Mon-Williams, M., Tresilian, J.R., Strang, N.C., Kochhar, P. and Wann, J.P. (1998) Improving vision: neural compensation for optical defocus. Proceedings of the Royal Society B: Biological Sciences, 265 (1390). pp. 71-77. ISSN 0962-8452Full text not available from this repository.
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 the defocus 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.
|Keywords:||human vision, blur, adaptation, neural compensation|
|Institution:||The University of Leeds|
|Academic Units:||The University of Leeds > Faculty of Medicine and Health (Leeds) > Institute of Psychological Sciences (Leeds) > Cognitive Psychology (Leeds)|
|Depositing User:||Repository Officer|
|Date Deposited:||18 Jun 2009 14:23|
|Last Modified:||29 Sep 2010 14:24|