In this article we will tell you:
- Colorblindness - what is it?
- Mechanism of anomaly
- Forms and types of color blindness
- Causes of color blindness
- Diagnosis of color blindness
- Correction of color blindness
Color blindness is probably one of the most famous ophthalmological diseases: both jokes and aphorisms are dedicated to it. However, most often they do not reflect the essence of the disease: therefore, in people’s minds it is often associated with symptoms and features that are unusual for it.
Read about what color blindness actually is, what its nature and mechanisms are, what types of color blindness there are, and whether there are ways to cure it.
Color blindness: a detailed description of the condition
Color blindness, about which much has been written on Wikipedia, is not a separate disease. This concept unites a whole group of color vision disorders, and individual varieties have different characteristics.
Colorblindness is popularly called color blindness, but this is not entirely true. Complete color blindness implies the absolute inability to see and distinguish any colors and shades, that is, a black and white perception of the world. But this is not the only form of color blindness. Much more often, so-called partial color blindness occurs, in which a color-blind person does not distinguish and confuses only certain tones.
Most often, colorblind people cannot distinguish at all or distinguish poorly and confuse any primary color of the palette. A person sees objects painted in this shade as different, for example, gray, dark brown, black (depending on the form of pathology). In certain forms of color blindness (complete color blindness), the color blind person cannot see absolutely any colors and tones, that is, he does not simply confuse them, but perceives objects in a grey-white-black range.
Interesting fact! According to world statistics, color blindness is much more common in men. Thus, among representatives of the fairer sex, impaired color perception occurs only in 0.4-0.5%. Men tend to confuse colors with color blindness in 5-9% of cases.
But what is color blindness, why does it develop? The mechanism of development of this pathology lies in the structure of the retina of the eye - the retina. It contains photosensitive special receptors that perceive light rays - cones and rods. Cones are responsible for color perception: they contain specific color-sensitive pigments of protein origin, divided into three separate types. Thanks to such cells, a person is able to see and easily distinguish between different shades and not confuse them.
Cones, depending on the pigments they contain, are responsible for the perception of three colors: green, blue and red. They are the main ones, and all other shades are formed by mixing the basics of the spectrum. Rods allow you to see objects in black and white in twilight or poor lighting conditions.
Cones capture and perceive light rays reflected from various objects. Color (blue, green or red spectrum) is determined by the length of the light wave, as well as the angle of its reflection from the surface. The receptors receive the signal received on the retina and send it along the optic nerve through nerve impulses to the brain, where all the information is processed and gives the person an idea of what and in what shade he sees.
With color blindness, the cones do not function correctly, which is why the task of color perception is not fully performed. Photosensitive receptors may not contain pigments at all, and in this case, a color blind person, due to color blindness, is unable to see and distinguish primary colors. Most often, one type of pigment is missing, so a person does not distinguish only one main part of the spectrum: either red, green, or blue.
If pigment protein compounds are present in the cones, but their concentration is insufficient for normal color perception, then the colorblind person will confuse the shades and see them differently than other people (for example, dull, excessively dark or grayish).
There is also another option for the development of color blindness. In this case, color incomplete blindness is accompanied by disturbances in the arrangement of pigments in photosensitive receptor cells. That is, the pigment is present, and there is enough of it, but it is not in the cones in which it should be. Because of this, colorblind people with this form of color blindness cannot see the entire gamut, do not distinguish between individual components of the spectrum, and confuse different shades. The picture of the world is perceived differently.
Good to know! Depending on what specific colors the colorblind person does not see, does not distinguish and confuses, there are several types of color blindness. There are dichromasia, protanopia, achromasia, tritanopia and other varieties.
Historical reference
Wikipedia and other sources contain information that color blindness was first described many years ago - in 1794. A scientist from England named John Dalton, at the age of 26, noticed that he was unable to distinguish certain colors. In his case, the disorder was hereditary in nature, since signs also appeared in his siblings.
Dalton published his own scientific work describing color blindness and gave the phenomenon a name in honor of his last name. The scientist made a huge contribution, since further color blindness and various forms of disorders (protanopia, tritanopia and others) began to be actively studied.
