[ ˌprəʊtə'nəʊpɪə ]
■ noun colour blindness resulting from insensitivity to red light, causing confusion of greens, reds, and yellows. Compare with deuteranopia , tritanopia .
Origin
early 20th cent.: from proto- 'original' (red being regarded as the first component of colour vision) + an- 1 + -opia .