the.com/color blindness

means A visual condition where certain colors (most often reds and greens) look similar or indistinguishable because some of the eye's color-detecting cone cells don't work as expected.

from Straightforwardly descriptive — pairing 'color,' from Latin color, with 'blindness,' from Old English blind, used since the word for the condition entered English in the 1800s to describe an inability to perceive certain colors, not a loss of sight itself. The condition got scientific attention after chemist John Dalton, who had it himself, published a detailed account of his own red-green confusion in 1794 — which is why it was long nicknamed 'Daltonism' in several languages.