Features of human color vision

Vision is one of the most important feelings for perception of the world around us.With it, we see objects and objects around us, we can estimate their size and shape. If we believe in research, with the help of vision, we get at least 90% of information about the surrounding reality.For color vision, several visual components respond, which allows more accurate and accurate transmission of images of objects in the brain for further processing of information.There are several abnormalities in the transmission of colors that significantly degrade interaction with the world and reduce the quality of life in general.

How is the organ of vision organized?

The eye is a complex optical system, which consists of many elements connected together.Perception of various parameters of surrounding objects (size, distance, shape, etc.) provides the peripheral part of the visual analyzer, represented by the eyeball. It is a globular organ with three shells, which has two poles - the inner and the outer. The eyeball is placed in a three-sided bone cavity - the eye socket or orbit, where it is surrounded by a thin fat layer. In front are the eyelids needed to protect the mucous membrane of the body and its purification. It is in their thickness that there are glands necessary for the constant moistening of the eyes and for the unobstructed work of closing and opening immediately the eyelids. Movement of the eyeball provides 6 different in the functions of the muscles, which allows you to perform friendly actions of this pair body.

In addition, the eye is connected to the circulatory system by numerous numerous blood vessels, and with the nervous system - by several nerve endings.

The peculiarity of vision is that we do not see the object directly, but only the rays reflected from it. Further processing of information occurs in the brain, more precisely its occipital part. Rays of light initially enter the cornea, and then pass to the lens, vitreous body and retina. Зand the perception of the rays of light corresponds to the natural lens of a person - the lens, and for its perception the photosensitive membrane - the retina is responsible.It has a complex structure in which 10 different cell layers are isolated. Among them, cones and rods that are unevenly distributed throughout the layer are particularly important. It is the cones that are the necessary element, which is responsible for the color vision of the person.

The greatest concentration of cones is noted in the central fovea - the perceiving image of the region in the yellow spot. Within its limits, the cone density reaches 14, 00. on 1 mm2.

Color perception

The human eye is the most complex and perfect visual system among all mammals.He is able to perceive more than 150 thousand. different colors and their shades.The perception of color is possible thanks to the cones - specialized photoreceptors located in a yellow spot. The auxiliary role is played by rods - cells responsible for twilight and night vision. To perceive the entire color spectrum is possible with the help of only three kinds of cones, each of which is susceptible to a certain area of ​​the color gamut (green, blue and red) due to the content in them iodopsin.A person with full vision has 6-7 million. cones, and if their number is less or there are pathologies in their composition, different color disturbances arise.

Structure of the eye

The vision of men and women is very different. It is proved that women are able to recognize more different shades of colors, while representatives of a strong sex have a better ability to recognize moving objects and to retain concentration for a longer object.

Color vision abnormalities

Color vision anomalies are a rare group of ophthalmic disorders, which is characterized by a distortion of the perception of colors.Almost always, these diseases are inherited by recessive type. From a physiological point of view, all people are trichromates - to fully distinguish color use three parts of the spectrum (blue, green and red), but with pathology, the proportion of the flowers or some of them is completely or partially falls out.Color blindness is only a special case of pathology, in which there is complete or partial blindness to any color.

There are three groups of color vision anomalies:

• Dichromatism or dichromasia. The pathology is that only two regions of the spectrum are used to obtain any color. There is a large number of dichromatic disorders, depending on the drop-out section of the color palette. The most common is deuteranopia - the inability to perceive the green color;
• Complete color blindness. It occurs only in 1% of all people. There are two types of pathology:Achromatopsia (achromasia), which completely lacks the pigment in the cones on the retina, and any colors are perceived as shades of gray, andcone monochromasia- Different colors are perceived identically. The anomaly is genetic and is associated with the fact that in the color photoreceptors, instead of iodopsin, there is rhodopsin;

Read more about what it is achromatopsia.

• Nictalopia ("night blindness") or gemeralopia. A rare violation of the cone apparatus, in which there is a partial or complete lack of the ability to see and distinguish colors in low light and at dusk. It is believed that the anomaly arises from a lack of vitamin A and PP in the body or can occur with pathologies of intrauterine development. Hemeralopia was originally described as the inability to distinguish colors in daylight, but because of the confusion with terminology today, both names are synonymous.

Any color deviation is the cause of many restrictions, for example, for driving vehicles or service in the army. In some cases, anomalies of color perception are the cause of the disability in sight.

Definition and types of color blindness

One of the most frequent pathologies of color perception, which is of a genetic nature or develops against the backdrop of severe retinal diseases. There is a complete (achromatic) or partial impossibility (dichromasia and monochromasia) to perceive colors, more details of pathology are described above.

Traditionally, several types of color blindness are distinguished in the form of dichromate, depending on the fall of the color spectrum.

• Protanopia. There is a color blindness of the red portion of the spectrum, occurs in 1% of men and in less than,% of women;
• Deeranopia. From the perceived gamma of colors, the green portion of the spectrum falls out, occurs most often;
• Tritanopia. The inability to distinguish between the shades of blue-violet color, plus there is often a lack of twilight vision due to irregularities in the operation of the rods.

Isolate trichromasia.This is a rare kind of color blindness, in which a person discerns all colors, but because of a violation of the concentration of iodopsin, the color perception is distorted. Particular difficulty is experienced by people with this anomaly in the interpretation of shades. In addition, often the effect of hypercompensation is observed in this pathology, for example, when it is impossible to distinguish between green and red, an improved discernment of the khaki shades appears.

Types of color blindness

The anomaly bears the name J. Dalton, who described the disease back in the 18th century. Great interest in the disease is due to the fact that the researcher and his brothers suffered from protanopia.

The test for determining color blindness

In recent years, to determine color perception anomaliesRubkin's polychromatic tables are used, which represent figures of figures and figures applied to a selected background using various circles of diameter. In total, 27 pictures have been developed, each of which has a definite purpose. Plus, in the stimulus material, there are special images for detecting the simulation of the disease, because the test is important in the passage of some professional medical commissions and when military registration.Interpretation of the test should be carried out only by a specialist, since the analysis of the results is a rather complex and time-consuming process.

It is believed that only printed cards can be used, since color distortion can occur on the monitor or screen.

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conclusions

The human vision is a complex and multifaceted process, for which many elements respond.Any anomalies of perception of the surrounding world not only reduce the quality of life, but can be a threat to life in some situations. Most visual pathologies are congenital, so when diagnosing a child, the deviation is not only go through the necessary treatment and correctly pick up corrective optics, but also teach him to live with this problem.

Also read about whether it is possible to cure color blindness?