[Multi-focal electroretinograms in normal subjects].

The multi-focal electroretinogram (multi-focal ERG), developed by Sutter (1992), is a method of recording the spatial distribution of focal ERG in a short time using multi-input stimulation. Using this technique, we can detect the spatial extent and severity of damage to the macula. In this study, we recorded multi-focal ERGs from 20 eyes of 20 normal subjects and analyzed the topographical property of responses. In every subject, a negative wave followed by a positive wave could be recorded and we named them the N1-wave and the P1-wave, respectively. The amplitudes of the N1-wave and the P1-wave were the largest in the fovea and they became smaller with eccentricity. In P1-wave amplitude, the greatest inter-subject variability was observed at the fovea. The N1 and P1 latencies were shorter in the upper retina than in the lower retina. The amplitude was larger in the upper retina than in the lower retina, which suggests functional superiority of the upper retina. There was no statistical difference of latency and amplitude between nasal and temporal retina. We found no statistical difference between the responses of the papillomacular bundle and those of the temporal retinal area. The mapping obtained by multi-focal ERG was useful as objective perimetry.