Color blindness is one of the better-known visual impairments. This is probably because it is relatively easy to understand, and one can imagine the situation of those affected quite well: color-blind is whoever sees the world like a black-and-white movie.
But is that really the case? And why does color blindness exist at all?
To understand why some people are color-blind, one first has to comprehend how all other people see colors at all. In our eye there are two types of receptors, i.e. parts of the eye that react to external influences – in vision, the external influence is light. The ones called rods react to differences between light and dark in general. The others, called cones, exist in three different versions. There are cones that react to green, to red, and to blue light.
There are people in whom the cones do not work at all. But that is very rare. When people colloquially talk about color blindness, they often mean all disorders of color vision, i.e. disorders that prevent or restrict those affected from seeing colors. The most common of these disorders, and the one that doctors here at Augenland Frankfurt most often deal with, is red-green weakness. In those affected, either the red cones, or – more often – the green cones do not function. Roughly 5% of the population are affected, in nine out of ten cases men. This is because the weakness is genetic: the genes for the red cones and the green cones are located on the X chromosome. Men have only one, but women have two. Because if the gene is damaged on one chromosome, the other chromosome can compensate, women are far less often affected than men.
At the same time, this is the reason why a blue weakness is so much rarer than a red-green weakness. Because the genes for the blue cone lie on another chromosome, of which both men and women have two. That both are damaged at the same time is very rare. That the red and green cones do not function at the same time is even rarer. In all of Germany, there are only about 3,000 people who cannot see any colors at all.
These people, however, are severely limited by this. On the one hand, our everyday life is strongly shaped by colored symbols, such as traffic lights. In addition, these people, since their cones do not function, rely only on their rods, and these are less densely distributed across the retina than the cones. People who are completely color-blind therefore not only see no colors, but also extremely blurry. In addition, their eyes are not very adaptable to different lighting conditions, and they become quickly dazzled. Tinted glasses can compensate for such problems to a certain degree, but the visual defect is not curable. Unlike red-green weakness, men and women are equally often affected.
Men and women are also equally often affected by a pure blue weakness. However, it is much rarer than red-green weakness, since it, like complete color blindness, would have to be caused by a defect occurring by chance on both chromosomes at the same time. Unlike complete color blindness or red-green weakness.
If you suspect that you or your child might be affected by a color vision disorder, we will be happy to arrange an appointment for an examination with you. While there are self-tests with which one can check whether one’s color vision is impaired, to clarify whether this significantly affects your daily life, for example when driving, a medical examination is necessary – one that we offer here at Augenland.
By the way, Augenland Frankfurt also routinely carries out examinations of color vision as part of certain assessments. For both the driving license assessment and the assessment for people who want to operate a motorboat, an examination of color vision, alongside other aspects such as visual acuity and spatial vision, is prescribed. Augenland Frankfurt will gladly arrange an appointment with you and issue you such an assessment.
Conveniently book an appointment online at your Augenland Frankfurt.