Light blindness. What color-blind people see: anomalous trichromasia. What are the types of color blindness

Color blindness is a permanent color blindness that does not change over time. Colorblind people are not able to distinguish colors, and therefore their quality of life is significantly reduced.

Color blindness can be congenital - genetically laid down, and acquired, associated with ophthalmic diseases and age-related changes.

Pathology was first described by the physician John Dalton in 1794 at the very end of the 18th century, who discovered it in himself. Later it was found that the causes of color blindness are underdevelopment of the retina or damage to the optic nerve.

The components of the retina are the rod and cone photoreceptors. The sticks are responsible for twilight vision and contain one pigment (rhodopsin). The function of cones is to distinguish the colors of the spectrum, they contain several pigments. If they are not enough or they are absent, color blindness develops.

The defect in the X chromosome is passed down the female line, but males are the most affected. Of all the colorblind people who got the disease from birth, only 4% are women.

Acquired color blindness is caused by ophthalmic diseases and injuries of the retina or by darkening of the lens.

Eye diseases that cause impaired color perception:

• macular degeneration;
• glaucoma;
• diabetic retinopathy;
• cataract.

These diseases interfere with the recognition of dark blue, green, and shades of gray.

If the diseases are caused by ophthalmological problems, then color perception can be restored - provided that treatment begins at the first symptoms.

Congenital color blindness is not treated.

color vision

Medical research has proven that people's ability to perceive the world in colors has developed gradually. Ancient people saw primary colors, and only then the ability to distinguish shades gradually appeared. How color vision developed can be seen from the progress visual arts- from bright pure colors to midtones.

The perception of colors in people is individual, there are racial and even national differences. It is traditionally believed that the Japanese and Chinese have the most colorful world (for example, a Chinese embroiderer distinguishes up to 200 shades of each color), the peoples of the North and Africans are deprived of color vision. In Japan, schools for children from the upper castes have long studied color vision, in connection with which they could distinguish up to 3000 colors and shades.

Color vision can be developed independently. Lay out samples of primary colors in front of you - preferably black and white. You may notice that the color on paper is different from the color on the fabric, the color of the metal, etc. Gradually improving, you can learn to distinguish the slightest nuances in the shades of primary colors. Then the ability is developed further - they move on to mixed colors - green, purple and the like.

To identify color blindness in the territory of the former CIS, Rabkin's tests are used - 96 tables, on which various colors - problematic for color blind people - are printed digital images for adults and animal figurines for small children. Since the color saturation of the images and the background is the same, color blind people cannot name what is drawn. This helps to identify those suffering from color blindness in advance and help them navigate in the surrounding space.

Types of color blindness

Currently, there are 4 types of violations color perception.

• Anomalous trichromacy.

Occurs most frequently.

In turn, it is classified as:

• tritanomaly is the most frequent pathology, at which blue and green merge;
• protanomaly - difficulties with only red, it is perceived as yellow or brown;
• deuteranomaly is a more serious violation, difficulties with color perception relate to green, yellow, orange and red.

However special problems pathology does not cause, the picture seen with tritanomaly and protanomaly from what everyone sees is not very distorted, the choice of professions is practically not limited.

• Dichromasia.

In this case, the violation of color perception is more pronounced.

Classification of pathology of this type:

As you can see, with dichromasia, one of the spectra is not perceived.

• Monochromatic.

Here, color perception is impaired at the level of signal transmission to the central nervous system, and therefore all images, like in an old TV, are black and white.

Anomaly classification:

• Monochromasia of blue cones has symptoms: myopia, loss of visual acuity, periodic trembling of the eyeballs, photophobia that develops in bright light. With monochromacy, color perception is not available.
• cone monochromacy: in low light, images from the retina are erased, that is, colors can only be seen under bright sun or electric light, the slightest semitones - the picture of what is seen is distorted;
• monochromatic rods - cones, which are responsible for the perception of colors and shades, are absent; information is perceived by the eyes, but does not reach the center of the brain responsible for processing;

• Achromasia.

The complete impossibility of color perception.

The colors don't differ at all. If achromasia is congenital, this is due to maculitis - lesions of the retina in the central part of the eye. Acquired ailment caused by trauma eyeball or its infection.

