Sensory adaptation to blur improves visual acuity under defocused
conditions. This phenomenon has been successfully demonstrated using
subjective measures of acuity and is known as blur adaptation. This study
investigates aspects of the mechanism of blur adaptation in human vision
using subjective and objective methods.
Parafoveal visual acuity measured under defocused conditions demonstrates
that blur adaptation is not limited to the fovea. The presence of the adaptive
mechanism in the parafovea also suggests that the neural compensation that
takes places under defocused conditions acts across a spatial range and is
not limited to specific frequency bands. An evaluation of the contrast
sensitivity function under defocus provides further evidence.
Electrophysiological methods measure the effect of blur adaptation at the
retina and at the visual cortex to provide objective evidence for the presence
of the blur adaptation mechanism. Finally enhanced-depth imaging optical
coherence tomography examines whether a period of prolonged defocus
triggers any short-term changes in choroidal thickness in a similar manner to
that reported in animal emmetropisation. / Engineering and Physical Sciences Research Council
| Identifer | oai:union.ndltd.org:BRADFORD/oai:bradscholars.brad.ac.uk:10454/6329 |
| Date | January 2013 |
| Creators | Mankowska, Aleksandra |
| Contributors | Mallen, Edward A.H., McKeefry, Declan J. |
| Publisher | University of Bradford, Bradford School of Optometry and Vision |
| Source Sets | Bradford Scholars |
| Language | English |
| Detected Language | English |
| Type | Thesis, doctoral, PhD |
| Rights | <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />The University of Bradford theses are licenced under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/">Creative Commons Licence</a>. |
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