achromate

Alternative form of achromat (“type of lens”).

Each achromate consists of a quartz and a fluorite lens mounted in a common frame.

Alternative form of achromat (“color-blind person”).

An achromate, as affected individuals are known, must rely on the rods, the photoreceptors responsible for vision at night and in low-light situations, for vision at all times.

Funny you should mention colours... I'm an achromate from birth.