FIR A Digital Storage Space

A Comparison Of Risley And Bar Vergences.

Show simple item record Becker, David 2014-02-20T21:01:40Z 2014-02-20T21:01:40Z 1986-05-09
dc.description This paper is submitted in partial fulfillment of the requirements for the degree of Doctor of Optometry. 8 pages. en_US
dc.description.abstract Recently mechanisms but there has been interest in disparity measurement of them clinically has not and vergence kept pace. Right now the most popular way of measuring fusional vergence reserves is with the Risley prisms in a phoropter. However, recently Vaegan and Pye demonstrated the use of a motorized prism stereoscope to measure vergences at near but data from their study agree with reported values for break and recovery for both convergence and divergence measured with prisms in the phoropter. This is fine but ideally it would be better to measure vergences in a more natural environment . The Beren's 15 prism bar allows this. A patient has peripheral cues and so is more aware of his surroundings and normal spatialization. Another reason the prism bar is more natural is that a patient must make step vergence movements instead of a ramp type movement with a Risley prism. When a person looks from far to near, such as from the blackboard at school to his paper he is taking notes on, he makes a step vergence. Probably the biggest advantage of the prism bar is its use in children. The break and recovery points can be viewed objectively by observing the eye-turn and fusional movements respectfully. The only problem with this is the difficulty in seeing small angle loss of fusion. In this case a subjective response is required. There have been studies done which have found normals for near and far vergences with Risley prisms in a phoropter. What I want to do in this study is compare Risley prism and bar prism vergences and also take into consideration eye dominancy. en_US
dc.language.iso en_US en_US
dc.relation.ispartofseries UA 29;
dc.subject Vergence en_US
dc.subject Fixation disparity en_US
dc.subject Measurement en_US
dc.title A Comparison Of Risley And Bar Vergences. en_US
dc.type Thesis en_US

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