07/01/1998 Computer Science Medicine Physics
DOI: 10.1098/rspb.1998.0266 SemanticScholar ID: 5541891 MAG: 2045148698

Improving vision: neural compensation for optical defocus

Publication Summary

Anecdotal reports abound of vision improving in myopia after a period of time without refractive correction. We explored whether this effect is due to an increased tolerance of blur, or whether it reflects a genuine improvement in vision. Our results clearly demonstrated a marked improvement in the ability to detect and recognize letters following prolonged exposure to optical defocus. We ensured that ophthalmic change did not occur, and thus the phenomenon must be due to a neural compensation for thedefocus condition. A second set of experiments measured contrast sensitivity and found a decrease in sensitivity to mid–range (5–25) cycles deg−1 spatial frequencies following exposure to optical defocus. The results of the two experiments may be explained by the unmasking of low contrast, high spatial frequency information via a two–stage process: (1) the pattern of relative channel outputs is maintained during optical defocus by the depression of mid–range spatial frequency channels; (2) channel outputs are pooled prior to the production of the final percept. The second set of experiments also provided some evidence of inter–ocular transfer, indicating that the adaptation process is occurring at binocular sites in the cortex.

CAER Authors

Avatar Image for Mark Mon-Williams

Prof. Mark Mon-Williams

University of Leeds - Chair in Cognitive Psychology

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