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Vision Res. 2008 Dec;48(27):2739-50. doi: 10.1016/j.visres.2008.09.009. Epub 2008 Oct 18.

Learning to identify near-threshold luminance-defined and contrast-defined letters in observers with amblyopia.

Author information

1
School of Optometry, University of California, 360 Minor Hall, Berkeley, CA 94720-2020, USA. s.chung@berkeley.edu

Abstract

We assessed whether or not the sensitivity for identifying luminance-defined and contrast-defined letters improved with training in a group of amblyopic observers who have passed the critical period of development. In Experiment 1, we tracked the contrast threshold for identifying luminance-defined letters with training in a group of 11 amblyopic observers. Following training, six observers showed a reduction in thresholds, averaging 20%, for identifying luminance-defined letters. This improvement transferred extremely well to the untrained task of identifying contrast-defined letters (average improvement=38%) but did not transfer to an acuity measurement. Seven of the 11 observers were subsequently trained on identifying contrast-defined letters in Experiment 2. Following training, five of these seven observers demonstrated a further improvement, averaging 17%, for identifying contrast-defined letters. This improvement did not transfer to the untrained task of identifying luminance-defined letters. Our findings are consistent with predictions based on the locus of learning for first- and second-order stimuli according to the filter-rectifier-filter model for second-order visual processing.

PMID:
18824189
PMCID:
PMC2642955
DOI:
10.1016/j.visres.2008.09.009
[Indexed for MEDLINE]
Free PMC Article

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