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Blur limits for defocus, astigmatism and trefoil

Atchison, David A., Guo, Huanqing, Charman, W. Neil, & Fisher, S. W. (2009) Blur limits for defocus, astigmatism and trefoil. Vision Research, 49(14), pp. 2393-2403.

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Abstract

We investigated the limits at which blur due to defocus, crossed-cylinder astigmatism, and trefoil became noticeable, troublesome or objectionable. Black letter targets (0.1, 0.35 and 0.6 logMAR) were presented on white backgrounds. Subjects were cyclopleged and had effectively 5 mm pupils. Blur was induced with a deformable, adaptive-optics mirror operating under open-loop conditions. Mean defocus blur limits of six subjects with uncorrected intrinsic higher-order ocular aberrations ranged from 0.18 ± 0.08 D (noticeable blur criterion, 0.1 logMAR) to 1.01 ± 0.27 D (objectionable blur criterion, 0.6 logMAR. Crossed-cylinder astigmatic blur limits were approximately 90% of those for defocus, but with considerable meridional influences. In two of the subjects, the intrinsic aberrations of the eye were subsequently corrected before the defocus and astigmatic blur were added. This resulted in only minor reductions in their blur limits. When assessed with trefoil blur and corrected intrinsic ocular aberrations, the ratio of objectionable to noticeable blur limits in these two subjects was much higher for trefoil (3.5) than for defocus (2.5) and astigmatism (2.2).

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24 citations in Web of Science®

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ID Code: 29548
Item Type: Journal Article
Additional URLs:
Keywords: Aberration, Adaptive Optics, Astigmatism, Blur limits, defocus, Trefoil
DOI: 10.1016/j.visres.2009.07.009
ISSN: 0042-6989
Subjects: Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300)
Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300) > Vision Science (111303)
Divisions: Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Current > Schools > School of Optometry & Vision Science
Copyright Owner: Copyright 2009 Elsevier
Deposited On: 08 Jan 2010 09:29
Last Modified: 01 Mar 2012 00:08

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