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Journal Article

Citation

Gothwal VK, Wright T, Lamoureux EL, Pesudovs K. Invest. Ophthalmol. Vis. Sci. 2009; 50(9): 4496-4501.

Affiliation

NH&MRC Centre for Clinical Eye Research, Department of Ophthalmology, Flinders Medical Centre and Flinders University of South Australia, Bedford Park, Flinders Drive, Adelaide, South Australia, 5042, Australia.

Copyright

(Copyright © 2009, Association for Research in Vision and Ophthalmology)

DOI

10.1167/iovs.08-3330

PMID

19369236

Abstract

PURPOSE. The Distance Vision Scale (DVS) is a self assessment of visual acuity (VA). Like VA testing where letter reading becomes progressively difficult through the test, the questions of the DVS have a hierarchy of difficulty (Guttman scale). The aims were to determine if the DVS fulfils Guttman scaling criteria and to test the relationship between DVS score and VA in a cataract population. METHODS. The responses of 113 participants to the DVS were subjected to Guttman analysis. The standard criteria of scalability were evaluated that included the coefficient of reproducibility (CR), minimal marginal reproducibility (MMR) and coefficient of scalability (CS). The relationship between the total item score and binocular visual acuity was determined. RESULTS. Five participants were excluded due to missing data. There was regularity in the banding pattern of the scalogram of the 108 participants suggestive of a deterministic Guttman scale. The analyses showed that DVS satisfies the criteria for classification as a valid unidimensional and cumulative scale, as CS (0.93), CR (0.99) and MMR (0.85) values fall within the desired range. The statistically significant correlation between the total item score and binocular VA was 0.24. CONCLUSIONS. The DVS fit the Guttman scale supporting the deterministic model underlying the scale. The DVS correlates poorly with VA, suggesting it taps aspects of visual performance and other issues beyond high contrast VA. The DVS could be used as an outcome measure to evaluate change over time and could be used to set achievable treatment objectives due to its hierarchical properties.


Language: en

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