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Jonathan Patrick, Neil Roach, Paul McGraw; Temporal modulations enhance spatial resolution for dynamic stimuli. Journal of Vision 2016;16(12):1126. doi: https://doi.org/10.1167/16.12.1126.
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© ARVO (1962-2015); The Authors (2016-present)
The loss of central vision experienced by patients with age-related macular degeneration (ARMD) means they must rely on peripheral vision, which is limited in its spatial resolution capacity. Here we investigate stimulus manipulations intended to improve resolution for dynamic targets. Resolution thresholds were measured using a monocular four-alternative orientation discrimination task with Landolt rings presented at 10deg eccentricity. Two types of image motion were investigated along with two different forms of temporal manipulation. Ocular motion was simulated by jittering target location using previously recorded fixational eye movement data, amplified by a variable gain factor (0 to 8). Object motion was generated by translating a target along an isoeccentric path at a constant speed (0-20deg/s). In one stimulus manipulation, the sequence was temporally subsampled by displaying the target on a total of five evenly spaced video frames in the 25-frame sequence. In the other manipulation, the contrast polarity of the stimulus was reversed from white to black after every five video frames. With simulated ocular motion, we found that resolution thresholds were consistently improved by contrast polarity reversal but impaired by temporal subsampling. Resolution thresholds with object motion were again improved at all speeds by reversing contrast polarity, while temporal subsampling was found to improve resolution thresholds at high speeds but degrade performance for low speeds. These results suggest that contrast polarity reversal and temporal subsampling produce differential effects on spatial resolution under different types of retinal motion. Applying contrast polarity reversal to peripheral scenes may have the potential to improve visual performance for those with a loss of foveal visual function.
Meeting abstract presented at VSS 2016
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