Pattern visual evoked cortical potential measurement of luminance threshold in retinitis pigmentosa.

We measured the luminance threshold in eight patient (12 eyes) with retinitis pigmentosa using pattern reversal visual evoked cortical potentials (PVECPs). With decreasing pattern luminance (0 to 3.0 log unit neutral density filters), the amplitude of the p 100 component decreased linearly. Luminance threshold was determined by extrapolating the regression line of amplitude as a function of luminance to 0 microV. Our results showed that luminance threshold measured by PVECP was approximately 1.2 log units higher in patients with retinitis pigmentosa than in age-matched normal controls. Thus the PVECP may provide a way of quantitatively evaluating central retinal visual function in patients with retinitis pigmentosa.