What do colorblind people see?
Source: doctorfm.ru
Color blindness is a hereditary vision defect, not a disease. People with this defect see well, but slightly differently than others.
Deviations in color perception in a person do not allow us to say that the person is unhealthy. We can only say that a given person has his own color perception of the world around him, different from the color perception of other people.
History has taught us many times that all brilliant people perceived the world around them, nature and phenomena differently from everyone else. It is to them that we owe new discoveries and inventions.
Those who are color blind and people with reduced color vision perceive the colors of the world around them differently than we do, but often do not notice their difference from others. Sometimes people around him don’t even notice him.
After all, these people from childhood learn to call the colors of everyday objects with generally accepted designations. They hear and remember that grass is green, the sky is blue, blood is red. In addition, they retain the ability to distinguish colors by degree of lightness.
Types of color blindness
Protanopia, total color blindness, and tritanopia are just a few distinct forms of color blindness, but other types also exist. So, according to Wikipedia and other sources, depending on the number of colors that a colorblind person is able to distinguish, dichromasia, trichromasia, monochromasia and achromasia (complete color blindness) are distinguished. Each of these types of color blindness is worth writing separately and in detail.
Trichromasia
With trichromasia, unlike protanopia and tritanopia, a person is able to see all three primary colors of the spectrum. There is normal trichromasia and also abnormal trichromasia. In the first case, a person is not considered colorblind, since he distinguishes colors, sees them correctly and does not confuse them.
With abnormal trichromasia, as with protanopia and tritanopia, there are deviations from the norm and clearly impaired altered color perception. Although a person is able to distinguish all colors and not confuse them, he sees them not so bright and intense. Colorblind people may perceive shades as faded, dull, dark or, on the contrary, excessively light.
Depending on the component of the spectrum, the color perception of which is distorted and impaired, the following forms of anomalous trichromasia are distinguished:
- Protanomaly (sometimes incorrectly called protanopia), which affects the perception of bright red hues.
- Deuteranomaly, characterized by the inability to adequately and fully perceive and differentiate shades of green.
- Tritanomaly (sometimes incorrectly called tritanopia), in which colorblind people cannot distinguish between blue and violet tones.
Achromasia
Achromasia is complete color blindness, in which color perception is completely absent, that is, a colorblind person sees all objects as black, gray or white. In its cones located on the retina (all three types) there are no pigments at all, so a person with such disorders cannot distinguish any colors. This type of color blindness is extremely rare.
Monochromacy
This type of color blindness is characterized by disruptions in color perception, in which a person is able to see and distinguish only one color of the gamut: only blue, only green, or exclusively red. This form is quite severe, often accompanied by concomitant pathologies, for example, high photosensitivity or photophobia, as well as nystagmus - involuntary, chaotic, uncontrolled, very fast and frequent oscillatory movements of the eyeballs.
Dichromasia, including protanopia, tritanopia and deuteranopia
Dichromasia, which includes separate forms of tritanopia, deuteranopia and protanopia, is a separate type of color blindness in which a person distinguishes two colors out of three possible. These can be any shades that are perceived by cones with color-sensitive pigments.
Dichromasy includes three distinct forms:
- Protanopia. The name protanopia comes from the Greek language, and “protos” is translated as the first (red was conventionally considered the first and main color of the spectrum). This deviation is the most common and occurs more often than others. Protanopia is characterized by incorrect color perception of shades of red. A colorblind person can see objects painted in this color as brown, gray, sometimes black, rarely dark green.
- Deuteranopia (“deteros” is translated from Greek as “second”). With this variety, a colorblind person does not perceive green tones, and he sees them as pinkish, pale orange.
- Tritanopia. The name is also Greek, “tritos” is the third, and that is the color blue. Tritanopia is a rather rare type of color blindness, the symptom of which is the lack of color perception of violet and blue gamuts. At the same time, the shades of red and green differ well. With tritanopia, the functioning of the rods located on the retina is also impaired, causing twilight vision to deteriorate.
