Area-luminance relationship for a constant light peak of the standing potential in the human eye

The area-luminance relationship of the light peak of the slow oscillation of the standing potential was investigated in man by determining luminance response curves for field sizes between 5 degrees and Ganzfeld after dark adaptation and at two levels of adaptive illumination. The luminance necessary for a low constant light peak was read therefrom and related to the area stimulated. With foveally and extrafoveally centered test lights a straight line with gradient -1 was found if the logarithm of the threshold luminance was plotted against the log area of the field. This indicates that the threshold of the light peak of the standing potential is inversely proportional to its area.