The human eye is a rather complex mechanism. Its normal functioning depends on many factors, including the activity of the nervous system and the brain. As practice shows, a huge number of people are faced with violations in the work of the visual apparatus. And sometimes such problems do not cause any particular concern and are diagnosed by accident. Violation of color vision also belongs to such conditions, we will discuss congenital disorders of color vision in a little more detail.

Our eye is a special device that collects and refracts light rays emanating from various objects around us. The rays that have undergone refraction are focused on the eye retina, which is a complex of receptors responsible for receiving information. The retina contains rods and cones.

They transmit information from the retina to the nerves of vision, and then to the brain. Cones are responsible for color perception, there are three varieties of them - red, green and blue. If the functioning of some of them is disrupted, or if they are not functional at all, color perception defects occur.

Visual impairment in color is classified by specialists as color blindness. This condition is the inability to distinguish between the three primary colors (or one or two) and may be congenital or acquired.

Congenital disorders of color vision

It is believed that congenital color blindness is a genetic disease that is recessively associated with sex. This disorder occurs in eight percent of men and 0.4% of women. Despite the fact that color vision disorders are much less common among the fair sex, they are the carriers of the defective gene and pass it on by inheritance (usually to boys).

The ability to adequately perceive and distinguish between the three primary colors is called normal trichromacy. Accordingly, people with normal color perception are normal trichromats. With a congenital pathology of color perception in a person, the ability to distinguish those light radiations that an individual with normal color vision distinguishes is impaired.

Doctors distinguish three types of congenital color vision disorders:

Impaired perception of red, also called protan defect;
- green color perception defect - deuterium defect;
- impaired perception of blue color - tritan defect.

If the perception of only one color is disturbed (in most cases, there is a reduced discrimination of green, a little less often - red), the whole color perception changes in a person, because the visual apparatus is not capable of normal mixing of colors.

Depending on the severity, color perception disorders are divided into three states:

abnormal trichromacy;
- dichromacy;
- monochromatic.

In the event that a person does not distinguish a particular color very well (but, nevertheless, perceives it), such a condition is classified as anomalous trichromasia.
Doctors call complete non-perception of some color dichromacy (in this case, a person distinguishes only two components). And the inability to distinguish all three colors is called monochromacy.

It should be noted that the latter violation is extremely rare. In most cases, color blindness is accompanied by the absence or some damage to only one of the three photoreceptor pigments, respectively, most often doctors are faced with the problem of dichromasia.

Dichromats have a peculiar color perception. They often find out about their existing deficiency by chance, for example, during special examinations and tests, or when they get into difficult life situations.

How to identify congenital color vision disorders?

To determine such conditions, doctors use special polychromatic tables (they contain many colors), in some cases spectral anamaloscopes are used.

The patient is shown a series of tables, his answers are recorded and the number of correct ones is analyzed, thus determining the type of color blindness and its severity.

Can congenital color vision disorders be cured?

Unfortunately, congenital color blindness is completely untreatable. However, many people live quite successfully with this disorder. They should only remember their peculiarities and adjust the information they receive taking it into account.

It is worth noting that a violation of color perception is a one hundred percent contraindication for activities in certain types of industry. People with such a disease cannot work as drivers (on any type of transport), serve in some troops. Full color vision is extremely important for servicing various equipment, etc.

What is the difference between an acquired color vision disorder and a congenital one?

Acquired color blindness can develop with a variety of disorders, this condition is explained by pathological processes in the retina or optic nerve. Sometimes an acquired disease develops when the overlying parts of the visual analyzer of the central nervous system are affected. Such conditions can occur against the background of somatic diseases of the body.

Acquired color blindness can be provoked by toxic effects, vascular disorders, inflammatory and demyelinating processes, etc.

Unlike congenital disorders, many of these pathologies are successfully treatable; accordingly, acquired color blindness is often reversible. Another difference from the congenital form of the disease is the occurrence of initial color vision defects in only one eye. In the absence of adequate correction, the disorder progresses and often leads to a decrease in visual acuity and visual field disturbances.

Congenital color blindness is actually a rather rare pathology, which in most cases does not affect the quality of life in any way and is detected quite by accident.

Color vision is a unique natural gift. Few creatures on Earth are able to distinguish not only the contours of objects, but also many other visual characteristics: color and its shades, brightness and contrast. However, despite the apparent simplicity of the process and its routine, the true mechanism of color perception in humans is extremely complex and not known for certain.

There are several types of photoreceptors on the retina: sticks And cones. The sensitivity spectrum of the former allows for object vision in low light conditions, and the latter for color vision.

