. Dalton detailed his family vision defect in a small book. Thanks to his publication, the word "color blindness" appeared, which for many years became synonymous not only with the anomaly of vision in the red region of the spectrum described by him, but also with any violation of color vision.
Cause of color vision disorders In humans, in the central part of the retina are located color-sensitive receptors - nerve cells called cones. Each of the three types of cones has its own type of color-sensitive pigment of protein origin. One type of pigment is sensitive to red with a maximum of 552–557 nm, another to green (maximum about 530 nm), and the third to blue (426 nm). People with normal color vision have all three pigments (red, green and blue) in the cones in the required amount. They are called trichromats (from ancient Greek. χρῶμα
The hereditary nature of color vision disorders
The transmission of color blindness by inheritance is associated with the X chromosome and is almost always passed from the mother carrying the gene to the son, as a result of which it is twenty times more likely to manifest itself in men with a set of XY sex chromosomes. In men, a defect in a single X chromosome is not compensated, since there is no “spare” X chromosome. 2-8% of men suffer from varying degrees of color blindness, and only 4 women out of 1000. For the manifestation of a visual impairment in a woman, a rather rare combination is necessary - the presence of a mutation in both X chromosomes. The manifestation of color blindness of this type is associated with a disruption in the production of one or more light-sensitive pigments in the optic receptors of the cones.
Some types of color blindness should not be considered a "hereditary disease", but rather a feature of vision. According to research by British scientists, people who find it difficult to distinguish between red and green colors can distinguish many other shades. In particular, shades of khaki, which appear the same to people with normal vision. Perhaps in the past, such a feature gave its carriers evolutionary advantages, for example, it helped to find food in dry grass and leaves.
Acquired color blindness
This is a condition that only develops in the eye where the retina or optic nerve is affected. This type of color blindness is characterized by progressive deterioration and difficulty in distinguishing between blue and yellow colors.
It is known that IE Repin, being in old age, tried to correct his painting “Ivan the Terrible and his son Ivan on November 16, 1581”. However, others found that due to color vision impairment, Repin greatly distorted the color scheme of his own painting, and the work had to be interrupted.
Types of color blindness: clinical manifestations and diagnosis
Color blindness in the blue-violet region of the spectrum - tritanopia, is extremely rare and has no practical value. In tritanopia, all colors in the spectrum are represented by shades of red or green.
- Clinically distinguish between total and partial color blindness. Less often, there is a complete lack of color vision. .
- Partial color blindness
- Red receptors are disrupted - the most common case
- Protanopia (protanomaly, deuteranomaly)
- Blue and yellow parts of the spectrum are not perceived
- Dichromia - tritanopia (tritanopia) - lack of color sensations in the blue-violet region of the spectrum.
- Deuthanopia - green color blindness
Anomalies in three colors (tritanomaly)
The nature of color perception is determined on special Rabkin's polychromatic tables. The set contains 27 colored sheets - tables, the image on which (usually numbers) consists of many colored circles and dots that have the same brightness, but slightly different in color. For a person with partial or complete color blindness (color blindness), who cannot distinguish some colors in the picture, the table appears to be uniform. A person with normal color perception (normal trichromat) is able to distinguish numbers or geometric shapes made up of circles of the same color.
Dichromats: distinguish between the blind to the red color (protanopia), in which the perceived spectrum is shortened from the red end, and the blind to the green color (deuteranopia). With protanopia, red is perceived as darker, mixed with dark green, dark brown, and green with light gray, light yellow, light brown. With deuteranopia, green is mixed with light orange, light pink, and red with light green, light brown.
Occupational Limitations in Weakening Color Perception
Color blindness can limit a person's ability to perform certain professional skills. The vision of doctors, drivers, sailors and pilots is carefully examined, since the lives of many people depend on its correctness. The color vision defect first attracted public attention in 1875, when a train crash occurred in Sweden, near the city of Lagerlund, resulting in heavy casualties. It turned out that the driver could not distinguish red, and the development of transport at that time led to the widespread use of color signaling.
This catastrophe led to the fact that when applying for a job in the transport service, they began to evaluate color perception without fail.
