Noticable, troublesome and objecttionable limits of blur
We investigated limits at which induced blur becomes noticeable, troublesome and objectionable. We used 15 cyclopleged subjects, a Badal optometer with lines of three high contrast letters as targets, 3–6 mm artificial pupils, and 0.0–0.7 logMAR letter sizes. For 0.0 logMAR size, mean ‘‘noticeable’’ blur limits were ±0.33D, ±0.30D and ±0.28D at 3 mm, 4 mm and 6 mm, respectively, but increased by about 70% for 0.7 logMAR letters. All limits reduced by about 17% as pupil size increased from 3 mm to 6 mm. Letter size had a significant influence on all blur limits (1.6–2.1 times), but blur direction had no significant effect. Magnitudes of ‘‘troublesome’’ and objectionable’’ limits were 1.6–1.8 times and 2.1–2.5 times relative to ‘‘noticeable’’ limits, respectively. Our results suggest criteria for troublesome and objectionable blur are relatively unaffected by letter size.
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|Item Type:||Journal Article|
|Additional Information:||For more information, please refer to the journal’s website (see link) or contact the author. Author contact details: firstname.lastname@example.org|
|Keywords:||Blur limits, Defocus, Letter size, Pupil size, Visual acuity|
|Subjects:||Australian and New Zealand Standard Research Classification > MEDICAL AND HEALTH SCIENCES (110000) > OPTOMETRY AND OPHTHALMOLOGY (111300)|
|Divisions:||Current > QUT Faculties and Divisions > Faculty of Health|
Current > Institutes > Institute of Health and Biomedical Innovation
|Copyright Owner:||Copyright 2005 Elsevier|
|Copyright Statement:||Reproduced in accordance with the copyright policy of the publisher.|
|Deposited On:||14 Nov 2006|
|Last Modified:||29 Feb 2012 23:15|
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