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| Volume 7, Number 9, Abstract 519, Page 519a |
doi:10.1167/7.9.519 |
http://journalofvision.org/7/9/519/ |
ISSN 1534-7362 |
Crowding accounts for the limits of amblyopic reading
Denis Pelli |
Psychology and Neural Science, New York University |
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Shuang Song |
School of Optometry, University of California at Berkeley |
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Dennis Levi |
School of Optometry, University of California at Berkeley, and Helen Wills Neuroscience Institute, University of California at Berkeley |
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Abstract
Might the impairment of reading in amblyopia be a consequence of increased crowding (i.e. larger critical spacing)? We measured the reading rate of amblyopes as a function of letter spacing in central and peripheral vision. From these results, we estimate the "critical spacing for reading" (similar to critical print size). We find that the amblyopic reading deficit is large but very specific. Peripheral reading is unaffected. Central reading has greatly increased critical spacing, but normal maximum reading rate. We compared the critical spacing for reading with the observers' letter acuity and the critical spacing for identifying a letter among flankers, which is the classic measure of crowding (Bouma, 1970). For both normals and amblyopes, in both central and peripheral vision, we find that the critical spacing for reading equals the critical spacing for crowding.
EY04432, EY01728
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