Features of color vision in other species
The visual organs of many mammalian species have limited ability to perceive colors (often only 2 colors), and some animals, in principle, are not able to distinguish colors. See the article Vision for more details. On the other hand, many animals are better able than humans to distinguish the gradations of those colors that are important to them for life. Many representatives of the order of equids (in particular, horses) distinguish shades of brown that seem to be the same to a person (it depends on whether this leaf can be eaten); polar bears are able to distinguish shades of white and gray more than 100 times better than humans (when melting, the color changes, you can try to conclude from the shade of color whether an ice floe will break if you step on it).
- Literature Kvasova M.D.
- Vision and heredity. - Moscow / St. Petersburg: 2002. Rabkin E.B.
Polychromatic tables for the study of color perception. - Minsk: 1998.
Color blindness, which is characterized by an inability to recognize certain spectra of colors, is called color blindness. Basically, this pathology is inherited and manifests itself in childhood. There are color blindness and acquired. We will find out in what forms this disease develops, why it occurs and whether it can be cured.
Color blindness - what is this disease?
Color blindness, or color blindness, is a visual impairment, namely the function of color perception. With this pathology, a person does not distinguish one or more colors. For their perception in the eyeball, cones are responsible - photoreceptors located in the macula - the central part of the retina. There are 3 types of cones, each containing red, blue, or yellow protein pigments. Actually, these are the main shades, the mixing of which forms many other tones. In the absence of one or more pigments, color perception is impaired.
Why does color blindness occur?
Congenital color blindness, which is diagnosed in most cases, is inherited. The transmission of the color blindness gene is associated with the X chromosome, the carrier of which is the mother. She can pass this gene on to her baby while staying healthy.
Acquired color blindness develops with eye injuries, as well as pathologies of the organs of vision and the central nervous system with damage to the optic nerve. Color blindness is not an independent disease. So, with cataracts, characterized by clouding of the lens, light does not penetrate well through the structures of the optical system of the eyeball, as a result of which the ability of photoreceptors to perceive colors is impaired. When the optic nerve is affected, all functions of the eye that are responsible for vision are impaired. Color perception is also impaired, and the condition of the cones may be normal. Disruptions in the transmission of nerve impulses to photoreceptors can also occur with such ailments as Parkinson's disease, cancer, and stroke.
Sometimes color blindness is a side effect of certain medications, but this does not happen very often. Color blindness can spread to one or both eyes, with different damage to the photoreceptors of each. One eye with color blindness can perceive colors better than the other.
Clinical classification of color blindness by color
As noted, color blindness develops unevenly. This disease can take various forms. Depending on the absence of certain photoreceptors, the perception of certain shades is impaired. Normal color perception is called trichromatic, when in a person, trichromate, all three types of protein pigment function in the macula. There are three types of color blindness: Achromasia - absolute inability to distinguish colors. The only shade a person sees is gray. This form of pathology is extremely rare. Monochromasia - color blindness, in which only one color is perceived. As medical practice shows, this disease is accompanied by photophobia and nystagmus. Dichromasia
- - a type of color blindness, which is characterized by the ability to distinguish between only two spectrum of colors. This form of color blindness is divided into subtypes:
- Protanopia is a violation of the perception of red color. Usually, the patient confuses this shade with brown or dark green, green is perceived as light gray, and yellow as light brown.
- Deuteranopia is the inability to distinguish green from other spectra. It mixes with orange and yellow, while red appears as light green or light brown. Pathology is diagnosed in only 1% of patients with color blindness.
Tritanopia is the absence of blue and violet shades in the human perceived color spectrum. The patient sees almost everything in green or red tones. As a rule, with tritanopia, there is poor twilight vision.
How is color blindness manifested?
Visual acuity with color blindness does not suffer, so it is impossible to diagnose it by this parameter. Actually, this pathology may not appear for several years, if we are talking about its congenital form. It is possible to detect color blindness in a child only when he ceases to bind each color to a specific object. For a child in childhood, a tree can be green, and the sky can be blue. The kid does not project this information onto other objects and does not complain to his parents about the violation of color perception, even if it is.