At present, the three-component theory of Lomonosov-Jung-Helmholtz, supplemented by the opposing concept of Hering, has been adopted as the basis for color vision. According to the first, on the human retina There are three types of photoreceptors(cones): "red", "green" and "blue". They are mosaically arranged in central region eye fundus.

Each species contains a pigment (visual purple) that differs from the others in chemical composition and the ability to absorb light waves of various wavelengths. The colors of the cones, by which they are called, are arbitrary and reflect the light sensitivity maxima (red - 580 microns, green - 535 microns, blue - 440 microns), and not their true color.

As can be seen from the graph, the sensitivity spectra overlap. Thus, one light wave can to some extent excite several types of photoreceptors. Getting on them, the light generates chemical reactions in the cones, leading to the “burning out” of the pigment, which is restored after a short period of time. This explains the blindness when we look at something bright, such as a light bulb or the sun. The reactions that arose as a result of hitting a light wave lead to the formation of a nerve impulse that travels along a complex neural network to the visual centers of the brain.

It is believed that it is at the stage of signal passage that the mechanisms described in Goering's opposite concept are activated. It is likely that nerve fibers from each photoreceptor form so-called opponent channels ("red-green", "blue-yellow" and "black-white"). This explains the ability to perceive not only the brightness of colors, but also their contrast. As evidence, Hering used the fact that it was impossible to imagine such colors as red-green or yellow-blue, and also that when these, in his opinion, "primary colors" were mixed, they disappeared, giving white.

Taking into account the foregoing, it is easy to imagine what will happen if the function of one or more color receivers decreases or is completely absent: the perception of the color gamut will change significantly compared to the norm, and the degree of change in each case will depend on the degree of dysfunction, individual for each color anomaly.

Symptoms and classification

The state of the color-perceiving system of the body, in which all colors and shades are fully perceived, is called normal trichromasia(from Greek chroma - color). In this case, all three elements of the cone system ("red", "green" and "blue") work in full mode.

At anomalous trichromats violation of color perception is expressed in the indistinguishability of any shades of a particular color. The severity of changes directly depends on the severity of the pathology. People with mild color anomalies often do not even know about their peculiarity and learn about it only after passing medical examinations, which, according to the results of examinations, can significantly limit their career guidance and further work.

Anomalous trichromasia is subdivided into protanomaly- impaired perception of red color, deuteranomaly- violation of the perception of green and tritanomaly- violation of the perception of blue color (classification according to Chris-Nagel-Rabkin).

Protanomaly and deuteranomaly can be of different severity: A, B and C (in descending order).

At dichromasia a person lacks one type of cone, and he perceives only two primary colors. An anomaly due to which red is not perceived is called protanopia, green is deuteranopia, blue is tritanopia.

However, despite the apparent simplicity, to understand How do people with altered color vision actually see?, is extremely difficult. The presence of one non-functioning receiver (for example, red) does not mean that a person sees all colors except this one. This gamut is individual in each case, although it has a certain similarity with that of other people with a color vision defect. In some cases, there may be a combined decrease in the functioning of cones of various types, which introduces "disturbance" into the manifestation of the perceived spectrum. Cases of monocular protanomalies can be found in the literature.

Table 1: Perception of colors by individuals with normal trichromasia, protanopia and deuteranopia.

The table below reflects the main differences in the perception of colors by normal trichromats and individuals with dichromasia. Protanomalies and deuteranomals have similar impairments in the perception of certain colors depending on the severity of the condition. The table shows that the definition of protanopia as blindness to red, and deuteranopia - to green is not entirely correct. Research scientists have found that protanopes and deuteranopes do not distinguish between red or green colors. Instead, they see shades of greyish-yellow of varying lightness.

The most severe degree of color vision impairment is monochromacy- complete color blindness. Allocate rod monochromasia (achromatopsia), when cones are completely absent on the retina, and with a complete disruption of the functioning of two of the three types of cones - cone monochromasia.

In case of rod monochromacy When there are no cones on the retina, all colors are perceived as shades of gray. Such patients also usually have low vision, photophobia, and nystagmus. At cone monochromacy different colors are perceived as one color tone, but vision is usually relatively good.

To designate color perception defects in the Russian Federation, two classifications are simultaneously used, which confuses some ophthalmologists.

