Electroretinographic studies of families with dominant retinitis pigmentosa.

Full-field electroretinograms were recorded from four different families with dominant retinitis pigmentosa. Two different types of the disease were recognizable and consistent within each pedigree, one with normal cone b-wave implicit times (one pedigree) and the other with prolonged cone b-wave implicit times (three pedigrees). The cone b-wave amplitude was found to decrease with age, but the implicit time did not, suggesting that the amplitude is useful for monitoring the progression of the disease whereas the implicit time seems more suitable for distinguishing different types of the disease. The progression rate was analyzed in a large pedigree, spanning six generations, three of which were examined in detail. The recently described Pro23His gene was not detected in the families.