Parents can accidentally notice this in their child, drawing attention to mistakes in the names of flowers. However, the first test of vision, including color perception, is carried out in kindergarten. During the examination, the ophthalmologist should notice signs of color blindness.
- Acquired color blindness is identified by a number of symptoms, many of which are subjective. A person may turn to an ophthalmologist with complaints about:
- inability to distinguish colors;
- impaired perception of one, two or three primary colors of the spectrum;
- photophobia, which is accompanied by tearing and pain in the eyes;
twitching of the eyes, which indicates the development of nystagmus.
How is color blindness detected?
the ophthalmologist prescribes a polychromatic test using Rabkin tables to check color perception. This test consists of 27 main and several additional pictures, which depict geometric shapes, numbers, numbers and other symbols, painted in different tones. Perhaps, such pictures are remembered by every person who was examined by an ophthalmologist. The symbols on them consist of many small circles of different shades, the background is also composed of these multi-colored circles.
The doctor shows the card to the patient, who must name the symbol shown in the picture. The subject is given no more than 5 seconds to think. 27 cards are used to identify color blindness and its type. An additional two dozen pictures allow you to determine the degree of development of pathology. Also, thanks to the polychromatic tables, you can find out the causes of the disease.
In addition to the Rabkin test, the Ishihara test is used to diagnose color blindness. It is only suitable for patients who can read. Sometimes color blindness develops with mental retardation. The Ishihara test is contraindicated in such patients. To pass it, you need to be able to read and understand what you are reading. The test is a letter written in red spots.
How is the color perception test done?
- In order for the test results to be accurate, the following conditions must be met:
- eyesight is checked for color blindness in natural light;
- it is impossible that direct sunlight falls on the cards, in addition, they should not blind the patient;
- the person being tested should feel good, if he is sick, feeling unwell, the test results will be unreliable;
- tables are located at a distance of one meter from the patient, right at eye level;
the picture is displayed for no more than 5 seconds. This time is quite enough for a healthy person to examine the symbol on the card.
If a person is completely healthy, he will correctly name more than 90% of the characters. With color blindness, the patient gives no more than 25% of correct answers.
Can color blindness be cured?
If color blindness develops against the background of any acquired pathology, for example, cataracts, then the underlying disease is treated. Its complete cure normalizes color perception.
As for hereditary color blindness, today it is not treated. There are attempts to introduce viral particles into the abnormal gene, which would change it. While such technologies are at the development stage. They do not apply to humans.
At the same time, color blindness, due to which a person does not distinguish almost any colors, is rare. In most cases, a color blind person can see normally, limited to those spectra that are available to him. This does not cause much discomfort in life. It all depends on the type of color blindness and its degree.
Can color blindness be prevented?
Color blindness is inherited. The gene for this disease is passed on by the mother. Modern technology makes it possible to find out if a child will have color blindness. To do this, you need to carry out a genetic test (DNA testing). With the help of this study, it is possible to identify a mutated gene, but it is not possible to change it. Therefore, such an expensive procedure is of no practical importance. Color blindness is a form of color blindness
, mainly congenital visual pathology, in which the patient does not distinguish between the colors of the surrounding objects.
We feel all the richness of shades due to the presence of light-sensitive cells in the retina.
With color blindness, the patient may not notice the juicy green grass, the endless blue sky, red strawberries, and so on. In the rarest of cases, the patient can see the world as in black and white cinema. People who are color blind are called color blind.
Color blindness and normal vision Color blindness refers to the inability to sense one of the main colors. Instead, he sees gray ... For the first time this disease was identified and analyzed in detail by the Englishman D. Dalton. He suffered from this disease and could not even suspect that he did not distinguish green from red.
In his scientific work, he introduced the term "color blindness" into scientific circulation, as the eye's immunity to a reaction to light rays of different lengths. The mesh contains light-sensitive elements. Rods form achromatic (i.e. two-color black and white) vision in humans. There are 3 types of cones, i.e. which respond to red, blue and green rays, respectively.
They contain a suitable pigment that reacts to light waves of different wavelengths.
