Abstract

We simultaneously recorded PERG and VECP responses from the visual periphery generated by an alternating checkerboard (0.3 checks, 89% contrast) under both steady state and transient conditions. Subjects viewed the stimulus through trial lenses of varying powers. The best-fit straight lines through the right sides of the amplitude versus dioptric-error plots had a slope of about 0.15 V/diopter for both the PERG and the VECP. These slopes can be compared to data from the center,¹ where the PERG slope had about the same fall-off rate, but where the VECP slope was much greater at about 2.0 V/diopter. Thus, we find that the peripheral VECP is much less sensitive to blur than is the central VECP. This is consistent with results from psychophysical acuity experiments. When a stimulus to the fovea is blurred, acuity decreases very rapidly. On the other hand, in the periphery it does not matter whether refractive error is present or nob acuity is the same.² This peripheral insensitivity to blur is now shown in the VECP.

© 1990 Optical Society of America