In this case, not only is it impossible to distinguish colors - vision drops so much that a person orients himself in space by squinting.

In addition to Rabkin's tests, the following are used to detect color blindness:

• a test for the distribution of objects by color - in most cases it is used for small patients;
• pseudo-isochromatic test - shades of colored dots are evaluated from different distances and under different illumination conditions.

With an acquired pathology, a complete ophthalmological examination is performed to identify the disease that caused a violation of color perception using:

• tables for checking visual acuity;
• lenses of various convexity and concavity;
• visual field assessments;
• inspection with a slit lamp and a mirror ophthalmoscope, etc.

Acquired color blindness is subject to correction.

How to treat color blindness?

Congenital color blindness, as already mentioned, cannot be cured.

To make life easier for color blind people, there are special techniques - patients are taught to focus on shades, they are prescribed special glasses with tinted glasses or narrowing the field of view, at least helping to create a difference between colors.

Each case is considered individually and unequivocally therapeutic regimen does not exist.

The treatment of an acquired anomaly depends on the problems that caused it. In the case of cataract or glaucoma, the patient is operated on, if the lens darkens, it is restored - if possible. Correction is helped special accessories- lenses or glasses.

Color blindness is not cured, but if the vision is normal, then it does not interfere with a full existence, limiting only the ability to engage in professional activity requiring the ability to distinguish colors.

Color-blind people are not taken as sailors and pilots; there are almost no artists and architects among them. "Almost" - because every rule has its exceptions. The famous Vrubel, Van Gogh and Savrasov suffered from color blindness.

Consisting in the inability of the eyes to color perception (one or more primary colors). In the center of the retina, in the so-called yellow spot, are special cages(cones) are photoreceptors. They provide human perception of color. There are 3 types of cones, each containing certain kind pigment - red, yellow or blue. These are the primary colors, and all other colors and shades are formed by mixing the primary colors.

The absence or deficiency of any pigment causes a violation of color perception. Most often, there is a lack of red pigment, less often - blue. If one pigment is missing, then such color blindness is called dichromacy. At the same time, a person can distinguish colors only by the "warm / cold" spectral characteristic: i.e. group "red, orange, yellow" from the group "blue, purple, green". And by the brightness of the color they try to distinguish a specific color. More often there is a lack of red pigment, less often - blue.

Causes of color blindness

Acquired color blindness develops due to past illness visual organs or central nervous system (with damage to the optic nerve), traumatic injury retina, chemical burn, or age-related changes.

Color blindness is a feature of vision, which is characterized by a violation of color perception. The disease was first described by the English chemist John Dalton in 1794. The scientist, as well as his brothers and sister, were protanotopes, that is, they did not distinguish red. The chemist learned about his color blindness only at the age of 26. Dalton described the disease in a book, after which the term color blindness appeared.

Men and women with this condition cannot distinguish between red, green, or Blue colour and their shades. This gives people a lot of discomfort and difficulties in life. Therefore, many are interested in whether it is possible to cure color blindness or avoid its development. Unfortunately, the disease inherited from parents is incurable.

What is colorblindness

Color blindness is a congenital (rarely acquired) disease that manifests itself in a wide variety of color perception defects. Most often, the pathology is transmitted to boys from mothers who are carriers of the disease. The risk of developing the disease in a child is especially high if close relatives of his mother also suffered from this disease.

As a rule, the gene for color blindness is recessive and is located on the X chromosome. This means that it leads to the development of the disease only in the absence of another, normal X chromosome. Women can carry the defective gene, pass it on to their children, and still have perfectly normal vision. Men have one X- and one Y-chromosome, which is why the gene that determines the development of color blindness immediately manifests itself in them.

Not so long ago, scientists studied the genotype of color blind people and found that mutations in 19 different chromosomes can become the cause of the disease. They also found about 60 different genes that can cause color blindness.

The reasons

As a rule, a person suffering from color blindness inherits a defective gene from his parents. Because of this, he develops a pathology of the cone apparatus of the retina, which is responsible for color perception. As you know, there are three types of cones in the retina, each of which has its own light-sensitive pigment. Different cones are responsible for receiving different wavelengths of light. Waves of length 570 nm are perceived as red, 544 nm - green, 443 nm - blue.

