Functional near vision assessment in presbyopia
The aim of this thesis was to develop standards of best practice for the subjective assessment of near visual function in presbyopia. Near visual acuity (VA) is a quick and simple measure but an assessment of the maximum reading speed and the smallest print size that can maintain this are equally im...
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ndltd-bl.uk-oai-ethos.bl.uk-4938822017-04-20T03:25:35ZFunctional near vision assessment in presbyopiaGupta, Navneet2008The aim of this thesis was to develop standards of best practice for the subjective assessment of near visual function in presbyopia. Near visual acuity (VA) is a quick and simple measure but an assessment of the maximum reading speed and the smallest print size that can maintain this are equally important, to gain a better reflection of real world visual function. These metrics are dependent on the amplitude of accommodation (AoA) and often this must be evaluated using subjective techniques. Defocus curves are less susceptible than the push-up/push-down test to the influence of blur tolerance but their implementation must be standardised such that letter sequences and the order of lens presentation are randomised, to avoid memory effects, whilst the AoA should be quantified as the range of defocus for which only the best VA is maintained. In addition to such clinical assessments, subjective questionnaire evaluations are also important, to determine whether at least an individual's needs are met. The Near Activity Visual Questionnaire (NAVQ) developed in this thesis can be used for this. Using these standardised near vision metrics it is shown that visual performance with monovision and multifocal contact lenses is comparable whilst initial outcomes of single optic 'accommodating' intraocular lens implantation are unlikely to be sustained in the long-term.617.755OptometryAston Universityhttp://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493882http://publications.aston.ac.uk/14643/Electronic Thesis or Dissertation |
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617.755 Optometry |
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617.755 Optometry Gupta, Navneet Functional near vision assessment in presbyopia |
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The aim of this thesis was to develop standards of best practice for the subjective assessment of near visual function in presbyopia. Near visual acuity (VA) is a quick and simple measure but an assessment of the maximum reading speed and the smallest print size that can maintain this are equally important, to gain a better reflection of real world visual function. These metrics are dependent on the amplitude of accommodation (AoA) and often this must be evaluated using subjective techniques. Defocus curves are less susceptible than the push-up/push-down test to the influence of blur tolerance but their implementation must be standardised such that letter sequences and the order of lens presentation are randomised, to avoid memory effects, whilst the AoA should be quantified as the range of defocus for which only the best VA is maintained. In addition to such clinical assessments, subjective questionnaire evaluations are also important, to determine whether at least an individual's needs are met. The Near Activity Visual Questionnaire (NAVQ) developed in this thesis can be used for this. Using these standardised near vision metrics it is shown that visual performance with monovision and multifocal contact lenses is comparable whilst initial outcomes of single optic 'accommodating' intraocular lens implantation are unlikely to be sustained in the long-term. |
author |
Gupta, Navneet |
author_facet |
Gupta, Navneet |
author_sort |
Gupta, Navneet |
title |
Functional near vision assessment in presbyopia |
title_short |
Functional near vision assessment in presbyopia |
title_full |
Functional near vision assessment in presbyopia |
title_fullStr |
Functional near vision assessment in presbyopia |
title_full_unstemmed |
Functional near vision assessment in presbyopia |
title_sort |
functional near vision assessment in presbyopia |
publisher |
Aston University |
publishDate |
2008 |
url |
http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.493882 |
work_keys_str_mv |
AT guptanavneet functionalnearvisionassessmentinpresbyopia |
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1718440688628006912 |