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Manonmani Murugappan, Andrea M Janoff, Luis Andres Lesmes, Emma Flor, Maryn JaNet Barnes, Ava K Bittner; The repeatability of visual changes measured with tests of visual acuity and contrast sensitivity. Invest. Ophthalmol. Vis. Sci. 2019;60(9):5904.
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The recent applications of active learning algorithms to testing visual acuity (VA) and contrast sensitivity function (CSF) – quantitative VA (qVA) and quantitative CSF (qCSF) – reflect an attempt to develop tools with higher stimulus resolution, better test precision, and improved detection of vision changes related to intervention or ocular disease progression. We compared the test-retest repeatability of the qVA and qCSF tests to the standard ETDRS VA and Pelli-Robson CS charts.
At two visits about one week apart, the same test battery was repeated, involving two measures of distance VA (ETDRS trans-illuminated chart and qVA) and two tests of distance CS (Pelli-Robson and qCSF) in a total of 50 eyes in 25 normally-sighted, pre-presbyopic adults without ocular disease. Subjects performed all tests with daily disposable Acuvue or Alcon contact lenses with distance-only and multifocal correction to introduce some visual degradation. Between-visit repeatability was determined with 95% coefficients of repeatability (CR).
For the two visual conditions, 95% CRs for distance-only and multifocal correction were 0.18 and 0.18 log units for ETDRS VA, 0.12 and 0.16 log units for qVA, 0.20 and 0.21 logCS for Pelli-Robson, and 0.23-0.25 and 0.24-0.29 logCS for qCSF area under the log curve (AUC) or at 1.5, 3 and 6 cpd, respectively. The magnitude of vision loss with the multifocal lens was not significantly different between the two visits for each of the four tests (all p>0.05). Cohen’s d effect size reflects both the magnitude of visual change and test repeatability, which was 1.16 and 1.61 for ETDRS VA and qVA, respectively, 0.77 for Pelli-Robson CS, 1.20 for qCSF AUC, and 0.31, 0.75, and 1.11 for qCSF at 1.5, 3 and 6 cpd, respectively.
As part of central visual function test validation and selection, it is important to determine and consider both the test repeatability and magnitude of visual changes of interest that are documented with each test. Improving Cohen’s d effect size for detected visual changes has the potential to reduce sample sizes in clinical trials.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.
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