Imagining colors that we have never seen (or that our eyes cannot directly perceive) is an impossible task. And yet, not all people are capable of seeing the same colors: those who distinguish less than most are color blind.
Color blindness is a relatively common condition in men (affects around 8%) and rarer in women (around 0.5%). Although it is generally considered that it does not negatively affect daily life, the truth is that it can be an impediment to the exercise of various professions and can even prevent the correct reading of traffic lights.
What is color blindness and what are its causes?
Color blindness is a genetic disorder that affects the ability to distinguish colors. It occurs in highly variable degrees in a person, ranging from slight distortion to the inability to distinguish any color (achromatopsia).
This modification affects the genes responsible for producing cone pigments, a type of sensory cell that we have in the retina. There are three types of cones: those sensitive to red color, those sensitive to green and those sensitive to blue. When one (or several) of the types does not produce pigment due to color blindness, the affected person loses the ability to distinguish that or those primary colors and the secondary colors that are formed from them.
Specifically, it is transmitted by a recessive allele linked to the X chromosome (one of those that make up the pair that determines chromosomal sex). If a male inherits an altered X chromosome, he will be color blind; For her part, a woman will only be color blind if she has both chromosomes altered. This is why it is much more common in men.
Today, color blindness has no cure or possible treatment, although there are glasses that can help distinguish diffuse colors in some people. In addition, some researchers trust the potential of gene therapy to solve this condition in the future, although it is still a very distant reality.
How do color blind people see?
The vision of color blind people will depend on the cells affected. Thus, there are several types of color blindness.
On the one hand, there are the achromatic color blind , that is, those who do not have functional cones of any kind. These people cannot perceive color, but see in black and white.
On the other, those who have two types of cones or monochromatic altered . In this case, only one color is perceived, so the color takes on a single dimension.
Color blindness, which consists of the alteration of a single type of cone, or dichromatic, for its part, is divided into three types, depending on the absent or dysfunctional retinal receptor: deuteranopia , when the retinal photoreceptors of the green color are missing; protanopia , when red photoreceptors are absent, or tritanopia , the less common type, when blue ones are absent .
In these variables, people have difficulties to distinguish the color in question, as well as the color ranges that include it.
These are just simulations of how people with color blindness view. However, it is impossible to accurately show the perception of another person , due to the processing of the stimuli carried out by the brain of each person.