Experimental alteration of the red cone photoreceptor process

In our experiments, intense monochromatic coherent light (647.1nm) was used to permanently alter the red cone process. As the turtle (Pseudemys) is very sensitive in the red region of the spectrum, it was chosen as an appropriate animal model in which to study initially experimentally induced protanopia. Dark adaptation and spectral sensitivity functions were measured for ERG criteria using a vector voltmeter. Successive dark adaptation functions were measured for chromatic light adaptation levels from full bleach to about two log units above full bleach, where the dark adaptation was abruptly altered in its dynamic range by about one log unit. Pre- and post-exposure measurements showed the action spectra suppressed in sensitivity by about one log unit from 600 to 660 nm. A small depression in the short wavelength region (420-500nm) was also observed.