Many people know that the human eye can distinguish from one another three primary colors – blue, green and red – and their many combinations. But most other representatives of the animal world either do not see the difference between colors at all, or are able to distinguish from each other only those colors that are necessary for their survival. For example, horses can only distinguish shades of brown from all colors, since this vision allows them to separate green from dead grass.
Color blindness is color blindness, that is, the lack of the ability to highlight any one of the primary colors, two of them, or all three. The term color blindness comes from the name of the Englishman – Dalton – who suffered from the disorder of the selection of shades of red from the mass, who was able to describe this pathological phenomenon.
Color blindness is a characteristic of vision that a person acquires from birth. The phenomenon is caused by the X chromosome and, as a rule, is transmitted at the genetic level from mother to male child. For this reason, color blindness often pursues the stronger sex. People with color blindness are unable to distinguish between the three colors – green, blue and red.
However, color vision disorders that a person acquires on the path of life can also be observed. The causes of such disorders can be diseases of the eye retina, damage to the nerves of vision or visual centers in the central nervous system. Color blindness of acquired origin can be noted in one eye or in both, and is usually characterized by a disorder in the selection of all primary colors at once. With such a disease, a color blind person can see everything around him only in blue, red or green. When the underlying pathology is cured, color blindness is also cured, and a person’s vision returns to normal.
How color blind people see, or what happens in the human body with a color recognition disorder
As many people know, the human eye is a device for collecting and refracting light rays that emanate from various objects in a person’s environment. Refracted rays focus on the retina, which in turn is a complex of receptors responsible for receiving information. The retina of the human eye is composed of rods and cones. These rods and cones transport the information received by the retina to the nerves of vision, which transmit the data to the brain.
The cones, which can be of three varieties, are “in charge” of color perception. The types of cones are determined by the presence of pigment in them, which is responsible for the perception of only blue, only green or only red. People with all three types of cones have normal color perception.
Types of color blindness
How color blind people see is determined by the type of color blindness.
The first type of color blindness is called trichromasia , when a color blind person sees all colors – blue, red and green – but in a weakened form.
The second type of color blindness is called dichromasia , when a color blind person sees any two colors, except for the third. This type of color blindness is more severe than the first type. In the absence of the ability to see red, protanopia occurs , in the inability to see green, deuteranopia , and in the absence of blue, tritanopia .
The last type of color blindness is called monochromaticity , in which there is a complete lack of color perception, complete color blindness. In other words, a person suffering from monochromaticity is able to see the world around him only in black and white.
The most common type of color blindness is trichromasia , the presence of which is established only after a series of studies.