Red-Green Color Vision, Defects

Synonyms

Achromatopsia

Definition

Dyschromatopsia is a congenital or acquired disorder of color vision. The human retina has three types of cones, each optimally responding to one of the primary colors: blue-sensitive cones (coded on chromosome 7), red-sensitive cones, and green-sensitive cones (both coded on the X-chromosome). The different colors of the spectrum are perceived by different mixtures of these three colors. Normal individuals are called trichromats (three-color system). In contrast, dichromats have only two functioning cone types, and monochromats only have one. The term “protanopia” refers to a defect in red perception, whereas “deuteranopia” is a defect in green perception and “tritanopia” is a defect in blue perception (Barrett et al. 2012).

Etiology

Mutations in the genes coding for the cones can cause congenital color blindness. The most common mutations occur in the X-chromosome and thus affect males much more commonly than females (see “Epidemiology”).

Color...