Showing papers by "Clifton M. Schor published in 2010"
TL;DR: A pulse-step model of accommodation and convergence was constructed and supports cross-coupling of both the pulse and step components and simulates the primary empirical findings that: (1) disparity vergence has a higher main sequence slope than accommodative vergence, and (2) both accommodative and disparity acceleration increase with response amplitude whereas accommodation acceleration does not.
32 citations
TL;DR: This work designed a novel stimulus that uses perisaccadic spatial distortion to generate inconsistency between headcentric and retinal disparity, and is the first demonstration that a coding scheme other than Retinal disparity has a role in human stereopsis.
14 citations
TL;DR: It is demonstrated that accommodative training may be useful in improving near vision in patients with accommodating IOLs and linked to increases in aberrations and pupil size.
Abstract: Purpose To investigate objective measures of the effects of accommodative training of a pseudophakic eye implanted with a Crystalens AT-52SE (eyeonics Inc) intraocular lens (IOL) on reading performance, accommodation, and depth of focus. Methods Objective dynamic measures of accommodation, pupil size, and depth of focus were quantified from wavefront measures before and after 1 week of accommodative training that began 29 months after implantation of an accommodating IOL in one patient. Depth of focus was estimated from 50% cut-off of peak performance levels for defocus curves that were computed from the image quality metric VSOTF based on ocular wavefront aberrations. Results The patient reported improved near vision reading performance after completing the training procedure. After training, there was a shift in conjugate focus in the hyperopic direction, yet the depth of focus increased significantly for near objects. Simulated retinal images and the calculated modulation transfer function of the eye both demonstrated improved quality for near vision after training. Conclusions The subjective report of improved near vision after training was correlated with improvement of objective measures. Depth of focus increased for near objects with attempts to accommodate after training. This change was linked to increases in aberrations and pupil size and occurred despite the conjugate focus shifting in the hyperopic direction. These results demonstrate that accommodative training may be useful in improving near vision in patients with accommodating IOLs.
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TL;DR: A contextual effect in which the magnitude of the PSD for a target was influenced by the synchronous presentation of another target was described, suggesting that perceptual grouping could play a key role in preserving shape constancy during saccadic eye movements.
Abstract: Perisaccadic spatial distortion (PSD) occurs when a target is flashed immediately before the onset of a saccade and it appears displaced in the direction of the saccade. In previous studies, the magnitude of PSD of a single target was affected by multiple experimental parameters, such as the target's luminance and its position relative to the central fixation target. Here we describe a contextual effect in which the magnitude of the PSD for a target was influenced by the synchronous presentation of another target: PSD for simultaneously presented targets was more uniform than when each was presented individually. Perisaccadic compression was ruled out as a causal factor, and the results suggest that both low- and high-level perceptual grouping mechanisms may account for the change in PSD magnitude. We speculate that perceptual grouping could play a key role in preserving shape constancy during saccadic eye movements.