Visual Recovery Following Local Adaptation of the Peripheral Retina (Troxler's Effect)

Abstract

The course of recovery has been determined for two observers during the first five minutes after the removal of a bright extra-foveal stimulus, which had been made to disappear by steady fixation. The recovery curves show two linear portions when plotted on a log-time basis, the earlier portion having the steeper slope. The effects of testing different zones within the locally adapted area, of changing the size of test stimulus, of changing the luminance and the size of the conditioning field, of changing the degree of fixation, and of changing the retinal region have all been investigated. Results indicate that the early (rapid) phase of recovery represents recovery from Troxler's Effect, while the later (slower) phase represents recovery from normal light adaptation. The novel effects found are shown to be in accord with certain phenomena noticed by previous investigators, and are consistent with a boundary neutralization model for the visual organization of Troxler's Effect.