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Modeling logMAR visual acuity scores: effects of termination rules and alternative forced-choice options

Carkeet, Andrew D. (2001) Modeling logMAR visual acuity scores: effects of termination rules and alternative forced-choice options. Optometry And Vision Science, 78(7), pp. 529-538.

Abstract

BACKGROUND: Logarithm of the minimum angle of resolution (logMAR) charts come in a variety of alternative forced-choice (AFC) formats and can be used with a variety of different rules to determine when to stop a subject reading down a chart (termination rules). METHODS: Exact calculation and Monte Carlo simulation techniques were used to compare logMAR scores for different termination rules and for infinite-, 26-, 10-, 8-, 4-, and 2-AFC logMAR chart formats. Slope-corrected standard deviation, an index of variability of the underlying ideal threshold, was used as a common metric for the different test conditions. RESULTS: The mean and standard deviation of logMAR scores can be significantly affected by termination rules and AFC format. For different AFC formats, different termination criteria were found to give optimal slope-corrected standard deviations. CONCLUSION: A number of clinically suitable termination rules are proposed for different AFC format logMAR charts. For letter-by-letter scoring of Bailey-Lovie and EDTRS charts, it is recommended that researchers and practitioners use a termination rule of stopping after four or more mistakes on a line.

Impact and interest:

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42 citations in Web of Science®

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ID Code: 11877
Item Type: Journal Article
Additional Information: For more information, please refer to the journal’s website (see hypertext link) or contact the author.
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Keywords: visual acuity, modeling, alternative forced choice, termination rules
ISSN: 1040-5488
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 > Research Centres > Centre for Health Research
Current > QUT Faculties and Divisions > Faculty of Health
Current > Institutes > Institute of Health and Biomedical Innovation
Copyright Owner: Copyright 2001 Lippincott Williams Wilkins
Deposited On: 14 Jan 2008
Last Modified: 22 Apr 2010 02:20

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