Interesting fact! In some cases, color vision impairments are compensated by nature. For example, a colorblind person with protanopia, the main symptom of which is a violation of the color perception of the red gamut, is not able to differentiate red tones, but perceives shades of blue and green better, brighter and more acutely. And with tritanopia, the red and green gammas are clearly distinguishable.
Reasons for development
Wikipedia, as well as other reliable sources, says that most often protanopia, tritanopia and other types of color blindness are congenital. That is, the main reason is hereditary predisposition. The anomaly is formed at the stage of intrauterine development of the fetus due to a “broken” X chromosome. The carrier of the defective gene can be either a woman or a man, and sometimes color blindness is passed on through generations.
If a woman is the carrier of the defective gene, then she is likely to pass on color blindness to her son, but at the same time she herself can be completely healthy. In males, the “breakage” in the only X chromosome cannot be compensated for, since there is no other X chromosome. And that is why among men, deviations are 15-20 times more common.
For your information! There are also some congenital diseases in which the structure of the cones is disrupted. This happens with retinitis pigmentosa, pathological cone dystrophy or Leber amaurosis.
Acquired color blindness (including protanopia) occurs against the background of certain traumatic or thermal damage to the visual organs, as well as eye pathologies and diseases: cataracts, retinopathy in diabetes mellitus, glaucoma. Less commonly, altered color perception develops for other reasons - as a result of taking certain medications, Parkinson's disease, severe poisoning and intoxication, stroke and brain damage (occipital lobe).
Acquired color vision problems
Source: bolvglazah.ru
Acquired color vision problems have many causes:
- Aging can increase the chance of color vision problems. As a result of the darkening of the lens with age, people have difficulty perceiving the differences between dark blue, dark green and dark gray.
- Side effects of certain medications can cause temporary or permanent color vision problems.
- Certain eye diseases, such as glaucoma, macular degeneration, cataracts, or diabetic retinopathy, can cause temporary or permanent color vision problems. Treatment for these conditions can help maintain or restore color vision.
- A wound in the eye, especially in a part such as the retina (spot) or the optic nerve, can cause color vision problems.
The main manifestations of color blindness
What is the main sign of color blindness? How do colorblind people see colors, what colors can they not distinguish? This is written about on Wikipedia and in scientific works, and each case is individual. It all depends on what type of color blindness is diagnosed: tritanopia, anomalous trichromasia, protanopia or some other.
With complete color blindness, the picture of the world is perceived as black and white with gray transitions. With protanopia, tritanopia and deuteranopia, the color perception of objects is more vibrant and varied, but incorrect and different from the norm. Thus, protanopia is accompanied by the inability to differentiate the red gamut, deuteranopia – green, and tritanopia – violet and blue. What shades replace the indistinguishable tones? This depends on the structural features of the retina, namely its cones with color-sensitive protein pigments. The more such substances there are, the brighter and more diverse the spectrum.
Advice! In the photo and various images you can see how the colors of the world are approximately perceived by colorblind people with protanopia, achromasia, tritanopia, monochromasia and other varieties.
Professional restrictions
Despite the fact that a person with color blindness is not disabled, he is prohibited from entering a number of organizations and areas. A mandatory test for color perception is carried out when recruiting for aviation, marine and other industries where it is vital to be able to distinguish colors. At the same time, colorblind people became allowed to drive a car in Russia quite recently - only monochromatic people are not allowed to get a license. It should also be said that colorblind people are better at distinguishing related shades - for example, they are more successful at deciphering camouflage.
Diagnostics
To identify protanopia, tritanopia or other forms in men and women, you must contact an ophthalmologist for a specific diagnosis. The specialist conducts special tests.
Protanopia or tritanopia is usually immediately determined by testing using Rabkin's polychromatic tables. This method, developed in the middle of the last century, involves examining cards with various symbols. But the figures with numbers and backgrounds are not uniformly colored, but are created from small dots of different sizes and shades. If a person can easily determine what is shown on the card, he is doing well. If the test taker cannot see the symbols, then he is likely to have color blindness (protanopia, tritanopia, or another type). The Yustova, Ishihara and Stilling tests work on almost the same principle.
