The Macular and Paramacular Subcomponents of the Pattern Evoked Response

Abstract

The studies to be presented have been carried out on healthy subjects, recording the pattern evoked response to a black and white reversing checkerboard stimulus, back-projected onto a circular translucent screen viewed monocularly by the subject at a distance of 1 meter. The full-field stimulus extends out from a central fixation point to an eccentricity of 16 degrees, and the individual checks subtend 50’. The pattern is reversed every 600 msec by moving it rapidly sideways through one square (10 msec transition time), and the response to 200 such reversals has been averaged in each run. For half-field stimulation, one side of the screen is masked off, and smaller areas of the remaining half-field stimulus could be masked off in the same way to test central or peripheral stimulation. The position of the central fixation light remains the same throughout.