When their scotoma is lost, patients with central vision loss frequently choose a site outside of it as their new preferred retinal locus (PRL). In addition to being crucial for the rehabilitation of patients with central vision loss, the development of a PRL also advances the knowledge of how the brain adjusts to the absence of visual information.
Many researchers investigated the issue using a gaze-contingent display paradigm, imposing an artificial scotoma to simulate central vision loss in subjects who were otherwise sighted, with the crucial premise that the “PRL” thereby developed is the result of visuomotor adaptation, as is the case for individuals with a real scotoma. The accuracy of the presumption was examined in the study. In order to construct a “PRL” for saccade eye movements, they first trained normally sighted participants using a gaze-contingent display and an artificial scotoma. Then, when the artificial scotoma was arbitrarily switched on or off, they contrasted the characteristics of saccades.
Subjects automatically switched to utilize their fovea with a shorter saccade delay when the fake scotoma was removed. According to the research, the emergence of a “PRL” in response to a synthetic scotoma can be a tactic rather than a true visuomotor adaptation.
Reference: jov.arvojournals.org/article.aspx?articleid=2783665