To identify color blindness, you should undergo testing, following several rules: keep images at eye level and at a meter distance, avoid bright lighting, look at signs for no longer than 5-7 seconds, remain in a calm and healthy state, and also use only paper media (screens). gadgets distort pictures).
Other diagnostic techniques are also used: the Holmgren method with the distribution of threads across three spectra of colors, the Falant test (studying the light of a lighthouse and two colored lanterns), as well as instrumental methods using specialized equipment developed by Nagel, Emney, Rabkin and Girenberg (spectroanomaloscope, anomaloscope and other patented devices).
Persons with acquired forms of color blindness are also advised to use other diagnostic procedures to assess the condition and structure of the visual organs: tonometry, biomicroscopy, refractometry, perimetry, ophthalmoscopy, ultrasound and others.
Color blindness in children
Sometimes a man or woman discovers their peculiarity already in adulthood; impaired color vision is also diagnosed in school-age children during routine examinations. Often the diagnosis is made accidentally and suddenly, since a colorblind person may simply not know about the deviations if he sees the world in a certain way from birth and simply does not know other options for perception.
In most cases, color blindness is congenital, that is, it manifests itself immediately. But in the first months and even years, a small child is not able to clearly describe what he sees. And the ability to differentiate individual colors and tones is finally formed only by three or four years. But even at this age, diagnosis is complex and problematic, because even with protanopia or tritanopia, the child can describe some objects correctly. The sky will be blue, the blood will be red, and the grass will be green, because this is what your parents taught you. But how colors actually appear and are perceived by the eye is very difficult to determine.
To suspect tritanopia, achromasia, protanopia or another type of impaired color vision, you need to pay attention to the child’s behavior while drawing, modeling from plasticine or cutting out figures from colored paper. Parents can ask their son or daughter to make some object or character. And if a red apple turns out to be brown, then there is a chance that protanopia is present. And if the sea is not depicted as blue, then tritanopia can be suspected.
A young child usually does not experience difficulties if he has color blindness, which is not yet known. But in kindergarten, and even more so at school, problems can arise. To avoid difficulties, it is important to identify protanopia, tritanopia, deuteranopia or another type as early as possible, and after diagnosis, talk to the child and tell him that the feature distinguishes him from other people, but does not make him worse or ruin his life if he learns to adapt.
Interesting Facts
- Most applications and operating systems are made in blue tones for a reason. After all, it is this spectrum that is best determined for various types of color blindness.
- Researchers have found that colorblind people see camouflage fabric better, so it is possible that people with these qualities will be accepted into the reconnaissance forces.
- Among the famous colorblind people there are great artists. Van Gogh, for example, did not accidentally use so much yellow in his paintings. And many researchers of the work of the Russian artist Vrubel come to the conclusion that the creator had a violation of the perception of red and green colors, which is why the paintings are of such restrained tones.
Color blindness does not affect the clarity of vision, but with a significant impairment of color vision, it impairs the perception of surrounding information.
With proper observation, timely diagnosis and correction, the patient will be able to regain the bright colors of life! Take care of your eyesight!
Treatment
Is there a cure for color blindness? Congenital protanopia, tritanopia and any other type cannot be treated, but can be corrected. Specialized glasses with tinted lenses, thick frames or side shields are used to reduce the intensity of light that interferes with the perception of colors.
An innovative high-tech optical device with multilayer lenses that corrects the perception of primary colors has been developed in America. A huge breakthrough in treatment was made by the release of equipment that enhances the main parts of the spectrum and mutes or blocks halftones and shades.
There is a method for treating protanopia and other forms that is under development and has only been tested on monkeys. It involves the introduction of structure-changing viral particles into defective genes.
Acquired color blindness involves treatment of the underlying disease that impairs color perception. When the main reason for the change in color perception is eliminated, the functioning of the cones with color-sensitive pigments can be completely restored and normalized, if the violations were not irreversible.
