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The effects of positive and negative lenses on the accommodative-convergence/accommodation ratio

M.Phil. (Optometry) / The accommodative-convergence accommodation (AC/A) ratio is a commonly used relationship in the practice of optometry. Many practitioners make use of the AC/A ratio as an aid to diagnostic and prognostic decisions. It is not perfectly clear what effects positive and negative lenses have on the AC/A ratio. A number of questions remain relating to linearity, symptomatology and equality of lens effects on the AC/A ratio. This experiment was designed and conducted in an attempt to answer some of these unanswered questions and forms the foundation of this thesis. A literature review of available knowledge related to this study is detailed. An instrument is described which was constructed to measure the necessary accommodation and vergence changes induced by various stimuli. A sample of first year students at the Rand Afrikaans University department of Optometry was selected according to various acceptance criteria. A total of 109 students were screened , of which a group of 26 students was subjected to the experimental investigation. The data were then subjected to a statistical analysis in an attempt to reveal correlations, linearity and group formations.

Identiferoai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:uj/uj:3899
Date11 February 2014
CreatorsGillan, W.D.H.
Source SetsSouth African National ETD Portal
Detected LanguageEnglish
TypeThesis
RightsUniversity of Johannesburg

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