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Types

Dichromacy

A dichromat has only two populations of cone cells. Typically, either the red or green population is absent in their retinas. There are three types of dichromacy: protanopia (red is absent), deuteranopia (green is absent), and tritanopia (blue is absent).


In protanopia, also called "red weakness," the cone cells sensitive to red light are absent. A protanope is able to see blue, short wavelengths, but as light waves approach green in the spectrum, the perception b...Read the full article