Classification of congenital disorders of color perception according to Chris-Nagel-Rabkin

Classification of congenital disorders of color perception according to Nyberg-Rautian-Yustova

Main difference between them lies only in the verification of partial violations of color vision. According to the Nyberg-Rautian-Yustova classification, the weakening of cone function is called color weakness, and depending on the type of photoreceptors involved, it can be divided into proto-, deuto-, tritodeficiency, and according to the degree of impairment - I, II and III degree (ascending). There are no differences in the upper part of the schematically reflected classifications.

According to the authors of the latter classification, a change in color sensitivity curves is possible both along the abscissa (change in the range of spectral sensitivity) and along the ordinate (change in the sensitivity of cones). In the first case, this indicates an anomalous color perception (anomalous trichromasia), and in the second, a change in color strength (color weakness). Persons with color weakness have reduced color sensitivity of one of the three colors, and brighter shades of this color are needed for proper discrimination. The required brightness depends on the degree of color weakness. Anomalous trichromasia and color weakness, according to the authors, exist independently of each other, although they often occur together.

Also, color anomalies can be sort by color spectrum, the perception of which is impaired: red-green (protano- and deuteron disorders) and blue-yellow (triton disorders). Origin all violations of color perception can be congenital and acquired.

color blindness

The term "color blindness", which has become widespread in our lives, is more slang, since in different countries can indicate various color vision disorders. We owe its appearance to the English chemist John Dalton, who first described this condition in 1798, based on his feelings. He noticed that the flower, which in the daytime, in the light of the sun, was sky blue (more precisely, the color that he considered sky blue), in the light of a candle looked dark red. He turned to those around him, but no one saw such a strange transformation, with the exception of his own brother. Thus, Dalton guessed that something was wrong with his vision and that the problem was inherited. In 1995, studies were carried out on the preserved eye of John Dalton, during which it turned out that he suffered from deuteranomaly. It usually combines "red-green" color perception disorders. Thus, despite the fact that the term color blindness is widely used in everyday life, it is incorrect to use it for any violation of color vision.

This article does not deal in detail with other manifestations of the organ of vision. We only note that most often patients with congenital forms of color perception disorders do not have any special, specific disorders for them. Their vision is no different from that of an ordinary person. However, patients with acquired forms of pathology may experience various problems, depending on the cause that caused the condition (decrease in correctable visual acuity, visual field defects, etc.).

Causes

Most often in practice congenital disorders occur color perception. The most common of these are "red-green" defects: protano- and deuteranomaly, less often protano- and deuteranopia. Mutations in the X chromosome (linked to sex) are considered to be the cause of the development of these conditions, as a result of which the defect is much more common in males (about 8% of all men) than females (only 0.6%). The occurrence of different types of "red-green" color vision defects is also different, which is shown in the table. About 75% of all violations of color perception are deuteron violations.

In practice, congenital tritan defect is extremely rare: tritanopia - in less than 1%, tritanomaly - in 0.0001%. The frequency of occurrence in both sexes is the same. In such people, a mutation is determined in a gene located on the 7th chromosome.

In fact, the frequency of occurrence of color perception disorders among the population can vary significantly depending on ethnicity, territorial affiliation. So, on the Pacific island of Pingelap, which is part of Micronesia, the prevalence of achromatopsia among the local population is 10%, and 30% are its hidden carriers in the genotype. The occurrence of a “red-green” color defect among one ethno-confessional group of Arabs (Druze) is 10%, while among the indigenous inhabitants of the island of Fiji it is only 0.8%.

Some conditions (inherited or congenital) can also cause color vision problems. Clinical manifestations can be detected both immediately after birth and throughout life. These include: cone and rod-cone dystrophy, achromatopsia, blue cone monochromasia, Leber's congenital amaurosis, retinitis pigmentosa. In these cases, there is often a progressive deterioration in color vision as the disease progresses.

Diabetes, glaucoma, macular degeneration, Alzheimer's disease, Parkinson's disease, multiple sclerosis, leukemia, sickle cell anemia, brain injury, damage to the retina by ultraviolet light, vitamin A deficiency, various toxic agents (alcohol, nicotine) can lead to the development of acquired forms of color vision impairment. medicines(plaquenil, ethambutol, chloroquine, isoniazid).

Diagnostics

At present, color vision assessment is given undeservedly little attention. Most often, in our country, verification is limited to demonstrating the most common tables of Rabkin or Yustova and an expert assessment of suitability for a particular activity.

Indeed, a violation of color perception often has no specificity for any disease. However, it can indicate the presence of those at a stage when there are no other signs. At the same time, the ease of use of tests makes it easy to apply them in everyday practice.