Color blindness occurs when one or more substances responsible for color vision are not found in the cones. Sometimes cones contain the necessary substances for color perception, but there are not enough of them for a person to feel colors sufficiently. The development of an inherited disease is not associated with progression. The intensity of the disturbance in color perception remains the same throughout life ... But acquired color blindness can gradually worsen, causing a noticeable drop in visual acuity.
Worst of all, a person suffering from acquired color blindness distinguishes between yellow and blue color rays. Sometimes after injuries there is a complete loss of color vision.
- Depending on what colors the patient does not distinguish, the following types of color blindness are distinguished: Protanopia
- - this is the inability to feel the red color. The mutation is the most commonly diagnosed. Deuteranopia
- Is green blindness. Tritanopia
- - absolute inability to distinguish colors. The only shade a person sees is gray. This form of pathology is extremely rare. - this is the impossibility of feeling blue or purple.
- As noted, color blindness develops unevenly. This disease can take various forms. Depending on the absence of certain photoreceptors, the perception of certain shades is impaired. Normal color perception is called trichromatic, when in a person, trichromate, all three types of protein pigment function in the macula. There are three types of color blindness: Is the feeling of only one color.
- - this is a complete inability to feel colors (complete color blindness). Abnormal trichromasia
- this is a case of reduced activity of red, green or blue pigment.
Causes Color blindness occurs as a result of unfavorable heredity or due to acquired dysfunction of eye receptors
... It is inherited in a recessive manner. In the case of unfavorable heredity, the disease can sometimes arise as a result of a mutation. The hereditary type of the disease is associated with the pathological structure of the X chromosome. It has a set of genes necessary for the presence of light-sensitive pigment in sensitive cells.
Provided that color blindness is innate, color perception is absent in both eyes. The pathological gene is inherited and manifests itself in grandchildren and great-grandchildren.
- Reasons for new-on color blindness:
- eye pathologies that affect the retina and optic nerve;
- complications of diseases of the nervous system;
- diabetic macular degeneration;
- eye injury;
- ultraviolet damage to the retina;
- pathologies that develop with age;
taking certain medications.
Acquired color blindness often develops in one eye (if an injury or disease is a factor in its development). This disease gradually progresses. The disease is most often diagnosed in men. In women, it is found extremely rarely.
This is due to the X chromosome, to which the gene is linked, which is responsible for determining the production of pigments important for color vision. If a man is color blind, he will pass it on to his daughter. A girl may have two chromosomes linked to a gene that is responsible for carrying the disease. Then she, too, will suffer from color blindness.
- Signs of color blindness depend on which types of cones do not distinguish between light waves: With protanopia
- all red-colored objects appear gray, black, brownish, sometimes dark green. Such people see green as gray or light brown. With deuteranopia
- the person sees orange or pink instead of green. Such a patient does not feel red: it seems brownish to him. With tritanopia
- a person sees red and green colors and all their shades. However, instead of blue or purple, he will see pink. There is no twilight vision in patients suffering from tritanopia. With monochromaticity
- a person can distinguish only one color. This rather rare variant of the disease is accompanied by photophobia. In case of achromasia
- a person sees only white, black and all shades of gray.
Almost all people with color blindness have poor vision. This creates additional inconvenience in everyday life.
Parents may sometimes be unaware that a child has color blindness. Careful observation of how a child works with colored plasticine or paints sometimes gives rise to a visit to a doctor for color blindness.
Due to impaired color perception, a child may suffer in a children's team. Some children change their perception of the world, their self-esteem decreases. The child needs to be told that he is color blind and sees the world differently from others. But that doesn't make it any worse.
Color blind people have difficulty driving. A color blindness test is required to obtain a driver's license. In a number of countries, a color blind person obtains a driver's license, but they note that he cannot be a driver.
Anomalies in three colors (tritanomaly)
A color blind person cannot work as a chemist, surgeon, pilot, sailor. Separate signs, signs complicate the life of people suffering from the disease in question. Congenital disease is difficult to diagnose in childhood.
Many patients find out that they are color blind only during a physical examination. The diagnosis of childhood color blindness is associated with certain difficulties. This is due to the fact that the child masters colors by about four years old. But in this case, he uses learned data.
