Abstract
Individuals with healthy vision can spontaneously form a stable preferred retinal locus (PRL) over a period of several hours during eccentric viewing tasks. This process is poorly understood and does not appear to be driven by selection of retinal regions that optimize performance. It is also unknown whether PRL formation can be guided by training or attention, or whether the initial process of PRL formation speeds or retards subsequent PRL reformation. Addressing these questions may help individuals with central visual field loss by informing a training program that promotes PRL development in high utility regions and supports PRL retraining in response to disease progression or remediation. In this experiment, four individuals with normal or corrected-to-normal vision were given two, one-hour blocks of eccentric viewing training separated by a week. Their task was to guide a gaze contingent ring over a stable fixation target. The ring's position was oriented 4 degrees either to the right or below their foveal point of regard (POR). Between blocks, the ring's orientation was switched. To prevent foveation, the target was removed if it fell within 2.5 degrees of the fovea. The ring contracted as the subject maintained the ring on-target and expanded as it fell off-target; their task was to "make the ring as small as possible." Task performance was measured in degrees of error between the ring's center and the target's center. All subjects' performance curves fit roughly exponential decay functions between both trials and blocks. Training in the first block also significantly enhanced performance in the second. Finally, significant idiosyncratic effects of orientation on performance were observed. These results suggest that PRL training may be possible (at least among individuals with healthy vision) and that training effects transfer to new PRLs and enhance performance on this task even after significant PRL orientation shifts.
Meeting abstract presented at VSS 2015