The simplest can be considered color comparative tests. For their implementation, only uniform lighting is necessary. The most accessible: alternate demonstration of the source of red color to the right and left eyes. At the beginning of the inflammatory process in the optic nerve, the subject will note a decrease in the saturation of tone and brightness on the affected side. Also, the Kolling table can be used to diagnose pre- and retrochiasmal lesions. In pathology, patients will note discoloration of the images on one side or another, depending on the localization of the focus.

Other methods that help in diagnosing a color vision disorder are pseudo-isochromatic tables and color ranking tests. The essence of their construction is similar, and is based on the concept of a color triangle.

The color triangle on the plane reflects the colors that the human eye can distinguish.

The most saturated (spectral) are located on the periphery, while the degree of saturation decreases towards the center, approaching white. The white color in the center of the triangle is the result of a balanced excitation of all types of cones.

Depending on which type of cone is underfunctioning, a person cannot distinguish certain colors. They are located on the so-called lines of non-distinction, converging to the corresponding corner of the triangle.

To create pseudo-isochromatic tables, the colors of the optotypes and the background (“masking”) surrounding them were obtained from different segments of the same line of indistinguishability. Depending on the type of color anomaly, the subject is not able to distinguish between certain optotypes on the displayed cards. This allows you to identify not only the type, but also in some cases the severity of the existing violation.

Developed many options for such tables: Rabkina, Yustova, Velhagen-Broschmann-Kuchenbecker, Ishihara. Due to the fact that their parameters are static, these tests are better suited for diagnosing congenital anomalies of color perception than acquired ones, since the latter are characterized by variability.

Color ranking tests are a set of chips whose colors correspond to the colors in the color triangle around the white center. A normal trichromat is able to arrange them in the required order, while a patient with impaired color perception is only in accordance with the lines of indistinguishability.

Currently used: Farnsworth 15-chip panel test (saturated colors) and its modification Lanthony with desaturated colors, Roth 28-shade test, as well as Farnsworth-Munsell 100-shade test for more detailed diagnostics. These methods are more suitable for identifying acquired color perception disorders, as they help to assess them more accurately, especially in dynamics.

A certain disadvantage in the use of pseudo-isochromatic tables and color ranking tests is the strict requirements for illumination, the quality of the displayed samples, storage conditions (it is necessary to avoid burnout, etc.).

Another method that helps in the quantitative diagnosis of color perception disorders is the anomaloscope. The principle of its operation is based on the formulation of the Rayleigh equation (for the red-green spectrum) and Moreland (for blue): the selection of color pairs, which gives a color indistinguishable from a monochromatic (from one wavelength color) sample. Mixing green (549 nm) and red (666 nm) gives the equivalent yellow (589 nm), with the differences balanced by the change in brightness of the yellow (Rayleigh's equation).

A Pitt chart is used to record the results. The colors obtained by mixing red and green are placed along the abscissa depending on the amount of each of them in the mixture (0 - pure green, 73 - pure red), and the brightness - along the ordinate. Normally, the resulting color is equal to the control is 40/15, respectively.

In case of violations of the "green" color receiver, to obtain such equality, more green is needed, and in case of a "red" defect, add red and lower the brightness of yellow. In cerebral achromatopsia virtually any ratio of red and green can be equated with yellow.

The disadvantage of the technique may be the need for special expensive equipment.

Treatment

Currently, there is no effective treatment for color vision disorders. However, spectacle lens manufacturers are constantly trying to develop special filters that will change the spectral sensitivity of the eye. In fact, full-fledged scientific research in this direction has not been conducted, so it is not possible to reliably judge their effectiveness. Judging by the complexity and versatility of the color discrimination process, their usefulness seems doubtful. Acquired color vision disorders are able to regress when the cause that caused them is eliminated, but also do not have a specific treatment.

Due to the impossibility of treating these conditions, the main issue remains the expediency and degree of restriction of persons with color anomalies, especially those with congenital changes in color perception. In different countries of the world, this issue is approached in different ways. Sometimes people with similar color vision problems may have radically different opportunities for choosing a profession, participating in traffic, etc. In my opinion, given the wide prevalence of anomalies, it makes sense not to follow the path of limiting such people in their activities, but to try to level the influence of the color factor on their work and life.

A new power structure has appeared in Russia - the National Guard.