(for example: the sky is blue, the strawberry is red). But how he actually sees objects, adults do not know. The easiest way to diagnose color blindness at home is to invite your child to draw what he sees outside the window.
And from the results, you can see how accurately the baby perceives colors. Color blindness may be indicated by the replacement of paints (for example, red - for brown). This suggests that the child is confusing colors. The most common and simple color blindness test is done using Rabkin tables. The set includes 26 different tables. With their help, you can easily diagnose color blindness. Numbers or pictures are printed on them in the form of small circles. They are made in different color combinations. A person without color blindness can easily determine what is drawn.
A color blind person will indicate images of only those colors that are available for perception.
- For an adequate examination, you need:
- natural lighting;
- dim light;
placing a light source behind the patient's back.
The table is shown at eye level at a distance of approximately 1 meter. People with normal vision read all tables.
In addition to determining color blindness using the tabular method, the Holmgren method is used. It is based on the fact that the patient is asked to place skeins of yarn of different colors.
If it is impossible to diagnose a color vision disorder using the tabular method, they resort to spectral analysis.
Congenital color blindness cannot be cured. It is corrected with the use of certain types of glasses or lenses. The effectiveness of the correction depends on the type of color sensation disorder. Secondary color blindness in some cases is amenable to therapy. The etiology of the disease is of decisive importance for the choice of therapy.
- An experienced ophthalmologist provides advice on this matter:
- with the pathological effects of medications, it is advisable to stop their use;
- with cataracts, which led to a violation of color perception, an operation is prescribed;
with age-related loss of color vision, the pathology does not respond to therapy. Sometimes, when color perception is impaired, wearing special glasses is recommended. They obscure bright light, which makes the patient better distinguish colors. The glasses have lenses of tinted color and corrective elements located on the side.
High-quality foreign optics almost 100% correct mild forms of the disease. The person's ability to perceive green, red is best corrected.
VIDEOColor blindness is not a defect, but just one of the features of human vision, due to which color discrimination is lost. A person often experiences discomfort in everyday life. It is forbidden to engage in some professions with color vision disorders. To prevent the development of eye diseases, vision correction is indicated.
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What else to read
What is color blindness? Color blindness
is the result of the absence or failure of certain color-sensitive cells in the retina.
The retina is the layer of nerves at the back of the eye that converts light into nerve signals that send information to the brain. A person with color blindness has trouble distinguishing between colors such as red, green, blue, or a combination of these colors.
Usually, the eye has three types of cone cells, which are light-sensitive cells and are located in the retina. Each type is sensitive to red, green, or blue light. You can see, distinguishing colors when your cone cells distinguish between the number of cells of these three primary colors. When one or more of these types of cells is missing or unable to function properly, you are unable to see one of these three colors, or you may see a change in one color or another.
The cone cells are concentrated mainly in the central part of the retina (macula) to provide clear, sharp color vision. They work best in relatively bright light, so it is difficult to distinguish colors in dim light.
The term "color vision problem" is often used instead of color blindness because most people with color blindness can distinguish slightly between colors. Some people with color blindness are unable to distinguish colors at all.
What are the causes of color blindness?
Most color-related vision problems are genetically inherited and present from birth. Other color vision problems are caused by the aging process, disease, eye injury (acquired vision problems), optic nerve problems, or side effects of certain medications.
Inherited color vision problems are more common than acquired vision problems and affect men much more often than women.
How is color blindness diagnosed?
Various tests are used to measure the ability to distinguish colors:
The most famous test is the pseudo-isochromatic plate test. During this test, you are asked to look at a collection of colored dots and identify a pattern such as a letter or number. The type of color vision problem you have can often be determined by what patterns you see or cannot see with the various plates used during the test. For people with acquired color vision problems, a color distribution test is used. This test is based on the distribution of objects according to color or shade. People who are color blind cannot arrange the color plates correctly.
How is it treated?
Inherited color vision problems cannot be cured or corrected. Some acquired color vision problems can be treated, depending on the cause. For example, if a cataract is causing color vision problems, cataract surgery can restore normal color vision.
A color vision problem can have a significant impact on a person's life. These problems can affect the ability to learn and read, as well as significantly limit the choice of a person's profession. However, children and adults with color vision problems can learn to compensate for their inability to distinguish colors.
