Synonyms in a broader sense
Medical: Achromatopsia, Achromasia
Introduction
With total color blindness, no colors at all can be perceived, only contrasts (i.e. light or dark). Often red-green blindness is also erroneously called color blindness, although it is a color blindness (color anomaly). A distinction is made between two forms: congenital color blindness and acquired color blindness.
Epidemiology
1 to 2 persons per 100,000 are color blind. Total color blindness is therefore very rare. Women and men are affected about equally often. In Germany there are currently about 3000 people living with this disease.
Causes of color blindness
The retina of the eye in healthy individuals consists of light-dark receptors (rods) and color receptors (cones), of which there are three types: In interaction, the three types of cones convey the different color impressions. If someone is color-blind, either all types of cones are missing or they are all non-functional, which is why the person concerned can no longer perceive colors but sees the world in black, white and gray. Color blindness can be congenital or acquired.
More common is the congenital form, which is inherited autosomal-recessively. Autosomal means that the disorder is not located on a gene of the sex chromosomes, which is why no sex is preferentially affected. Recessive means that there must be two defective copies of the gene, i.e. mother and father must pass on a “sick” gene to their child in order for the disease to break out (color-blind).
To date, four genes are known to be responsible for about 80% of color blindness. There is also the acquired form of color blindness, where the cause is not in the eye itself, but in the processing of the signal “color” to the brain. It can be caused, for example, by a stroke, craniocerebral trauma and other brain injuries. It can be reversible, but it can often persist and usually poses a greater problem for those affected in everyday life than for those with congenital color blindness, as this involves a major adjustment.
- Those that have red
- The blue and
- Absorb the green light.
All articles in this series:
