The main types of color blindness

Among various ophthalmic diseases, color blindness remains one of the most common.A similar pathology can occur in people of different ages. As a result, they are not able to distinguish certain colors. Because of this, a person is not able to see in an exact color some objects, which complicates life.

Definition of disease

Color blindness is a pathological process that leads to a violation of the normal perception of certain colors.As a rule, pathology has a genetically determined nature, but it can occur against the background of diseases of the retina, optic nerve.

The mesh shell of the organ of vision is a layer of nerve cells that are capable of perceiving rays of light, and then send the information received through the optic nerve to the brain.

This disease was first described in detail by John Dalton, who himself could not distinguish the colors of the red spectrum. He found this visual impairment only by the age of 26, which served as the basis for the creation of a small publication in which he described in detail the symptoms of the disorder. Remarkably, his two brothers of three and his sister also had deviations in this color spectrum.

After the publication of the book in medicine, the term "color blindness which describes this pathology not only within the framework of red, but also blue and green, was affirmed for a long time.

Types and Classifications

The cause of the violation of color perception is the deviation in the work of the retina.In its central part, the macula, there are color-sensitive receptors, which are called cones. In total, there are three types of cones that react to a certain color spectrum. Normally they work in a coordinated manner and the person fully differentiates all colors and shades, their intersection. If one of the types is violated, one or another type of color blindness is observed.

The shape of rods and cones

Distinguish complete and partial blindness on a certain spectrum. For example, tritanopia - the complete absence of cones responsible for the perception of blue, tritanomalia - a partial lack of cones, when a person sees blue as muffled.

At the genetic level, if there is a color blindness carrier, this leads to a disruption in the production of one or more color-sensitive pigments. Those who see only two colors of the three are called dichromates. People with a full set of cones - trichromate.

Initially classify by the type of acquisition of the disease: congenital and acquired.

Congenital

This kind of color blindness, as a rule, affects both eyes, has no propensity to progress and is observed predominantly in men, tk. is inherited through the X chromosome from mother to son.

This form of color blindness is most common in men than in women.

For women, inheritance of daltonism on the paternal line from the mother of the father and his grandmother is characteristic.

Statistics argue that the frequency of manifestation of color blindness in women %, and in men - 2-8%.

Congenital color blindness is divided into trichromasia and dichromasia:

1. TrichromasiaIs a deviation in which the functioning of all three types of cones is retained, but significantly reduced. With this anomaly, color recognition is established, but it is impossible to distinguish most shades.
2. Dichromasiacharacterized by the absence or termination of the functioning of one type of cone.
3. Achromasia(achromatopsia or monochromasia) is diagnosed when a person does not completely distinguish all three color spectrums. His vision is limited only by black and white colors. A fairly rare deviation is observed only in% of cases.

Types of color blindness

Dichromasia is divided into protanopia, deuteropia and tritanopy.

1. Deeranopia- the inability to distinguish colors and shades of green.
2. Tritanopia- the inability to see the colors and shades of the blue spectrum.
3. Protanopia- Absence of perception of colors and shades of a red spectrum.

Also in medical practice, the term "anomalous trichomatism" occurs.This name means a decrease, but not absence, of the perception of a certain spectrum of colors, as described earlier, and distinguish such deviations:

1. protanomaly, proceeding from protanopia, a violation of perception of red color;
2. tritanomalia- blue;
3. deuteranomalia- green.

Abnormal trichomatosis can be acquired.

Congenital color blindness does not respond to treatment and the life of the patient affects only in terms of choosing a profession.No specific diseases, this pathology for itself does not attract, as well as not established disability. The only exception is the monochromasia article.

An example of a color blindness with monochromasia

Currently, studies are in progress in the field of the treatment of color blindness, and so far the only way to correct the anomaly is the use of special glasses.But again, their action is quite difficult to describe, because the color blind is not able to determine a particular color, depending on the type of deviation.

Acquired

This form of color blindness is characterized by damage to the retina of the organ of vision or the optic nerve.The disease is diagnosed in the same way in women and men. Affect the development of acquired color blindness can damage the retina with ultraviolet light, head trauma, and the use of medications. For the acquired form of color blindness, there are difficulties in distinguishing between yellow and blue.Cataracts can also lead to the development of this pathology.

External manifestation of cataracts

Acquired color blindness is classified into:

1. Xantopsy- a deviation in which a person sees the world in yellow shades. Pathology is based on such transferred diseases as jaundice (deposition of bilirubin in the tissues of the eye due to a strong yellowness sclera), atherosclerosis, intoxication with medicines, etc.
2. Erythropsy- a characteristic pathology for people suffering from retinal diseases (retinoschisis, detachment, dystrophy), when the world is represented in red shades due to the excessive number of red corpuscles on the surface of the macula.
3. Trianotopia- often occurs in people suffering from night blindness (hemeralopia). The cones responsible for the blue color are damaged.

This form of the disease is treatable in some cases by completely eliminating the cause of its occurrence.

Diagnostic Methods

One of the most famous methods for diagnosing color blindness are the polychromatic tables of Rabkin.The tables contain colored circles of equal brightness. From the circles of one shade, various figures and geometric figures are drawn on the images. By the number and color of figures determined by man, one can judge the degree and form of color blindness.

Rabkin's Table

You can use the simpler tables of Stilling, Justova and Ishihara.They were obtained by calculation, not experimental. Doctors use the Holmgren method. According to him it is necessary to disassemble the coils with colored woolen threads along the three main colors.

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conclusions

Color blindness is a dangerous disease that does not allow a person to fully distinguish colors.Because of this, his habitual rhythm of life is broken. You can treat color blindness. But here it is necessary to start from the degree and type of the pathological process. There is a form of illness that does not respond to therapy and all that remains to the patient is to reconcile with the diagnosis and adapt to a new life.