When one type of cone is affected, the perception of blue, green, or red is impaired. If several types are affected, a person does not distinguish between two primary colors at once or even the world in black and white. Such color perception anomalies are called achromasia and dichromasia.

It should be noted that color blindness is not only congenital, but can also develop secondarily. Some diseases of the retina, optic nerve or other parts of the visual analyzer lead to it.

Possible causes of color blindness:

• taking certain medications;
• age-related macular degeneration;
• diabetic retinopathy;
• retinitis pigmentosa;
• harmful effects of ultraviolet radiation on the retina;
• brain injury or neoplasm.

Symptoms

A characteristic symptom of color blindness is the inability to distinguish one or more colors, as well as their shades. Instead of green, blue or red, a color blind person sees gray. In addition, some patients may experience nystagmus (uncontrolled frequent oscillatory eye movements), decreased visual acuity, and some other unpleasant symptoms.

Types of color blindness

The disease is divided into the following types of color blindness:

• achromatopsia;
• monochromasia;
• dichromasia;
• abnormal trichromasia.

The first is typical black and white vision, with the second, a person distinguishes only one color (usually blue), with the third - two (blue and yellow).

However, it is anomalous trichromasia (protanomaly, deuteranomaly, or tritanomaly) that most often occurs in people. With this, the most mild degree color blindness, patients see all three primary colors, but perceive one of them distortedly.

Protanopia

Protanotopes completely lack the ability to distinguish red. This is due to the absence of visual pigment in one of the three types of cones. In the case of the preserved ability to distortly distinguish red colors we are talking about protanomaly.

Deuteranopia

A colorblind person with deuteranopia cannot differentiate between greens. Distorted Perception green is called deuteranomaly.

Tritanopia

Tritanopia is characterized by the inability to see blue. With tritanomaly, an inferior perception of the blue part of the color spectrum is revealed. Anomalies of visual perception are caused by a lack of visual pigments in various types cones.

Driver's license and other restrictions

Unfortunately, a color-blind person is not allowed to work as a driver. He cannot drive a road, rail or air vehicle. It should be noted that people with some color vision impairments may be able to obtain a driver's license (categories A and B), but they will state that they are not allowed to work for hire.

Colorblind can't go to work in strong structure. He cannot choose professions where color vision is necessary (chemist, doctors of certain specialties). As a rule, such people are not engaged in clothing modeling, interior design, landscape design etc.

Color blindness in men and women

From the above description of how color blindness is inherited, we can conclude that the disease is much more common in males.

A woman can get sick only if she receives two defective X chromosomes from her parents. Such inheritance of color blindness is rare.

According to statistics, about 6-8% of men and only 0.2-0.4% of women have color perception anomalies.

Color blindness in children

AT childhood color blindness is extremely difficult to diagnose. As a rule, it is rarely detected in babies. Usually the diagnosis is made already at an older age, during a preventive examination by an ophthalmologist.

To date, for the diagnosis of color blindness is most often used. Various numbers or symbols are drawn on them. A person with normal color vision will see all the signs without any problems, while a color-blind person will not be able to read some tables. To date, such tests are used very often, since they can be used to determine color blindness quickly and easily. They also allow you to find out what kind of color perception anomaly is present in the patient.

Diagnostics

To diagnose color blindness, the following methods are used:

• Rabkin's polychromatic tables;
• color test Ishihara;
• FALANT test;
• spectral methods - Nagel's anomaloscope, Rabkin's spectroanomaloscope, etc.

Treatment

Unfortunately, specific treatment color blindness has not yet been developed. Special lenses are used to correct abnormal trichromasia. It is possible to return normal color perception only in some cases, for example, with secondary color blindness caused by cataracts, traumatic brain injury or stroke.

Polarized lenses only allow certain light rays to pass through. They seem to cut off part of the light spectrum, so that a person gets the opportunity to see specific color. These lenses increase the contrast of vision, make colors more saturated and improve visual perception. Polarized lenses are used to make eyeglasses for colorblind people.

