Advertising on the portal

Color vision deficiency is a disease. Color perception disorder

Drivers, namely: in addition to the updated form received by the driver applicant after passing the commission, the procedure itself and the list of doctors who give the go-ahead for the right to drive have changed somewhat vehicle. So, today, the conclusion of doctors such as ENT and neurologist will be mandatory only for truck drivers. A visit to an ophthalmologist remains unchanged, mandatory for everyone, regardless of the category received. Testing color perception and vision testing are an integral test for everyone who wants to drive a vehicle. If everything is clear with visual acuity, then let’s figure out what a color perception test is for drivers and whether it is possible to prepare for this test.

What is color perception?

Color perception is the ability of the human eye to distinguish a range of different colors. The cone cells in the retina are responsible for color perception. Normally, a person has three color-perceiving apparatus in the eye, in varying degrees excited under the influence of various wavelengths of radiation (red, green and blue). If the eye is not able to distinguish one color from another, that is, if the retina of the eye is not able to “catch” the difference in the wavelength of radiation, then a disorder occurs color vision. Like most diseases known to science, color vision disorder can be either acquired (observed in diseases optic nerve and retina), and congenital. The congenital inability to distinguish colors - color blindness - is a serious, insurmountable obstacle to obtaining a driver's license.

Diagnosis of color vision

So, how is color vision testing done for drivers? To determine color blindness among drivers, ophthalmologists have a special method in their arsenal that allows them to accurately identify this pathology. This method includes various polychromatic tables for checking color perception for drivers, namely: Ishihara, Fletcher-Gambling, Stilling, etc. However, the most common diagnostic method is Rabkin tests. Such tables are some kind of drawings assembled from dots and circles various diameters and flowers. A person who has deviations in color perception will simply not be able to distinguish and distinguish some colors from others, and therefore will not be able to see the hidden image.

A book for testing vision for a driver’s color vision consists of a set of Rabkin tables, differing in “purpose”: for example, the first 27 pictures are intended to identify color vision disorder, as well as its form. The remaining images in the book for testing drivers' color perception are needed to confirm and clarify the diagnosis.

Conditions for the color perception test

To obtain a reliable color perception test result for drivers, a number of conditions must be met:

  • The study is prohibited from being carried out under artificial lighting of the room. The normal state of health of the person being diagnosed guarantees an accurate result.
  • The subject should be “against the light”, that is, sit with his back to the window.
  • A book for testing drivers' color perception with tables should be kept at a distance of 1 meter from the patient's eyes, and the tables themselves should be positioned strictly vertically.
  • The time allotted for viewing one image is no more than 7 seconds.

Diagnostic results

Testing color perception for drivers can reveal a weakening of the subject’s perception of one of the colors (green or red), called anomalous trichromasia, which is divided into three types:

  • Complete loss of perception of red or green colors corresponds to type A.
  • Significant disturbance of color perception - type B.
  • A slight decrease in color perception by the patient is characterized by type C.

In addition to abnormal trichromasia, Rabkin’s polychromatic tables can detect more in a patient rare species deviations: dichromasia (failure to perceive one of three colors), as well as monochromasia (when the subject is unable to distinguish two colors at the same time).

Treatment of color vision disorders

Testing color perception for drivers can identify both congenital and acquired color blindness. If we're talking about O congenital pathology, then, unfortunately, science does not yet know treatment methods this violation functioning of the retina. The only way for colorblind people to see the world as it is, in its full glory, is only the development of Western scientists - special contact lenses. In addition, geneticists do not lose hope in developing a special technology that will allow the missing genes responsible for color perception to be introduced into retinal cells. Perhaps someday the efforts of scientists will bear fruit, and the term “color blindness” will remain a thing of the distant past.

As for the acquired inability to distinguish colors, when assessing the possibility of its cure, the causes of this deviation should be taken into account.

  • Color blindness, which appears as a result of age-related changes in the eye, cannot be cured. However, science knows of cases where replacing the lens returns normal color perception.
  • Color vision impairment caused by any chemical preparation, it is possible to completely cure - you just need to stop these drugs.
  • If color vision is impaired due to any injury, the outcome will depend on the degree of damage to the retina. In some cases it is possible full recovery perception to normal value.

Is it possible to “bypass” a color vision test?

