Multifocal ERG reveals long distance effects of a local bleach in the retina

AbstractTo examine the distribution of ERG-activity in the central visual field after local bleaching of the fovea, multifocal electroretinograms were recorded in eight normal volunteers before, during and after recurrent light exposure. During bleaching (90% bleached pigment), the response density (scalar product) of the foveal area (0–2° eccentricity) decreased from 10.7±3.5 to 4.1±1.9 nV/degree2 (P<0.001). The average activity in the extrafoveal macular area was unchanged, while the amplitudes were frequently (in 53 of 54 areas) enhanced at 5–30.5° eccentricity. Here the average response density changed from 3.1±0.9 to 3.5±1.0 nV/degree2 (P