Colorblindness-Tritanopia

A selective deficiency in blue (short wavelength) spectral sensitivity is characteristic of this disorder.  Most patients retain the ability to see red and green colors although several patients with both defects have been reported.  It seems to be a stable disorder with no evidence of progressive retinal dysfunction.  ERG responses of long wavelength-sensitive cones are normal whereas those of blue-sensitive cones are undetectable.  This selectivity distinguishes tritanopia from acquired forms of color blindness such as macular disease and rod-cone dystrophies in which there is generalized dysfunction among cones.  However, there is wide variability in responses based on color vision testing suggesting that rudiments of blue-sensitive opsin function remain in some patients.