A preferred retinal location of fixation can be induced when systematic stimulus relocations are applied.

Abstract

Patients with central vision loss obtain visual information by fixating on an object eccentrically with a preferred retinal locus of fixation (PRL). Patients do not always choose the most efficient PRL position, and as a consequence, visual performance is not always fully exploited. This study investigates whether PRLs can be induced by applying systematic stimulus relocations. The PRL was trained using a central scotoma simulation in 15 healthy subjects. They performed different visual tasks during four sessions, after which their reading performance was evaluated. In five subjects the stimulus was relocated to the left hemifield whenever a saccade would place the stimulus on the opposite hemifield. In five different subjects the relocation was inversed: The stimulus was located in the right hemifield. The relocation was 7.5° of visual angle and it was applied horizontally. Five additional subjects naturally chose the PRL location. They were used as the control group to evaluate the development of a PRL. After training, subjects performed visual search tasks on static stimuli. Evaluation after training showed that systematic stimulus relocations can be used to influence the development of the PRL. These results might be significant for the development of training strategies for the visually impaired.