Origin of color blindness
1844, replacing Daltonism (after English chemist John Dalton, 1766-1844, who published a description of it in 1794); in figurative use, with reference to race or ethnicity, attested from 1866, American English. Related: color blind (adj.).
A defect in perception of colors, caused by a deficiency of certain specialized cells in the retina that are sensitive to different colors. The condition may be partial (as in “red-green colorblindness,” in which a person cannot distinguish red from green), or complete (in which the person sees all colors as gray).