Unfortunately, if a patient suffers from color vision impairment, it is almost impossible to successfully pass a color vision test. The option to memorize the tables is quite questionable, since the doctor can give the subject pictures selectively or in a different order. The only way out is to “agree” with the doctor. But in in this case you need to understand the seriousness of this act, because in the future the lives and health of not only yours, but also those of those around you may depend on this. If you find it difficult to even change the traffic light, then you need to think about whether it’s worth the risk.

Color perception- This is the eye's ability to distinguish colors. Color vision disorder- a fairly common disease. Named after the scientist, famous chemist John Dalton, who suffered from color blindness and was the first to accurately describe this condition (1798), called the disease color blindness.


Color vision disorders can be congenital or acquired. Congenital anomalies color perception are observed in approximately 8% of men and 0.5% of women and are caused by a defect in the X chromosome. Acquired color vision disorders found in diseases of the retina, optic nerve and central nervous system. They occur in one or both eyes, are expressed in a violation of the perception of all three colors, and are usually accompanied by a disorder of other visual functions and, unlike congenital ones, can undergo changes during the course of the disease and its treatment.

According to the three-component theory of color vision normal feeling color is called normal trichromasia- from the Greek word "chromos", color, and people with such vision - trichromats.

How the eye sees and why sometimes it does not distinguish colors

The reason for the lack of color perception is disturbances in the functioning of color-sensitive receptors (cones) located in the central zone of the retina. The human eye is capable of seeing colors when exposed to light with wavelengths from 396 to 760 nm. Color-sensing cones are located in the retina in groups - “bundles”. Humans have three types of cones, each of which contains a light-sensitive pigment that is responsible for the perception of one of the primary colors. One type of pigment reacts to a light spectrum with a wavelength of 552-557 nm (red), another to a spectrum with a wavelength of 530 nm (green), and a third to a blue spectrum with a wavelength of 426 nm. The eye analyzes the spectra of objects affecting it, separately evaluating rays with different wavelengths. The cerebral cortex synthesizes these excitations into a single resulting color of an object according to the laws of optical color mixing, and the analysis and synthesis of color perception occurs constantly and simultaneously.

Reduced color sensitivity

People whose cones contain all types of pigment have normal color vision. Some people experience a weakening of color sensitivity to one of the colors. This is due to a disruption in the production of one, two or all three light-sensitive pigments in the cones. Decreased perception of red color is called protanomaly, green - deuteranomaly and violet - tritanomaly. In fact, protanopes and deuteranopes do not distinguish between red and green colors, but instead see grayish-yellow shades of varying lightness; tritanopia does not occur as a congenital disorder.

Especially important color vision is present in many areas labor activity: in transport, in the chemical, dyeing, textile industries, in painting, decorative arts, medical specialties. Color affects the general physiological state of the body and performance, so it is important to appropriately design everything around a person in everyday life and in the workplace.

Color blindness (color blindness)- a hereditary, less commonly acquired feature of vision, expressed in the inability to distinguish one or more colors. This pathology is caused by damage to only one type of nerve cells in the retina - cones.

The famous chemist John Dalton, who first described color blindness in 1798, suffered from protanopia; In honor of him, this pathology was called “color blindness”

Causes of color blindness

Each of the three types of cones has its own type of color-sensitive pigment. In trichromats (people with normal color vision) cones contain required quantity all three pigments: red, green and blue. In color anomalies (people with impaired color perception), due to the absence or lack of pigment, the sensitivity of a certain group of cones is reduced: they cannot perceive the corresponding color.

There are congenital and acquired color blindness.

Congenital color blindness has a hereditary nature: it is associated with the X chromosome and is almost always transmitted from the mother - the carrier of the gene to the son. This pathology affects about 8% of men and only 0.5% of women.

Kinds:

1. Mild trichomasia. All three types of cones function, but with a weak ability to perceive color, a person cannot distinguish its shades.

2. Dichromasia- This is a type of color anomaly in which any one receiver does not work. Depending on what type of cones is not functioning, there are:

  • protanopia (a person does not perceive the color red);
  • deuteranopia (a person does not perceive green color);
  • tritanopia (a person cannot perceive Blue colour).

3. Monochromacy(complete color blindness) is a type of color abnormality in which all three groups of cones do not function. In this case, a person sees the image only with the help of sticks, and therefore the world is perceived by him as a black and white photograph. This pathology is extremely rare: only 0.1% of cases. It is usually accompanied by low visual acuity and photophobia. A monochromat is characterized by a sleepy or tired appearance, since his eyes are always squinted or half-closed.

As a rule, in the first two cases, patients do not complain about visual acuity. However, this disease limits the choice of profession: people with this pathology cannot work in transport. Upon issuance driver's license V mandatory color vision is checked using special tables.

