Under Farbenfehlsichtigkeit ( dyschromatopsia, Dyschromasie ) refers to a defect in the retina, of which about eight to nine percent of the men, but only about one percent of women are affected. Sufferers have a defect in one of three color -promoting receptors in the eye. The exact type of color blindness can be determined in humans with a Farnsworth test or with a Anomaloscope. A simple qualitative method is to present the subject a pseudoisochromatische color chart Ishihara or Stilling Velhagen. This harmless for the person restriction on the color sense is not to be confused with the very rare color blindness.
Color blindness is genetic in most cases, that is innate. A fully color capable person has for the tags marriages three different receptors, called cones and therefore one of the trichromats (Greek τρίς "three" ). The three color receptors mediate the primary colors red, green and blue; the mixture of these receptor excitations gives the sensation color. For example, the resulting color is yellow in the brain by stimulating the receptors for red - green vision and vision (see color). In Farbenfehlsichtigkeit the function of at least one of these receptors is limited. A full function of color vision is referred to in the healthy as polychromasia.
Creatures with only one farbenvermittelndem receptor (red, green, blue or UV) are Monochromats (Greek μόνος "single" and χρῶμα " color" ). You can not perform any differentiable colors but only shades of gray.
Organisms with two types of cones for color perception are called dichromats (Greek δίο "two" ). Humans, in which a dye receptor is defective, and include:
- Protanopes lack the L cones (L for long / long wavelength light ). You have no way to process the on the L cones controlled sensory stimuli ( which are triggered by ingress of light / photons). Since the light that stimulates the L cones, mostly located in the red spectral region, it is called Rotblindheit. Is caused by a mutation of the opsin gene for the red cones only changed so that its absorption maximum is too close to the M-cones, one speaks of protanomaly.
- Deuteranopes lack the M-cones (M for medium / medium). These are the cones that respond primarily to light in the green color range. Therefore, the expression of green blindness. Is caused by a mutation, the absorption maximum of the green pin too close to that of the Rotzapfens, one speaks of deuteranomaly.
The above are collectively referred to as red-green color blindness. Protanope and deuteranope be as red or green blind called. A special case is the Blauzapfenmonochromasie in the red and green blindness is present simultaneously.
- Tritanopen lack the S-cones (S for short) or ( in German ), the K - pin ( K for short). Affected are blue blind. One speaks of blue-yellow color blindness. This is much rarer than the red / green color blindness.
Color defectives people are looking for the science of interest, as can be verified or falsified by their poor eyesight theories to see.