This was announced on April 5, 2016 by the President Russian Federation Vladimir Putin at a meeting with Russian Interior Minister General of Police Vladimir Kolokoltsev, Director of the Russian Federal Drug Control Service Viktor Ivanov, Commander-in-Chief of the Internal Troops of the Russian Interior Ministry General of the Army Viktor Zolotov and Deputy Director of the Federal Migration Service Ekaterina Yegorova. The President stressed that the new structure will be created on the basis of the internal troops of the Ministry of Internal Affairs. According to Vladimir Putin, the tasks of the National Guard will include the fight against terrorism, organized crime, as well as the performance of functions that are currently assigned to the OMON and OMSN (SOBR) units. Another decision of the president, announced at this meeting, is to reassign the Federal Migration Service and the Federal Drug Control Service to the Ministry of Internal Affairs of the Russian Federation. In the near future, the creation of the National Guard will be fixed not only in the corresponding decree of the President of the Russian Federation, but also in federal law.

The National Guard will become a power structure separate from the Ministry of Internal Affairs of the Russian Federation. Presumably, this may be due to budgetary difficulties and the need to change the structure of the Ministry of Internal Affairs of the Russian Federation, which includes the Federal Migration Service and the Federal Drug Control Service. In this case, the number of the Ministry of Internal Affairs of the Russian Federation will remain practically unchanged, but the military personnel of the internal troops will go to the National Guard of the Russian Federation.

It should be noted that talks about the creation of the National Guard in the Russian Federation have been going on for a long time. Thus, in 2012, a number of mass media reported on the possible formation of the National Guard in the country, directly subordinate to the president and focused on ensuring the country's security and protecting the constitutional order. Then it was assumed that the Internal Troops of the Ministry of Internal Affairs of the Russian Federation would become the base for the National Guard, but it would also include some units of the Airborne Forces and the recently created military police Ministry of Defense of the Russian Federation. In 2012, it was assumed that the number of personnel of the National Guard would be 350-400 thousand people. Preparations for the creation of the National Guard were explained by the need for a power structure capable of quickly responding to new threats to the security of the Russian state, which are growing in an increasingly complex world situation.

In 2012, Army General Nikolai Rogozhkin, who at that time held the post of Commander-in-Chief of the Internal Troops of the Ministry of Internal Affairs of the Russian Federation, was expected to head the new power structure (Nikolai Evgenievich Rogozhkin spent almost 10 years in this position - from August 2004 to May 2014). However, in 2014, Nikolai Rogozhkin was fired from military service and was appointed Plenipotentiary Representative of the President of the Russian Federation in the Siberian federal district. Another possible candidate for the post of Commander-in-Chief of the National Guard was named back in 2012, Colonel-General Viktor Zolotov, a representative of the special services, long time responsible for the security of the highest officials of the Russian (and before - the Soviet) state. police as part of the criminal police, public security police, migration police and special departments; federal investigation service; municipal police transferred to the maintenance of the regions; federal guard, into which the Internal Troops of the Ministry of Internal Affairs of the Russian Federation will be transformed. At the same time, even in 2004, it was not ruled out that the federal guard from the Ministry of Internal Affairs of the Russian Federation could become directly subordinate to the President of the Russian Federation. The functions of the federal guard were going to include the protection of public order, ensuring public safety in emergency situations, and the protection of especially important objects. state importance, the fight against terrorism and organized crime.

Naturally, the idea of ​​forming the National Guard as separate troops, directly subordinate to the president and focused on solving operational tasks to ensure national security and protect the country's constitutional order, then caused numerous criticism from the Russian opposition, especially the liberal ones. The authorities were accused almost of creating "oprichniki" who were not controlled by the federal ministry responsible for law and order. At the same time, the opposition ignored the fact that such structures exist in many countries of the world, including their beloved United States of America (National Guard), as well as such European countries as France (National Gendarmerie) and Spain (Civil Guard). However, neither in 2004 nor in 2012. there were no measures to create the National Guard, so it seemed to many that this idea would remain at the level of long-term projects and was unlikely to be implemented in the foreseeable future. Army General Nikolai Rogozhkin, who commanded the Internal Troops, said that the Internal Troops would retain their status and former appearance until 2015, the Security Council of the Russian Federation decided so. As you can see, he was right - in 2016 the situation changed. From April 5, 2016, the National Guard in the Russian Federation can count the beginning of its existence.

Some analysts talk about the creation of the National Guard as a separate power structure, isolated from the Ministry of Internal Affairs of the Russian Federation, as a strengthening of the personal political positions of specific individuals, in particular, the commander-in-chief of the Internal Troops of the Ministry of Internal Affairs, General Viktor Zolotov. Nikolai Mironov, head of the Center for Economic and Political Reforms, voiced this version to RIA Novosti journalists. The new independent power structure, which will work in close contact with the Ministry of Internal Affairs, but at the same time represent well-armed, trained and highly mobile troops, is an additional power resource for the authorities. Naturally, the positions of the head of this power structure and his influence in the higher echelons Russian authorities increase sharply. On the evening of April 5, it became known that President of the Russian Federation Vladimir Putin signed a decree appointing Army General Viktor Zolotov as Director of the Federal Service of the National Guard Troops of the Russian Federation.

At the same time, the Ministry of Internal Affairs of the Russian Federation also received "compensation" - the Federal Migration Service and the Federal Drug Control Service were included in the ministry. In fact, the isolation of these structures from the Ministry of Internal Affairs was at one time a rather controversial idea. After all, the creation of independent migration and anti-drug structures significantly complicated the functioning of the Ministry of Internal Affairs and law enforcement in general, since there was a need for interdepartmental coordination of activities. In addition, the ministry and federal services in some matters they actually performed duplicating functions, and the employees of the Federal Migration Service and the Federal Drug Control Service still did not have the full powers of police officers and were not perceived by society as such. An even more important problem was the lack of FSKN staff and the separation of the department's functions from the fight against ordinary crimes closely related to the distribution or use of drugs. This created additional difficulties in the fight against crime in the territory of the Russian Federation. So the decision to transfer the Federal Migration Service and the Federal Drug Control Service to the Ministry of Internal Affairs can be considered quite justified, especially in difficult economic conditions, when it really would not be superfluous to reduce budget expenditures related to the financing of independent law enforcement agencies.

The importance of strengthening the troops that ensure national security and the protection of the constitutional order of the country is beyond doubt. Especially in such a difficult situation that we are witnessing in the world today, including in the immediate vicinity of the Russian borders. The fight against terrorism and extremism, against the threat of new "hybrid wars", against "color revolutions" and riots implies the creation of a modern and mobile power structure capable of effectively responding to all the challenges and risks of our time. Therefore, it is difficult to dispute the relevance of the creation of the National Guard, especially since this issue has been worked out many times Russian leadership actually highest level.

However, some questions are raised by the "symbolic" side of the formation of a new power structure. As you know, the first National Guard was created in Paris in 1789 in accordance with the decision of the Constituent Assembly of France - to maintain order in the city during the French Revolution and subsequent events. Later, the armed forces of the Paris Commune were called the National Guard. In 1872 the French National Guard was dissolved. Then this name began to be used by paramilitary groups that performed the functions of protecting internal order and national security in a number of countries around the world. It is noteworthy that the very name "National Guard" is used mainly in those countries with which Soviet Union, and then the Russian Federation had a very difficult relationship.

The most famous, of course, is the National Guard of the United States of America, which is an organized reserve of the US Armed Forces and is used to suppress riots and popular uprisings, eliminate the consequences of emergencies, fight crime and illegal armed groups. Its national guards in the twentieth century and currently has a number of countries of Central and South America- they created these structures on the model of the US National Guard. In the 1990s formations of the national guard existed in Chechnya under the rule of Dzhokhar Dudayev, in Georgia. The National Guard was created in the post-Soviet republics - Azerbaijan, Kazakhstan, Ukraine, where it actually replaced the former Internal Troops, taking most their functions. At the same time, in Ukraine the National Guard existed twice - from 1991 to 2000. and, again, since 2014, at the base of the internal troops. Until now, the National Guard of Ukraine is not a separate power structure, but is part of the Ministry of Internal Affairs of the country.

After the events in Ukraine in 2013-2014. and the beginning of the armed conflict in the Donbass, the very word “National Guard” acquired a negative connotation for many Russian citizens. The Ukrainian "National Guard" was presented in the media exclusively as a punitive organization engaged in suppressing the actions of the inhabitants of Donbass and terrorizing the population of Russian-speaking territories. The so-called “volunteer battalions of the National Guard”, staffed to a large extent by activists of Ukrainian nationalist organizations, received notoriety. It was with the activities of these battalions that many war crimes committed on the territory of Donbass were connected. In one of these battalions, the notorious Nadezhda Savchenko, recently convicted by a Russian court, served as a spotter.

