[ ˌtrɪtə'nəʊpɪə ]
■ noun a rare form of colour blindness resulting from insensitivity to blue light, causing confusion of greens and blues. Compare with protanopia , deuteranopia .
Origin
early 20th cent.: from Gk tritos 'third' (referring to blue as the third colour in the spectrum) + an- 1 + -opia .