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R. Zhou, A. Johnson, R. Gurnsey, M. von Grünau; Eye movement strategies: A comparison between individuals with normal vision and simulated scotomas. Journal of Vision 2008;8(6):640. doi: https://doi.org/10.1167/8.6.640.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: Central visual field deficits (i.e., macular degeneration, MD) can impair individuals' visual performance. Individuals might use alternative eye movement (EM) strategies to compensate the deficiency, e.g. by making use of the unaffected periphery. Furthermore, visual tasks for those individuals would be effortful, that is, they would need to increase EM frequencies and durations to make accurate responses. Method: We presented computer-generated (MATLAB) images either with or without simulated scotomas to normally sighted individuals. Scotoma properties were varied to correspond to different stages of MD. We recorded EM (EyeLink II eye tracker) when observers were making target discrimination tasks. Data were collected for fixations, X and Y positions of EM, and behavioral responses such as accuracy and reaction time (RT) in a 3D texture discrimination task. Results: Fixation durations and variability were bigger for simulated MD. Number of fixations was also higher for MD. Mean X and Y positions were similar for control and MD, but they were more variable for MD. Behaviorally, RTs were longer and more variable for MD and more errors occurred. Conclusion: Central visual field loss impaired visual performance. Visual tasks could still be performed, but EM parameters and temporal and spatial EM patterns needed to be adjusted. This suggests that specific visual aids and training programs could be designed by incorporating residual visual functions (i.e., peripheral visual field) during dynamic scene perception.
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