Detection of the electroretinogram in retinitis pigmentosa

An electronic summating technique has been used to detect low amplitude electroretinograms in advanced cases of retinitis pigmentosa. The electroretinogram was obtained with subjects who could not deteot visual stimuli unless they were within three degrees of fixation. The log sensitivity of the electroretinograms of twelve patients of differing deficit was found to have an approximately linear relation to the log area of intact retina. Evoked occipital potentials were also obtained. The significance of these complicated potentials is discussed.