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PURPOSE Perceptual learning has been shown to be effective in improving visual functions in the normal adult visual system, as well as in adults with amblyopia. In this study, the feasibility of applying perceptual learning to enhance reading speed in people with long-standing central vision loss was evaluated. METHODS Six observers (mean age, 73.8) with(More)
Single-unit recordings demonstrated that the adult mammalian visual cortex is capable of reorganizing after induced retinal lesions. In humans, whether the adult cortex is capable of reorganizing has only been studied using functional magnetic resonance imaging, with equivocal results. Here, we exploited the phenomenon of visual crowding, a major limitation(More)
In this study, we examined the effects of contrast and spatial frequency on reading speed and compared these effects between the normal fovea and periphery. We found that when text contrast was low, reading speed demonstrated spatial-frequency tuning properties, with a peak tuning frequency that partially scaled with print size. The spatial-frequency tuning(More)
PURPOSE Acuity measurement is a fundamental method to assess visual performance in the clinic. Little is known about how acuity measured in the presence of neighboring letters, as in the case of letter charts, changes with contrast and with nonfoveal viewing. This information is crucial for acuity measurement using low-contrast charts and when patients(More)
PURPOSE Crowding, the difficulty in recognizing a letter in close proximity with other letters, has been suggested as an explanation for slow reading in people with central vision loss. The goals of this study were (1) to examine whether increased letter spacing in words, which presumably reduces crowding among letters, would benefit reading for people with(More)
Crowding between adjacent letters has been investigated primarily as a spatial effect. The purpose of this study was to investigate the spatio-temporal properties of letter crowding. Specifically, we examined the systematic changes in the degradation effects in letter identification performance when adjacent letters were presented with a temporal(More)
BACKGROUND Vision in people with autism spectrum conditions (ASC) is reported to be different from people without ASC, but the neural level at which the differences begin to occur is not yet known. Here we examine two variants of a vernier acuity task to determine if differences are evident in early visual processing. FINDINGS Abutting and separated(More)
PURPOSE Crowding, the adverse spatial interaction due to the proximity of adjacent targets, has been suggested as an explanation for slow reading in peripheral vision. Previously, we showed that increased line spacing, which presumably reduces crowding between adjacent lines of text, improved reading speed in the normal periphery (Chung, Optom Vis Sci(More)
Objects that are briefly flashed around the time of saccades are mislocalized. Previously, robust interactions between saccadic perceptual distortions and stimulus contrast have been reported. It is also known that crowding depends on the contrast of the target and flankers. Here, we investigated how stimulus contrast and crowding interact with pre-saccadic(More)