Color matches of patients with retinitis pigmentosa.

The color matches of 46 retinitis pigmentosa (RP) patients were found to differ significantly from those of 55 unaffected observers. The color matches of group I (trichromatic) RP observers were more protanomalous (i.e., required a greater red/green mixture ratio) than those of unaffected observers. The matches of group II (dichromatic) RP observers were more protanopic (i.e., required less yellow to match the red primary) than those of the group II unaffected observers. In view of current evidence, this difference can be attributed to reductions in the pigment optical density of cone photoreceptors in eyes of RP patients.