Unfortunately, congenital color anomaly is incurable. But now special glasses with colored lenses are made for colorblind people. Such glasses function as light filters, allowing a person to distinguish between those colors and shades that are difficult for him to recognize.

Acquired color blindness may be caused age-related changes(including cataracts), injuries to the retina or optic nerve, various diseases, as well as taking certain medications.

Kinds:

Xanthopsia- a person sees surrounding objects in yellow.

This very common pathology can be caused by:

  • jaundice
  • drug poisoning

Erythropsia- a person sees surrounding objects in red. This pathology, which is usually caused by retinitis (inflammation of the retina), is quite rare.

Trianotopy- non-perception of blue color. Pathology is observed in some forms night blindness and is extremely rare.

As a rule, normal color perception with an acquired color anomaly is restored independently during the treatment of the diseases that caused this pathology, as well as when the medications that caused it are discontinued.

No wonder they say that every cloud has a silver lining. It is often much easier for a person with a congenital color anomaly than for people with normal vision to find an object that, due to its color, blends in with the surrounding background. For example, a color anomalist will easily notice a snake or other animal with a protective coloration, hiding among stones, grass or roots.

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

All colors are divided into two groups:

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

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

Depending From wavelength Three groups of colors can be distinguished:

A) long-wave (red, orange - “Every Hunter”)

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

C) short-wave (blue, blue, violet - “... where the pheasant sits”)

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

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

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

2) green cones – maximum spectral sensitivity at 530 nm

3) red cones – maximum spectral sensitivity at 560 nm

Color perception is the result of exposure to light on all three types of cones. Radiation of any wavelength excites all cones of the retina, but to varying degrees. When all three groups of cones are equally stimulated, a sensation of white color occurs.

There are congenital and acquired color vision disorders. They are always bilateral, are not accompanied by disturbances in other visual functions, and are detected during a special study.

Congenital color vision disorders may appear either

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

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

3) Black and white perception (monochromasia).

Congenital red color blindness – Colorblindness.

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

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

A) erythropsia – in red

B) xanthopsia – yellow

B) chloropsia – green

D) cyanopsia – blue.

Assessment of the color discrimination ability of the eye:

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

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

We kindly ask you not to send articles from the Internet - they can be found by search engines. Write your own, interesting and unique article. Take a photo and describe
laboratory work in physics or chemistry, send photos of your homemade product....

send articles to

[email protected]

Color vision impairment. Colorblindness To understand color vision disorder, you need to know the basic principle of color vision. In humans, color-sensitive receptors are located in the central part of the retina - nerve cells, which are called cones. Each of three types cones have their own type of color-sensitive pigment

protein origin

The most common type of color vision disorder is deuteranomaly, a green color vision disorder. With deuteranomaly, the green color is mixed with light orange and light pink. People with deuteranomal vision may not even be aware of their anomaly. With another type of color vision disorder, called “protanomaly” (weakness in the perception of red), the red color is mixed with light green and light brown. Color blindness in the blue-violet region of the spectrum is called tritanomaly; it is extremely rare and practical significance does not have. With tritanomaly, all colors of the spectrum appear as shades of red or green.

People who distinguish only two of the three primary colors have two-color vision, which is much more serious than the trichromasia anomaly discussed above. Two color vision there are three types:

Deuteranopia – green color blindness (long wavelengths)
Protanopia – red color blindness (medium waves)
Tritanopia is color blindness for blue light (short wavelengths).
Monochromasia is another type of color perception disorder.

Monochromats see everything in black and white and shades of gray. There are two types of monochromasia: rod monochromasy (retinal cell) and retinal cone monochromasy. The first type of color blindness is also called achromatopsia. People suffer from this type of disorder poor eyesight And high sensitivity to the light. Some may develop nystagmus (involuntary, rhythmic, biphasic movements of the eyeballs).

Theories about color anomaly

In 1801, Thomas Young proposed the theory of trichromacy. Later, Hermann von Helmholtz made changes to this theory, which is why the theory of trichomacy is called the Jung-Helmholtz theory. True, this is not the only theory about color anomaly.

Ewald Hering also proposed his vision of this phenomenon, who argued that color vision does not consist of three primary colors, but of several shades: light-dark, green-red and blue-yellow. Other scientists have tried to combine these two theories and achieved good results. Thanks to them, today we know much more about vision than about other senses. But there are still quite a lot of unsolved mysteries.