Signs of color blindness can vary. Different people see different shades of colors. You are unable to see red, green, and blue colors, or shades of those colors. If your color vision problem is less severe, you may not realize that you are seeing something other than someone with normal color vision.
People with less severe color vision problems can distinguish shades of colors. They may not be able to distinguish red from green, but they can see blue and yellow.
People with severe color vision problems cannot distinguish color at all. They only see shades of gray, black, and white. Inherited color vision problems
affect both eyes equally; Acquired color vision problems
may occur in only one eye, or may affect one eye more than the other.
Inherited color vision problems are usually present at birth and do not change over time.
Acquired color vision problems can change over time as the person ages or as the disease progresses.
Genetically inherited color vision problems.
Most of the problems associated with color vision are inherited genetically and are related to problems with the cone cell in the eye, which distinguishes color. Inherited color vision problems affect both eyes equally, are usually present from birth and do not change throughout a person's life.
The most common color vision problems are inherited problems that make it difficult to distinguish between red and green.
This problem affects about 8% of men and less than 1% of women. It is quite rare that there is a type of inherited problem in which a person sees blue and yellow shades the same way (both men and women).
Types of inherited color vision problems.
There are four main types of inherited color vision problems: The most common type of color vision problem called abnormal trichromasia
, occurs in people who have all three types of cone cones (in order to distinguish between red, green, or blue), but one type of cone cone is missing or has the wrong number, or one type of cone lacks pigments to perceive color.
People with these vision problems can see all three colors, such as green, red, and blue - but not in the same way as people with normal color vision. Thus, they see different shades of colors differently than people with normal color vision. Another type of color vision problem called dichromasia
occurs when one of the three cone types is missing. Thus, a person can only see two of the three colors.
Most people with this color vision problem can tell the difference between blue and yellow, but have trouble distinguishing between red and green. (Very few people in this category can see red and green, but cannot distinguish between blue and yellow.)
People with this type of the disease have more serious color vision problems than the first type (abnormal trichromasia). A third type of inherited color vision problem called blue cone monochromatic
, occurs when two of the cone cones (red and green) are missing.
This type of inheritance only affects boys and men. Distance vision is often impaired, and boys with this condition may have involuntary eye movements ( )
A boy or a man with a blue cone monochromaticity distinguishes only blue colors from the entire spectrum of colors. The fourth and main type of inherited color vision problem called achromatopsia
, occurs when all three types of cones are missing.
A person with this color vision problem cannot see the color spectrum, but only shades of gray, black and white.
People who have this type of disease may also have other vision problems, such as poor vision at a distance and when reading, sensitivity to light and light (photophobia).
This type of color vision problem is the rarest and most serious.
This disease is also called monochromacy of the retinal rods, because a person sees mainly due to the rods of the retina.
The genetics of inherited color vision problems.
Most color vision problems are associated with genes that regulate the production of pigments in the color-sensing cone cones.
The genes for the cone cones, which are responsible for the perception of red and green colors, are found on the X chromosome. Females have two X chromosomes. Males only have one X chromosome and a Y chromosome, and they will inherit their X chromosomes from their mother.
A man will have a color vision problem in the red-green range if the defective gene is on his only X chromosome. A woman may have a defective gene on one of her two X chromosomes that can cause color vision problems, and this happens much less frequently than men.
A woman who has the genome for this type of color vision problem has a 50% chance of passing this gene on to her sons (because they will inherit one of the two X chromosomes). Her daughters may have this kind of problem if they inherit a defective gene on the X chromosome from both mother and father. This is a much less likely case.
This is why color vision problems can occur over generations in families that have a genetic predisposition to color vision problems.
The genes for the retinal cone pigment and for seeing blue colors are not on the X chromosome, but on the non-sexual chromosome that both men and women have. This means that color vision problems associated with blue are equally common in both men and women. However, these types of color vision problems are relatively rare.
Acquired color vision problems.
Acquired color vision problems have many causes:
Aging can increase the chance of color vision problems. As a result of the darkening of the lens with age, people find it difficult to distinguish between dark blue, dark green and dark gray.
