Pattern electroretinograms recorded with a skin electrode in pigmentary retinal degeneration

In 24 patients suffering from pigmentary retinal degeneration the electroretinograms to pattern stimulation (PERG) were recorded with a silver-cup electrode placed on the center of the lower eyelid skin referred to an electrode on the earlobe. The results were compared with the responses to flash stimulation (FERG) and pattern visual evoked cortical potentials. None of patients showed normal FERGs. Nineteen of 48 eyes showed subnormal FERGs. The PERG was recorded from those 19 eyes. In the remaining 29 eyes with flat FERG, 8 eyes showed clear PERGs. The peak latency of the first positive component of PERGs was found to be prolonged in these patients. PERGs seemed to be recordable in the patients whose visual acuity and central visual field were relatively well preserved.