Abstract
Purpose :
People with central vision loss (e.g. macular degeneration) often adopt eccentric retina locations outside the affected macular region for fixation (pseudo fovea or Preferred Retina Locus, PRL). Despite its significant role in visual function, the mechanism underlying the emergence of PRL still remains unclear. Here, we developed a novel training paradigm that can effectively induce a PRL at any intended retina location by integrating oculomotor control and pattern recognition training. We proposed it as a model system to study the nature of PRL development and its impacts on various aspects of visual function.
Methods :
A simulated central scotoma (12° in diameter) was induced in eight normally-sighted subjects through a gaze-contingent display. A subject’s entire peripheral visual field was blurred, except for a small circular aperture (5° in diameter) with a location randomly assigned to each subject (to the left, right, above, or below the scotoma). Under this viewing condition, subjects performed a highly demanding oculomotor and pattern recognition task. Changes in various aspects of visual function were also evaluated before and after training at PRL and non-PRL locations.
Results :
After 6−10 hours of the training, all subjects formed their PRL within their clear window (training location). We also found significant improvements in the precision of oculomotor control (ps<0.01) and pattern recognition performance (>=19%, ps<0.01) over the course of the training. Furthermore, there were significant improvements in some untrained tasks (>=18%, ps<=0.04) such as crowded letter recognition, reading, and spatial attention at PRL location, suggesting transfer of learning to untrained stimuli and tasks.
Conclusions :
Our results demonstrated that, within a relatively short time period, a stable PRL could be induced at any intended retina location in normally-sighted subjects with a simulated central scotoma. Furthermore, our oculomotor and perceptual training appeared to improve high-level visual function such as letter recognition, reading, and attention. Our findings suggest that our integrative training paradigm may serve not only as a model system to study the dynamic nature of the PRL formation, but also as a viable rehabilitative regimen for individuals with central vision loss.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.