The commonest form of colour blindness, in which someone cannot see the difference between red and green. Also called protanopia [Described 1794. After John Dalton (1766-1844), English chemist and physician. Founder of the atomic theory, he himself was colour-blind.]
Sex-linked, inherited form of color blindness characterized by inability to distinguish red from green.
A defect in color vision in which a person cannot distinguish between reds and greens. The term has been used to refer to color blindness in general.