Dichromacy
Dichromacy is a severe colour vision defect. The cause is that he three basic colour mechanisms is absent or not
functioning. It is hereditary mostly affects boys. Dichromacy happens when one of the
cone pigments is missing and colour is reduced to two dimensions.
There are 3 types of Dichromacy, Protanopia, Deuteranopia and Tritanopia.
functioning. It is hereditary mostly affects boys. Dichromacy happens when one of the
cone pigments is missing and colour is reduced to two dimensions.
There are 3 types of Dichromacy, Protanopia, Deuteranopia and Tritanopia.
- Protanopia is caused by the complete absence of red retinal photoreceptors. They can only see light wavelengths from 400 to 650nm, instead of the average 700nm. Reds are seen as blacks, purple cant be distinguished from blue and all orange-yellow-green shades that are too bright to stimulate the blue receptors appear as a similar yellow hue. It is hereditary and present in 1% of males.
- Deuteranopia is where the green retinal photoreceptors are gone, and it affects the ability to distinguish red and green. There are only two cone pigments in their eyes. It's hereditary and sex-linked.
- Tritanopia is an extremely rare colour vision defect where there are only two cone pigments present and no blue retinal receptors. Blues look green, yellows and oranges look pink, and purple looks deep red. It is related to Chromosome "7"