Of course, the phrase "National Guard" itself cannot carry a negative connotation - the guards are the best, selected units, the National Guard are the best, selected troops of the country used to protect national security. However, the war in Donbass has made the phrase "National Guard" a household word for many. Now it cuts the ear, if not to the majority, then to a significant part of Russians for sure. And first of all, this concerns the same residents of Crimea, which has recently reunited with Russia. In general, with the renaming of the Internal Troops into the National Guard, the same story may arise as with the renaming of the militia into the police. In everyday life, after all, many Russians still call the police militia, police officers - militiamen, exactly the same situation can be if, instead of the well-known "VV-shnikov", "national guards" appear. In any case, it will take quite a long time for the Russians to adapt to the new name.

Color vision disorders are divided into congenital and acquired. Functional defects of the cone system may be due to hereditary factors and pathological processes at various levels of the visual system.

Congenital disorders of color vision are genetically determined and are recessively associated with sex. They occur in 8% of men and 0.4% of women. Although color vision disorders are observed much less frequently in women, they are carriers of the pathological gene and its transmitters.

The ability to correctly distinguish primary colors is called normal trichromacy, people with normal color perception - normal trichromats. Congenital pathology of color perception is expressed in a violation of the ability to distinguish light radiation, distinguishable by a person with normal color vision. There are three types of congenital color vision defects: a defect in the perception of red (protan defect), green (deuter defect) and blue (tritan defect).

If the perception of only one color is disturbed (more often there is a reduced discrimination of green, less often - red), the entire color perception as a whole changes, since there is no normal mixing of colors. According to the degree of severity, changes in color perception are divided into anomalous trichromasia, dichromasia and monochromasia. If the perception of any color is reduced, then this condition is called abnormal trichromasia.

Complete blindness to any color is called dichromacy(only two components differ), and blindness to all colors (black and white perception) - monochromatic.

Damage to all pigments at the same time is extremely rare. Almost all disorders are characterized by the absence or damage of one of the three photoreceptor pigments and thus are the cause of dichromasia. Dichromats have a peculiar color vision and often find out about their deficiency by accident (during special examinations or in some difficult situations). life situations). Color vision disorders are called color blindness after the scientist Dalton, who first described dichromasia.

Acquired color vision disorder can manifest itself in a violation of the perception of all three colors. In clinical practice, the classification of acquired color vision disorders is recognized, in which they are divided into three types depending on the mechanisms of occurrence: absorption, alteration and reduction. Acquired disorders of color perception are caused by pathological processes in the retina (due to genetically determined and acquired diseases of the retina), the optic nerve, overlying parts of the visual analyzer in the central nervous system and can occur with somatic diseases of the body. The factors that cause them are varied: toxic effects, vascular disorders, inflammatory, demyelinating processes, etc.

Some of the earliest and most reversible drug toxic effects (after chloroquine or vitamin A deficiency) are monitored in repeated color vision tests; documenting the progress and regression of changes. When taking chloroquine, visible objects turn green, and with high bilirubinemia, which is accompanied by the appearance of bilirubin in the vitreous, objects turn yellow.

Acquired color vision disorders are always secondary, so they are determined randomly. Depending on the sensitivity of the research method, these changes can be diagnosed already with an initial decrease in visual acuity, as well as with early changes in the fundus. If at the beginning of the disease the sensitivity to red, green or blue color is disturbed, then with the development pathological process sensitivity to all three primary colors is reduced.

Unlike congenital, acquired color vision defects, at least at the onset of the disease, appear in one eye. Color vision disorders in them become more pronounced with time and may be associated with a violation of the transparency of optical media, but are more often related to the pathology of the macular area of ​​the retina. As they progress, they are joined by a decrease in visual acuity, visual field disturbances, etc.

To study color vision, polychromatic (multi-color) tables and occasionally spectral anomaloscopes are used. There are more than a dozen tests to diagnose color vision defects. In clinical practice, the most common are pseudoisochromatic tables, first proposed by Stilling in 1876. The tables of Felhagen, Rabkin, Fletcher, and others are currently used more often than others. They are used to identify both congenital and acquired disorders. In addition to them, Ishihara, Stilling or Hardy-Ritler tables are used. The most widespread and recognized in the diagnosis of acquired color vision disorders are panel tests created on the basis of the standard Munsell color atlas. Abroad, 15-, 85- and 100-shade Farnsworth tests of various colors are widely used.

The patient is shown a series of tables, the number of correct answers in different color zones is counted, and thus the type and severity of the deficiency (insufficiency) of color perception is determined.

Rabkin's polychromatic tables are widely used in domestic ophthalmology. They consist of multi-colored circles of the same brightness. Some of them, painted in one color, form against the background of the rest, painted in a different color, some number or figure. These signs that stand out in color are easily distinguishable with normal color perception, but merge with the surrounding background with inferior color perception. In addition, there are hidden signs in the table that differ from the background not in color, but in the brightness of the circles that make them up. These hidden signs are distinguished only by persons with impaired color perception.

