Redgreenhäiriöt

Redgreenhäiriöt are a set of color vision deficiencies characterized by difficulty distinguishing red and green hues. They arise from alterations in the cone photoreceptors that detect long (red) and middle (green) wavelengths of light, affecting how red and green are perceived.

There are two main groups. Dichromacy, where one type of cone is missing or nonfunctional, includes protanopia (lost L-cones) and deuteranopia (lost M-cones). Anomalous trichromacy, where one cone type functions abnormally, includes protanomaly (altered L-cones) and deuteranomaly (altered M-cones). People with these conditions may still see a range of colors but have reduced ability to separate red from green, especially in subtle or complex color scenes. Blue-yellow color vision and other rare variations are separate categories and less common.

Genetically, redgreenhäiriöt are typically inherited as X‑linked traits, meaning they occur more often in males and may be noticed from birth or early childhood. About several percent of people of certain populations have a red-green deficiency, with higher prevalence among men of Northern European descent.

Diagnosis is usually made through color vision tests conducted by eye care professionals. Common tools include Ishihara color plates and, in some cases, an anomaloscope to measure color-matching abilities. Genetic testing may be used in research or specialized clinics.

There is no cure to restore typical color vision. Coping strategies focus on practical adaptations: relying on labels, patterns, and brightness cues; using high-contrast designs; and employing color-identification apps or assistive lenses that can improve color discrimination in some situations. Public and educational materials are increasingly designed to be accessible to redgreenhäiriöt, reducing reliance on color alone for information.