Abnormalities of the electroretinogram and visual-evoked potential in vitamin E deficient rats

Flash electroretinograms, retinal oscillatory and cortical visual-evoked potentials were recorded in 10-month vitamin E deficient rats and in age-matched controls. A significant increase in the latency ( P < 0·0001) and decrease in amplitude ( P < 0·0001) of the electroretinogram a- and b-waves were observed in the vitamin E deficient rats compared with controls. The vitamin E deficient rats also showed a significant delay ( P < 0·002) in early oscillatory potentials. No significant group differences were obtained in the P1 latency or P1-N1 amplitude of the visual-evoked potential; however, the N1 peak was significantly delayed ( P = 0·01) in the vitamin E deficient rats. This study shows, for the first time, that the electroretinogram and visual-evoked potential to flash stimulation provide a sensitive index for monitoring the visual effects of vitamin E deficiency in the rat.