S-cone electroretinogram to Ganzfeld stimuli in patients with retinitis pigmentosa

Cone electroretinograms (ERGs) elicited by different chromatic stimuli were recorded from patients with typical retinitis pigmentosa (RP) younger than 50 years of age. Ganzfeld color flashes on a bright white background illum ination were used to elicit short-wavelength-sensitive (S-), and mixed long - (L-) and middle- (M-) wavelength-sensitive cone ERGs. Three patients with dominant inheritance, 22 patients with non-dominant inheritance, and 27 ag e-similar normal subjects were compared. Although the b-wave amplitudes of both the S- and L,M-cone ERGs were reduced in the RP patients, the S-cones were reduced to a greater degree than the L,M-cones. No significant differe nce in the S-cone reduction was observed between patients with dominant inh eritance and those with non-dominant inheritance. The selective reduction o f the S-cone system, reported previously in psychophysical studies, may be attributable not only to the macular region but also to the entire retina.