Tritanopic color matches and the middle- and long-wavelength-sensitive cone spectral sensitivities

Tritanopic color matches (i.e. matches that depend on the middle- (M) and long- (L), but not short- (S) wavelength-sensitive cones) were made between two half-fields: one illuminated by either a 405 or a 436 nm Hg spectral line; the other by a light of variable wavelength and radiance. Our purpose was to test between rival M- and L-cone spectral sensitivities, which should predict the tritanopic matches. The observers were tritanopes, in whom functioning S-cones are lacking, or normal trichromats, in whom artificial tritanopia was induced by a strong, violet adapting field. The wavelengths found to match the 405 and 436 nm lights agreed poorly with those predicted by the cone spectral sensitivities of Smith and Pokorny (1975) [Vision Research, 15, 161], while the 405 nm matching wavelength agreed poorly with that predicted by Stockman, MacLeod and Johnson (1993) [Journal of the Optical Society of America, A10, 2491]. Both matching wavelengths agreed well, however, with the predictions of the Stockman and Sharpe (2000) [Vision Research] M- and L-cone spectral sensitivities, which lie within the range of measured matches.