Daltonism in a person: causes, how to check

Color blindness is a special type of vision disorder that manifests itself in the absence of perception of certain colors, most often green, red and violet. Basically, color blind people are unable to distinguish a certain color or several colors. But there are also such types of color blindness when the patient does not identify a single color - complete color blindness. Theoretically, only men are susceptible to this disorder. However, statistics say that 0.4 - 0.5% of women suffer from color blindness due to various retinal injuries.

Causes color blindness

There are two causes of color blindness:

• Heredity

Color blindness is linked to the X chromosome and is passed on from the carrier mother to her children. There are often cases of congenital distortion of perception of some colors, but at the same time the patient can recognize and distinguish other colors and shades that are difficult to distinguish for an ordinary person. Read about cases of color blindness in women in this article.

• Retinal trauma

Color blindness develops due to damage to the retina and optic nerve.

In the center of the retina of the eye there are special cells whose main function is to perceive color. These cells are called cones. Three types of cones are involved in the retina, each of which contains a protein substance (pigment) that captures its genetically determined color: green, red or blue. The cones of a healthy person contain all three pigments. Cones in pathologies are deprived of pigment or have an inferior pigment.

• Pathology of the optic nerve

With neuritis and atrophy of the optic nerve, there is a decrease in color perception depending on the degree of damage to the visual analyzer.

• Age-related visual impairment associated with lens opacity
• Consequences of taking certain medications (digitoxin, ibuprofen)

The use of foxglove-based drugs causes visual impairment due to its accumulation in the blood plasma and retina. Statistics show that 25% of cases of side effects from taking digitoxin manifest themselves in visual impairment and color perception (appearance of blue-yellow or red-green spots before the eyes, reflection of objects in shades of yellow).

How is color blindness inherited?

Color blindness is inherited and manifests itself only in men. This is due to the fact that the color blindness gene is linked to the X chromosome. As is known, female chromosomes are represented as XX, and male chromosomes as XY. It follows that damage to the X chromosome in men inevitably causes the disease, while damage to the female X chromosome is compensated by another X chromosome, so the disease does not manifest itself. The woman acts as a carrier of the disease, which she passes on to her children through the genotype.

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Risk factors

The main risk factor is the presence of color blindness in close relatives, especially in the mother.

The likelihood of developing color blindness increases significantly in people with a history of mechanical trauma and retinal burns. Such aggressive exposure can cause a sharp or gradual deterioration of color vision.

Color blindness may occur as a result of taking cardiac glycosides, long-term and uncontrolled use of non-steroidal anti-inflammatory drugs, and narcotic substances (hallucinogens initially cause an exacerbation of color vision, after which it may be weakened for some time).

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Symptoms color blindness

The main and only symptom is the inability to distinguish certain colors.

The first signs of hereditary color blindness may be detected in adolescence, for example during a medical examination to obtain a driver's license. Congenital color blindness is perceived by the patient as normal, since he is not aware of the presence of other colors.

In childhood, the only symptom of color blindness is the inability to distinguish the colors of surrounding objects. If you ask a child to choose a red toy from the toys on offer, he or she will not be able to cope with this task.

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Forms

There are two types of color blindness:

1. hereditary;
2. acquired.

Congenital color blindness is inherited from the carrier mother.

Acquired color blindness occurs as a result of eye injuries and damage to the integrity of the structures responsible for color recognition.

The inability to distinguish all colors is called monochrome color blindness. In this condition, the patient sees the surrounding world in gray and black and white tones.

Complete insensitivity to colors is called achromasia. This type of color blindness is very rare.

Partial color blindness is the inability to see one or two colors, such as green and red or blue and yellow parts of the spectrum.

There is another similar concept - "emotional color blindness". This term refers to psychiatry and has nothing to do with vision. Emotional color blindness is the inability of a person to adequately perceive the full variety of emotions. Such a person can evaluate an emotion only in terms of good and bad.

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Complications and consequences

The consequences and complications of color blindness directly depend on the cause of its occurrence. Congenital color blindness can remain at the same level for life. Acquired color blindness can develop into more severe pathologies in the absence of treatment and prevention.

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Diagnostics color blindness

Rabkin tables are used to diagnose color blindness. The tables depict circles of different colors, but with the same brightness. These circles form a solid background and a geometric figure (number) in the center of the table. In total, the patient is asked to look at 27 cards. The image that a healthy person sees differs from what a person with visual impairment sees. The test is used to determine the type of color blindness.

Another informative study is the Ishirah test. The test also includes the use of special cards with pictures that a person with normal vision can recognize (90% correct answers). A person with color blindness will not be able to recognize the images or will cope with the task partially (5 - 30% correct answers).

The third diagnostic method is spectral. Rabkin's spectroanamaloscope is used for the study. This device has two color fields. One field is yellow, and the other field is red and green. The patient is asked to equalize the colors so that the red and green in the second field become yellow. The presence of color blindness prevents normal evaluation of the color spectrum.

Using the above methods, a color blindness test is conducted for drivers.

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Differential diagnosis

Differential diagnostics are performed to exclude various types of retinopathies or retinal atrophy. In the early stages, retinal pathology may manifest itself in impaired color perception and have symptoms similar to color blindness. Then the disease progresses, which can lead to partial or complete blindness. Diagnosis is made using ophthalmological methods and collecting family history.

Treatment color blindness

There is currently no specific therapy for the treatment of color blindness. Scientists have put forward a theory about the feasibility of using genetic engineering by inserting missing genes into the cellular apparatus of the retina. This technique will significantly improve color vision with a minimal chance of relapse.

In case of retinal dystrophies, eye drops Taurine, vitamins of group B and capsules Aevit are prescribed. These drugs in combination improve ocular blood circulation, normalize oxidation-reduction processes and tissue trophism.

There are special glasses for color blindness. They look like regular sunglasses and are designed for everyday wear. The lenses of these glasses are multilayer lenses, which include a special substance - neodymium oxide. The glasses help a person to optimally distinguish colors, but do not have the potential for full vision.

Prevention

To prevent complications, it is necessary to undergo regular routine examinations by an ophthalmologist and eliminate factors that adversely affect the retina (long-term work at the computer, bright light, taking certain medications). The main goal of prevention is to avoid eye strain.

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Colorblindness and driving licenses

Since 2000, the Ministry of Health has issued a decree banning colorblind people from driving vehicles. This decision is based on many factors that can cause an accident.

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Color blindness and the army

Color blindness is not included in the list of diseases that give the right to a deferment or exemption from military service.

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Where can you work with color blindness?

With a diagnosis of color blindness, it is prohibited to work with any vehicles and mechanisms that require the use of color perception. For other professions, color blindness is not an obstacle.