Side effects of certain medications can cause temporary or permanent color vision problems.
Certain eye conditions such as glaucoma, macular degeneration, cataracts, or diabetic retinopathy can cause temporary or permanent color vision problems. Treating these conditions can help maintain or restore color vision.
A wound in the eye, especially in a part such as the retina (spot), or in the area of the optic nerve, can cause color vision problems.
Acquired color vision problems:
They occur in women as often as in men. Inherited color vision problems are much more common in men.
May occur in only one eye or affect one eye more than the other. One eye may have a color vision problem while the other eye may have normal color vision.
May change over time, over a person's life, or during the illness or injury to the eye that causes the problem.
What is color blindness? Often deprives a person of the ability to distinguish between blue and yellow.
- This is a congenital, less often acquired pathology of vision, characterized by abnormal color perception. Clinical symptoms depend on the form of the disease. Patients lose their ability to distinguish one or more colors to varying degrees. Diagnosis of color blindness is carried out using the Ishihara test, the FALANT test, anomaloscopy and Rabkin's polychromatic tables. No specific treatment methods have been developed. Symptomatic therapy is based on the use of glasses with special filters and contact lenses to correct color blindness. An alternative option is to use special software and cybernetic devices to work with color images.
What is color blindness?
Color blindness, or color blindness, is a disease in which the perception of color by the receptor apparatus of the retina is impaired while maintaining normal indicators of the remaining functions of the organ of vision. The disease was named after the English chemist J. Dalton, who suffered from a hereditary form of this disease and described it in his works in 1794. Pathology is most common among males (2-8%), occurs only in 0.4% of women. According to statistics, the prevalence of deuteranomaly in men is 6%, protanomaly - 1%, tritanomaly - less than 1%. The most rare form of color blindness is achromatopsia, which occurs with a frequency of 1: 35,000. It has been proven that the risk of its development increases in the case of closely related marriages. The large number of consanguineous married couples among the inhabitants of the island of Pingelape in Micronesia was the reason for the emergence of "a society that does not distinguish between colors."
Causes of color blindness
The etiological factor of color blindness is a violation of color perception by the receptors of the central part of the retina. Normally, three types of cones are distinguished in humans, which contain a color-sensitive pigment of a protein nature. Each type of receptor is responsible for the perception of a specific color. The content of pigments, capable of responding to all spectra of green, red and blue, ensures normal color vision.
The hereditary form of the disease is caused by a mutation of the X chromosome. This explains the fact that color blindness is more common in men whose mothers are conductors of the pathological gene. Color blindness in women can be observed only if the father has the disease, while the mother is the carrier of the defective gene. With the help of genome mapping, it was possible to establish that mutations in more than 19 different chromosomes can cause the disease, and also to identify about 56 genes associated with the development of color blindness. Also, color blindness can be due to congenital pathologies: cone dystrophy, Leber's amaurosis, retinitis pigmentosa.
The acquired form of the disease is associated with damage to the occipital lobe of the brain that occurs during trauma, benign or malignant neoplasms, stroke, post-concussion syndrome, or retinal degeneration, exposure to ultraviolet radiation. Color blindness can be one of the symptoms of age-related macular degeneration, Parkinson's disease, cataracts, or diabetic retinopathy. A temporary loss of the ability to distinguish colors can be caused by poisoning or intoxication.
Symptoms of color blindness
The main symptom of color blindness is the inability to distinguish one color or another. Clinical forms of the disease: protanopia, tritanopia, deuteranopia and achromatopsia. Protanopia is a type of color blindness in which the perception of red hues is impaired. With tritanopia, patients do not distinguish the blue-violet part of the spectrum. In turn, deuteranopia is characterized by an inability to differentiate the color green. In the case of a complete lack of the ability to perceive color, we are talking about achromatopsia. Patients with this pathology see everything in black and white shades.
, the rarest and most unpleasant - complete color blindness - achromasia. Occurs with gross violations of the cone apparatus. At the same time, a person literally sees the world in black and white. In one of his books, the writer Oliver Sachs wrote about an entire island inhabited by such people.
