Temporal modulation sensitivities of red- and green-sensitive cone systems in dichromats.

The temporal modulation sensitivities of protanopes, deuteranopes and normal observers were measured with sinusoidal grating patterns (of spatial frequency 2.5 c/deg) whose contrast was modulated sinusoidally in time. Contrast sensitivity functions obtained from the three types of observers are almost identical. If we accept that in each class of dichromat only one cone type (red-sensitive, R, or green-sensitive, G) supports threshold, and that post-receptoral filters in both classes of observers are the same, the results show that R and G cones have the same temporal properties.