Definition of disease
Color blindness is a pathological process that leads to disruption of the normal perception of certain colors. As a rule, the pathology is genetically determined, but can occur against the background of diseases of the retina and optic nerve.
The retina of the organ of vision is a layer of nerve cells that are able to perceive rays of light, and then send the received information 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 discovered this vision defect in himself only at the age of 26, which led to the creation of a small publication in which he described in detail the symptoms of the disorder. What is noteworthy is that two of his three brothers and a sister also had deviations in this color spectrum. After the publication of the book, the term “color blindness” was established in medicine for a long time, describing this pathology not only in terms of red, but also blue and green.
Does it occur in women?
Many people are interested in whether girls are color blind? This disease rarely occurs in the fair sex and is often accompanied by other visual impairments. Considering that the disease can be inherited, even young girls can be colorblind.
There are cases when color blindness is an acquired disease. This may be a consequence of severe poisoning of the body, trauma to the visual organs, atrophy of the optic nerve and natural aging of the body. The acquired form of the disease occurs equally often in women and men.
Types and classifications
The cause of color vision impairment is a deviation in the functioning of the retina. In its central part, the macula, there are color-sensitive receptors called cones. There are three types of cones that respond to a specific color spectrum. Normally, they work harmoniously and a person fully distinguishes all colors and shades, their intersection. If one of the types is violated, one or another type of color blindness is observed.
There are complete and partial blindness along a spectrum. For example, tritanopia is the complete absence of cones responsible for the perception of blue color, tritanomaly is a partial absence of cones, when a person sees the blue color muted.
At the genetic level, if there is a carrier of color blindness, this leads to a disruption in the production of one or more color-sensitive pigments. Those who see only two colors out of three are called dichromats. People with a full set of cones are trichromats.
Initially, they are classified according to the type of acquisition of the disease: congenital and acquired.
Congenital
This type of color blindness, as a rule, affects both eyes, has no tendency to progress and is observed mainly in men, because inherited via the X chromosome from mother to son.
This form of color blindness is more common in men than in women.
Women are characterized by paternal inheritance of color blindness from their father's mother and his grandmother.
Statistics say that the incidence of color blindness in women is 0.4%, and in men – 2-8%.
Congenital color blindness is divided into trichromasia and dichromasia:
- Trichromasia is a disorder in which the functioning of all three types of cones is preserved, but significantly reduced. With this anomaly, color recognition is established, but most shades cannot be distinguished.
- Dichromasia is characterized by the absence or cessation of functioning of one type of cone.
- Achromasia (achromatopsia or monochromasia) is diagnosed when a person is completely unable to distinguish between all three color spectrums. His vision is limited exclusively to black and white colors. A fairly rare deviation and is observed in only 0.2% of cases.
Types of color blindness
Dichromasia is divided into protanopia, deutranopia and tritanopia.
- Deuteranopia is the inability to distinguish between colors and shades of green.
- Tritanopia is the inability to see colors and shades of the blue spectrum.
- Protanopia is the lack of perception of colors and shades of the red spectrum.
Also in medical practice the concept of “abnormal trichomacy” is encountered. This name denotes a decrease, but not the absence, of the perception of a certain spectrum of colors, as was written about earlier, and the following deviations are distinguished:
- protanomaly, based on protanopia, impaired perception of red color;
- tritanomaly - blue;
- deuteranomaly - green.
Read the material on how to determine retinal detachment.
Abnormal trichomacy may be acquired.
Congenital color blindness cannot be treated and affects the patient’s life only in terms of choice of profession. This pathology does not entail any specific diseases, nor is disability established. The only exception may be the article monochromasia.
What is color blindness?
Experts identify four main types of this disease:
Human chameleon eyes + photo
- Abnormal trichromasia. It is the most common type of color blindness. A person perceives color shades, but sees colors that are not what they really are.
- Dichromasia. There is confusion with color perception because the eye can only distinguish certain shades. The essence of the pathology is that one of the primary colors completely disappears from color perception: blue, red or green. Congenital dichromasia does not cause inconvenience in everyday life, but acquired dichromasia will take some time to adapt to. There is a chance of recovery only if the pathology is acquired.
- Monochromacy. This type of color blindness affects only men, and the pathological process is inherited. Patients with monochromasia can only distinguish shades of blue. The patient does not see objects that are located at some distance from him. To recognize them, he has to peer and bring them closer.
- Achromasia. A person practically cannot distinguish colors. The brain is capable of recording only black and white colors, as well as their shades. Along with this, a person also develops other ophthalmological disorders. Sharp pain may bother you. Often patients see only the outlines of objects, and in order to read something, they need to wear glasses. Patients note that they see better in twilight light than in daylight. Treatment is aimed at reducing photophobia and improving visual acuity. Unfortunately, existing treatment methods are ineffective.
Drivers must take a color blindness test
Diagnostic methods
One of the most well-known methods for diagnosing color blindness remains Rabkin’s polychromatic tables, a test for color perception. The tables contain multi-colored circles of equal brightness. Various numbers and geometric shapes are made from circles of the same shade in the images. By the number and color of figures identified by a person, one can judge the degree and type of color blindness.
