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Sunil Shah, Phillip J. Buckhurst, James S. Wolffsohn, Shehzad Naroo, Leon N. Davies; Evaluation Of Reading Ability And Near Vision Satisfaction. Invest. Ophthalmol. Vis. Sci. 2011;52(14):5564. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
To validate a visual related quality of life questionnaire and to use it to assess the most appropriate metric for assessing reading ability with pseudophakic subjects.
Following cataract extraction, 110 patients were implanted bilaterally with monofocal (n=20), concentric refractive multifocal (n=15), concentric diffractive multifocal (n=15), a combination of concentric refractive and diffractive multifocal (n=15), sectorial refractive (n=15) and single-optic accommodative (n=30) IOLs. The MNRead was used to calculate Maximum reading Speed (MRS), Critical Print Size (CPS) and reading acuity (RA). Asymototic curves were fitted to the MNread dataset and a new metric; reading area, was derived using the integration limits of 1.0 logMAR and the RA. Twenty-three previously used near vision questions were reduced and validated using Rasch analysis to create the Near Activity Visual Questionnaire (NAVQ) which was used to compare the reading metrics with subjective near visual ability.
The reduced NAVQ consisted of 9 items with a Cronbach Alpha coefficent of 0.945, a Rasch separation index of 2.78, reliability index of 0.89 and test-retest reliability of 0.715. A linear regression stepwise model showed that the reading area metric accounted for 57% of the NAVQ assessed subjective near ability, with a further 2% contribution combining it with the CPS. However the calculation of CPS scores was affected by interobserver error (ICC=-0.761). Reading area was greater with all patient groups implanted with multifocal IOLs in comparison with the monofocal IOL group (p=0.001) and the single-optic accommodative IOL group (p<0.050). Reading area was also greater in the sectorial refractive IOL group compared to the concentric refractive IOL group (p=0.038).
The NAVQ is a valid and repeatable instrument for the assessment of near visual satisfaction with presbyopic corrections. The reading area metric is a new single metric for the assessment of reading vision that correlates well with the subjective rating of near vision and differentiates between multifocal IOL designs.
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