The study is carried out in daylight. The patient sits with his back to the light. Tables are recommended to be presented at arm's length (66-100 cm) with an exposure of 1-2 s, but not more than 10 s. If in order to detect congenital defects in color perception, especially during mass professional selections, in order to save time, it is permissible to test two eyes at the same time, then if acquired changes in color perception are suspected, testing should be carried out only monocularly. The first two tables are control, they are read by persons with normal and impaired color perception. If the patient does not read them, it is a simulation of color blindness.

If the patient does not distinguish between obvious signs, but confidently names hidden signs, he has a congenital color perception disorder. In the study of color perception, dissimulation is often encountered. To this end, tables are memorized and recognized by appearance. Therefore, at the slightest uncertainty of the patient, one should diversify the ways of presenting the tables or use other polychromatic tables that are inaccessible for memorization.

Anomaloscopes are devices based on the principle of achieving a subjectively perceived equality of colors by metered composition of color mixtures. The classic device of this type, designed to study congenital disorders of the perception of red-green colors, is the Nagel anomaloscope. By the ability to equalize a half-field of monochromatic yellow with a half-field composed of a mixture of red and green colors, the presence or absence of normal trichromacy is judged.

The anomaloscope allows diagnosing both extreme degrees of dichromasia (protanopia and deuteranopia), when the subject equates red or pure green color to yellow, changing only the brightness of the yellow half-field, and moderate disorders in which the mixture of red and green is perceived as yellow (protanomaly and deuteranomaly ). According to the same principle as the Nagel anomaloscope, the anomaloscopes of Moreland, Naitz, Rabkin, Besancon and others were built.

Violations of color perception are a contraindication for work in some industries, a driver in all modes of transport, service in some types of troops. Normal color vision is necessary for the maintenance of conveyors, manual service trainers, etc.

T. Birich, L. Marchenko, A. Chekina

"Color vision disorders"- article from the section

Color vision (color perception) is an important function of the organ of vision, due to the ability to distinguish between light waves of the spectrum range.

The three primary colors (red, blue and green) are the basis of all color shades that the human eye can distinguish.

color signs

When characterizing different colors, the following signs are used:

• Color tone is the main indicator that depends on the wavelength of the radiation.
• Brightness - the degree of dilution of a given color by white.
• Saturation - the degree of manifestation of the main tone.

The role of color perception

Color vision is very important in various areas of human life. Many professions require the ability to distinguish colors, for example:

• For drivers and machinists (colors of traffic lights).
• For doctors (many symptoms are associated with discoloration of the skin, mucous membranes, fundus).
• For chemical scientists (carrying out color chemical reactions).

Also, the ability to distinguish color shades affects the emotional background of a person.

A large role in the study of color perception belongs to Lomonosov (XVIII century), Jung (early XIX century) and Helmholtz, on the basis of whose work the theory of the three-component color vision was formed. According to her, color perception is due to the activity of cones, which are divided into three groups (depending on the sensitivity to light of a certain range of the spectrum):

• Red.
• Blue.
• Greens.

When light hits the retina, all three types of cones are excited, but in varying degrees, which determines the perception of different colors by the eye.

Color vision disorders

All disorders and disorders associated with color perception can be either congenital or acquired.

Normally, a person distinguishes all three primary colors (red, green and blue), this norm is trichromasia.

If a person’s perception of any one color falls out, then this pathology is called dichromasia.
. It is distinguished by the following types:

• Protanopia - a person completely does not perceive the color red.
• Deuteranopia - green color disappears from perception.
• Tritanopia - a person cannot see the color blue.

Discovered by the scientist Dalton, who had this pathology (protanopia) and first described it. Therefore, any violation of color perception is called the term "color blindness".

When the patient sees everything around in one color, they talk about monochromacy, which in turn is divided into:

• Erythropsia - vision in red.
• Xanthopsia - a person sees everything in yellow.
• Chloropsia - vision of the world around in green.
• Cyanopsia - the patient sees everything around in blue.

The most rare, or achromatopsia (violation of the activity of all types of cones), is a vision in black and white.

Methods for the study of color anomalies

When examining disorders of color anomalies, polychromatic tables and special devices, anomaloscopes, are most often used.

The tables show numbers and various figures, consisting of circles of a certain color, while the background has a different color. If the patient does not distinguish figures of any one color, then he has a pathology of color perception.