But most often there is a defect in the perception of one of the primary colors, which indicates an abnormal trichromacy. Trichromats with proto-anomalous vision need more saturation of red shades in the image to differentiate yellow, deuteranomals - green. In turn, dichromats perceive the lost part of the color gamut with an admixture of preserved spectral shades (protanopes - with green and blue, deuteranopes - with red and blue, tritanopes - with green and red). Also distinguish between red-green blindness. In the development of this form of the disease, a key role is assigned to a mutation genetically linked to the sex. Pathological parts of the genome are localized on the X chromosome, so men are more likely to get sick.
To diagnose color blindness in ophthalmology, the Ishihara color test, the FALANT test, the study using an anomaloscope and Rabkin's polychromatic tables are used.
Ishihara color test includes a series of photographs. Each of the drawings depicts spots of various colors, which together create a certain pattern, part of which falls out of sight in patients, so they cannot name what exactly is drawn. The test also includes an image of figures - Arabic numerals, simple geometric symbols. The background of the figurine of this test differs little from the main background, therefore, patients with color blindness often see only the background, since it is difficult for them to differentiate minor changes in the color scale. Children who cannot distinguish numbers can be examined using special children's drawings (square, circle, car). The principle of diagnosing color blindness according to Rabkin's tables is similar.
Anomaloscopy and FALANT test are justified only in special cases (for example, when hiring with special requirements for color vision). With the help of anomaloscopy, it is possible not only to diagnose all types of color perception disorders, but also to study the influence of the brightness level, the duration of observation, color adaptation, air pressure and composition, noise, age, color discrimination training and the effect of drugs on the functioning of the receptor apparatus. The technique is used to establish the norms of perception and color discrimination in order to assess professional suitability in certain areas, as well as to control the treatment. The FALANT test is used in the United States to screen candidates for military service. To pass the test at a certain distance, it is necessary to determine the color emitted by the beacon. The lighthouse's glow is formed by merging three colors, which are somewhat muffled by a special filter. People with color blindness cannot name the color, but it has been proven that 30% of patients with mild disease are tested successfully.
Congenital color blindness can be diagnosed at later stages of development, since patients often call colors different from how they see them in connection with generally accepted concepts (grass - green, sky - blue, etc.). With a burdened family history, it is necessary to be examined by an ophthalmologist as soon as possible. Although the classic form of the disease is not prone to progression, with secondary color blindness caused by other diseases of the organ of vision (cataract, age-related macular degeneration, diabetic neuropathy), there is a tendency to the development of myopia and degenerative lesions of the retina, therefore, immediate treatment of the underlying pathology is required. Color blindness does not affect other characteristics of vision, therefore, a decrease in visual acuity or narrowing of the field of vision in a genetically determined form is not associated with this disease.
Additional studies are indicated in the case of acquired forms of the disease. The main pathology, the symptom of which is color blindness, can lead to a violation of other parameters of vision, as well as provoke the development of organic changes in the eyeball. Therefore, patients with the acquired form are recommended to carry out tonometry, ophthalmoscopy, perimetry, refractometry and biomicroscopy annually.
Color blindness treatment
Specific treatments for congenital color blindness have not been developed. Also, color blindness, which has arisen against the background of genetic pathologies (Leber's amaurosis, cone dystrophy), does not lend itself to therapy. Symptomatic therapy is based on the use of tinted glasses and contact lenses to help reduce the clinical manifestations of the disease. There are 5 types of contact lenses on the market in different colors to correct color blindness. The criterion for their effectiveness is 100% passing the Ishihara test. Previously, special software and cybernetic devices (ay-borg, cybernetic eyes, GNOME) were developed to help improve orientation in the color palette when working.
In some cases, the symptoms of acquired color vision disorders can be eliminated after the underlying disease has been cured (neurosurgical treatment of brain damage, surgery to eliminate cataracts, etc.).
Prediction and prevention of color blindness
The prognosis for color blindness for life and working capacity is favorable, but this pathology worsens the patient's quality of life. The diagnosis of color blindness limits the choice of profession in areas where color perception plays an important role (military personnel, commercial drivers, doctors). In some countries (Turkey, Romania), it is prohibited to issue a driver's license to patients with color blindness.