Forecast

With congenital color blindness, the prognosis for human life and health is favorable. However, people with impaired color perception experience some discomfort in everyday life.

Acquired color blindness may indicate serious illness visual analyzer or nervous system. In this case, the prognosis depends on the severity of the disease that caused the development of color blindness.

Is there a prevention

Unfortunately, specific prophylaxis disease has not yet been developed. In order to prevent acquired color blindness, you should regularly undergo preventive examinations see an ophthalmologist, treat cataracts, diabetic retinopathy and other diseases that can lead to impaired color perception in time.

Color blindness is a number of color perception anomalies in which a person cannot normally distinguish one or more colors. Violation of color perception can be congenital or acquired. In the second case, it may indicate serious pathology retina, optic nerve or other parts of the visual analyzer.

Unfortunately, in our time, color blindness is not amenable to treatment. Today there are special polarized lenses for colorblind people (abnormal trichromats). They are used to make glasses with which people can see the world in a brighter and more colorful way. Today, glasses can correct such types of color blindness as protanopia and deuteranopia.

Color blindness is a pathological condition associated with a violation of the perception of one of the primary colors. Scientists suggest that the disease is associated with genetic disorders. Gene anomalies or mutations lead to the development of color blindness, also called color blindness.

Daltonism is a disorder color vision, which characterizes itself by the fact that a person does not see (does not perceive) one of the primary colors. Color vision anomalies are classified by doctors as acquired (not due to genetic disorders) and congenital. Acquired color anomaly color blindness develops for several reasons, which we will discuss later.

For the first time, a doctor with the surname Dalton spoke about the fact that a person may have problems with the perception of colors. It happened in the middle of the XVIII century. The scientist discovered a pathology in himself, reaching the age of 26 years.

The doctor suggested that the cause of color blindness is genetic factor. Scientists often study their own family. This is what Dr. Dalton did. The medic found out that his sister and two of the three brothers had poor color vision. It turned out that almost all of the doctor's relatives suffered from color blindness.

So, who are color blind people and how do they see the world? These are color blind people. The wording means that for a reason visual anomaly the eye does not react to color. Instead of red or blue, the patient sees gray.

At the same time, patients with color blindness can be conditionally classified into several groups. Less common are color blind people who see the world in black and white.

Violation of color perception can be diagnosed in both a child and an adult. This pathology has no age restrictions.

Color blindness can be diagnosed in both a child and an adult.

Why does color blindness develop?

If we talk about acquired color blindness, then it occurs due to:

1. Traumatic eye injury (injury resulting in damage to the retina or optic nerve, may cause color deviations).
2. Trauma and diseases of the brain.
3. Brain tumors of a benign and malignant nature.

color anomaly may also occur as a result of genetic changes. This happens when the X chromosome is mutated.

Cause pathological condition may be taking certain medications. In this case, the violation is temporary and goes away on its own after stopping the medication.

Attention! The above factors have a direct impact on the development of the disease. But color blindness can also be diagnosed as a concomitant condition.

Anomalies of color vision are diagnosed:

• after a stroke;
• after suffering a coma;
• in diseases of the nervous system, color blindness is rarely diagnosed. But it can actively progress if a person has Parkinson's disease.

Reveal exact reason Genetics will help color blindness, since heredity plays an important role in the development of pathology. Color anomaly in 80% of cases is manifested in men and only in 20% of cases in women. The disease is associated with a mutation of the X chromosome. Women have 2 X chromosomes and men have one. Therefore, a woman is considered a carrier of the disease, a carrier of the gene.

Color anomaly in 80% of cases is manifested in men.

Color blindness and gene mutation often go hand in hand, this type of disease is congenital, not acquired.

Symptoms of the disease

Color blindness in a person can be manifested by the following symptoms:

1. Adults or children have difficulty recognizing colors.
2. When you look at the pictures, part of the picture disappears.
3. Color vision or perception is impaired, but when a violation occurs, a person correctly names the color.

