Adaptive strategies for reading with a forced retinal location.

Forcing normal-sighted participants to use a distinct parafoveal retinal location for reading, we studied which part of the visual field is best suited to take over functions of the fovea during early stages of macular degeneration (MD). A region to the right of fixation lead to best reading performance and most natural gaze behavior, whereas reading performance was severely impaired when a region to the left or below fixation had to be used. An analysis of the underlying oculomotor behavior revealed that practice effects were accompanied by a larger number of saccades in text direction and decreased fixation durations, whereas no adjustment of saccade amplitudes was observed. We provide an explanation for the observed performance differences at different retinal locations based on the interplay of attention and eye movements. Our findings have important implications for the development of training methods for MD patients targeted at reading, suggesting that it would be beneficial for MD patients to use a region to the right of their central scotoma.