Rabkin table
You can also use the simpler tables of Stilling, Yustova and Ishihara. They were obtained by calculation and not by experiment. Doctors use the Holmgren method. According to it, it is necessary to sort skeins of multi-colored wool threads into three main colors.
And also about where you can cure retinal dystrophy here.
Diagnosis and treatment of color blindness
When diagnosing the type of color blindness, it is determined which color is recognized correctly, which one merges, and which one is not distinguished. The most famous method used in diagnosis is the Ishihara test, which is based on recognizing and correctly reading a number or letter shown on a folded color image.
Congenital color blindness is an incurable defect, but it can be corrected with the help of special optical means. There is also a special computer program designed to help people with this type of visual problem.
Monocular correction
In the case of monocular correction, the lens is always applied to the non-dominant eye. ChromaGen lenses are used in the same way as regular contact lenses. This method of correcting color perception deficiency was first tested by David Haris in England. In our country, this correction method is used minimally today. These contact lenses are made in shades of purple, pink, orange, yellow and green, in three different intensities.
When using it, it is important to take into account the subjective feelings of the person who, by viewing color samples, determines the intensity of the selected lens. Properly selected lenses will expand the color range and increase the expressiveness of individual colors. You should pay attention to the person’s personal feelings, especially in the case of protanomaly, since the wrong choice causes a tense state, the red color is perceived too brightly, and the person may refuse correction.
In the case of correction of color perception defects using contact lenses, it is important to know that these lenses are flat and, therefore, in the case of concomitant visual impairment, correction with refractive spectacle lenses is necessary.
Every tenth man is colorblind?
You ask: “Honey, how do you like my new coral dress?” and you get the answer: “Yes, great. Red suits you very well”? Don’t be upset: only 10% of men on the planet suffer from obvious color blindness, but almost every color blind man suffers from inadequate perception of individual colors, especially all shades of red. Blue can also be classified as a similar “complex” color – for some reason it is often seen as purple by men.
It is the fairer sex who are carriers of a defective gene that is passed on to men and makes them colorblind.
What color are apples?
Is everything okay with your color perception? Think about it, paradoxically, most of us don’t even realize that we are colorblind . Colorblind people learn about this feature completely by accident. Write in the comments what color the apples are in the picture. The author, for example, sees green and... lilac.
And finally. To check your color perception, we advise you to watch the following video. This is a fairly effective test for color blindness: if you do not see any differences between the right and left pictures, then you have every reason to go to a specialist (note: the right shows how color blind people see).
How do colorblind people see? – Video test for color blindness.
All the splendor of colors and colors in one video =>
Why is human color perception impaired?
The main cause of color blindness is genetics.
This is a congenital anomaly in which there is a lack of receptors sensitive to a certain color or a violation of their functions. The perception of color by a person depends on the level of the signal that comes from the cones, which are present in large numbers in the retina. People who are color blind perceive colors distorted due to a lack of cones with a certain pigment.
Causes of color vision disorder:
- genetic - people are born with peculiarities of color perception;
- injuries - disruption of the optic nerve can affect color perception;
- tumor processes and stroke also affect the correct perception of color;
- Taking certain medications can change the sensitivity of photoreceptors to color.
Normally, people's vision is trichromatic. Cones with the necessary pigments (green, red, blue) for color differentiation are available in the required quantity. By optically mixing primary colors, various shades are obtained. Colorblind people lack the necessary pigments, so they cannot correctly differentiate shades. Depending on what pigments are missing, it is customary to distinguish between three types of disorders.
Why are there no colorblind women?
Impaired functionality of the visual organs can be congenital or acquired. Acquired diseases arise due to mechanical damage, pathological changes, and brain injuries. Congenital color blindness occurs as a result of a genetic predisposition.
A woman suffers from color blindness only when two chromosomes are damaged. When one X chromosome is damaged, the second one compensates for the damage. When two are affected, color blindness develops. There are very few such cases. For this reason, girls practically do not encounter this pathology. It is worth noting that women can be carriers of pathology and pass it on to their children. The disease is not accompanied by other disorders in the body. Despite this, a person for this reason will not be able to develop in certain professions. Therefore, it is important to detect this pathology in a timely manner.
Etiology of color vision impairment
Color vision disorders can be acquired or congenital. A pathological change in color perception is often congenital , although it would be more correct to say that it is hereditary, transmitted through the male line . We will not find hereditary color vision disorders in women and girls, but color anomalies among males are quite common. This is due to the fact that hereditary transmission is ensured by genes transmitted in a recessive manner. Complete color blindness is very rare and usually accompanies severe pathology of the eyeball. Unfortunately, the reason why this anomaly occurs is still not clear.
It is easier to establish the cause when the color anomaly is acquired. Most often it is associated with various diseases of the retina, especially when the peripheral parts are affected. Naturally, these are not the cases when retinal detachment occurs - not only color blindness occurs there. Disorders of color perception in dystrophic diseases of the retina, as a rule, are characterized by a violation of the perception of three main components at once. Usually it all comes down to seeing everything around you in gray and white tones. In diseases of the brain, the perception of one of the three components at the central level is disrupted. This occurs due to a violation of color wavelength differentiation at the level of visual analyzers. The integrity and structure of the retina does not have any organic pathology.