Color blindness has different symptoms. The test helps to establish the presence of pathology. The essence of testing is that an ophthalmologist shows pictures to a patient who suffers from color blindness. different colors, tables. Color vision fails, and the patient does not answer the doctor's question. Parts of the picture fall out of the patient's horizon or the integrity of the pattern is violated. You can conduct such a test at home with the appropriate pictures, tables.

It is difficult to understand what it is to be color blind, because a person can recognize colors, but at the same time not react, not distinguish shades. In the process of diagnosing the disease, color blindness can be difficult, for this reason, ophthalmologists prescribe a number of diagnostic procedures to the patient.

To diagnose color blindness, special scales, tables and figures are used.

Classification of pathology

Color vision anomalies are various forms or types:

• Complete color blindness is the inability of a person to perceive colors, he sees the world in black and white.
• Dichromatism is a phenomenon that characterizes itself as a person's ability to distinguish only 2 primary colors.

The types of color blindness are different, the classification is carried out based on the patient's complaints and his ability to perceive colors.

Ophthalmologists distinguish the following types of color blindness:

• congenital - occurs due to gene mutations, more often diagnosed in early age(in children, adolescents);
• acquired - occurs as a result of injury, ophthalmic disease(clouding of the lens, myopia), can be diagnosed in both an adult and an elderly person, less often observed in children.

The degrees of color blindness depend on which pigment in the sector has failed and is not working properly. To deal with the degrees and types, you will have to delve into the study of the work of these pigments:

1. Blindness that occurs in the red part of the sector is called protanopia.
2. Blindness in the blue part of the spectrum is called tritanopia.
3. Blindness that occurs in the green part of the spectrum is called deuteronapia.

The type of color blindness depends on what shade a person does not perceive. Diagnosis and referral to an ophthalmologist will help classify the disease. The types of color blindness are different, but this does not mean that the classification changes the essence of the disease.

Diagnosis and referral to an ophthalmologist will help classify the disease.

Diagnosed congenital anomalies of color vision or acquired problems with color perception can be corrected!

Therapy and its methods

Let's see how to treat color blindness. Possible Methods treatments are divided into 2 groups:

1. Correction of the condition (takes place using specially selected lenses).
2. Treatment aimed at eliminating the root cause of color blindness (tumor, trauma, etc.)

How to cure color blindness resulting from gene mutation? It is impossible to get rid of the disease completely. The ophthalmologist selects corrective glasses or lenses with filters, they will have to be worn constantly.

Color blindness is treated by an ophthalmologist. If he comes to the conclusion that the disease arose as a result of damage to the eye or due to a tumor, then the doctor issues a referral to additional examination. After the diagnosis and identification of the cause of the anomaly of color vision, therapy is prescribed. There is no exact information on how effective treatment is in this case. It all depends on the cause of the pathology.

Corrective glasses are a chance for a color blind person to live in a colorful world

Disease prognosis

Can color blindness be cured? - the answer to this question interests many. If the condition has developed due to a genetic mutation, then the ophthalmologist will not be able to remove the gene for color blindness from the DNA chain.

Color vision anomalies are treated only if the cause of the disease is not related to genetics. Acquired color blindness can be cured.

Important: If the condition is corrected, wearing lenses and following the doctor's instructions, then success in the treatment of the disease can be achieved.

In Russia, a person diagnosed with color blindness has the right to drive a car and engage in various activities. Restrictions are imposed only on the performance of specific work, on certain types of military service.

Jul 12, 2017 Anastasia Tabalina

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

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

The reasons

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

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

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

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

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

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

Causes of acquired color vision disorders:

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

Symptoms

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

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

Diagnostics

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

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

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

Treatment

congenital color blindness this moment is not treated. Treatment of acquired color blindness is also not possible in all cases.

With acquired color blindness, color perception is corrected by surgical intervention. If color blindness was provoked by another disease, it is first of all necessary to treat it. So, for example, if color blindness appeared due to a cataract, it must be removed, as a result of which vision may improve. If the development of color blindness was due to the reception medical preparations, they need to be cancelled. This measure may affect the restoration of color vision.

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

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

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

Folk remedies

Medicine is not known folk remedies with which it would be possible to cure color blindness.

Complications

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

Prevention

There is no way to prevent color blindness.