A COMPARISON OF THE COMPONENTS OF THE MULTIFOCAL AND FULL-FIELD ERGS

The multi-input technique of Sutter and Tran (1992) yields multiple fo cal ERGs. The purpose here was to compare the components of this multi focal ERG to the components of the standard, full-field ERG. To record multifocal ERGs, an array of 103 hexagons was displayed on a monitor. Full-field (Ganzfeld) ERGs were elicited by flashes presented upon st eady background fields. The latencies of two prominent subcomponents o f the full-field ERG were altered by varying the intensity of the incr emental flash or the intensity of the background field. By showing tha t similar manipulations of the multi-input parameters produce similar changes in latency, we were able to relate the components of the multi focal ERG to the components of the full field ERG. The biphasic respon ses of the multifocal ERG appear to be generated by the same cells gen erating the a-wave and positive peaks of the full-field cone ERG.