
What is dyschromatopsia?
27 May 2022
Dyschromatopsia is a disorder that prevents the correct perception of colors. Difficulty in recognizing the color chart may result in partial blindness to specific colors. In less common cases, no color may not be perceived at all.
Dyschromatopsia tends to affect males more than females, and is an eye disease that can be inherited (congenital) or acquired.
What differentiates dyschromatopsia from color blindness is that the former refers to any alteration in color vision, while color blindness is specifically a congenital dyschromatopsia.
Congenital dyschromatopsia compromises more the perception of red and green colors, while acquired dyschromatopsia affects the perception of blue, yellow, red and green. Also, congenital dyschromatopsia is not related to other visual defects, while acquired dyschromatopsia is.
Congenital dyschromatopsias can be classified as follows:
- Monochromatic: there is only one pigment in the macula and vision is reduced to a single color dimension.
- Dichromatic or bicolor: due to a change in one of the three basic color mechanisms.
- Trichromatic or trichromatic: all three types of color photoreceptors are present, but with a change in function. They are the most common and can seriously alter color perception.
The causes of acquired dyschromatopsias are many and, in general, in one disease there can be many types of alterations in color perception. The most common is macular degeneration, since the macula contains a large number of cells responsible for color perception, called cones.
There are several tests to detect dyschromatopsia, the most commonly used in ophthalmological consultations is the Color Perception Test, known as the Ishihara Test. It is based on showing the patient several plates with colors and numbers formed by a pattern of dots. The person who does not suffer from dyschromatopsia will be able to correctly appreciate the colors and numbers of each sheet shown. Those who suffer some kind of visual alteration in the perception of colors will perceive different numbers and colors.