Induced vertical disparity effects on local and global stereopsis


Purpose: Although significant amounts of vertical misalignment could have a noticeable effect on visual performance, there is no conclusive evidence about the effect of very small amount of vertical disparity on stereopsis and binocular vision. Hence, the aim of this study was to investigate the effects of induced vertical disparity on local and global stereopsis at near. Materials and Methods: Ninety participants wearing best-corrected refraction had local and global stereopsis tested with 0.5 and 1.0 prism diopter (Δ) vertical prism in front of their dominant and non-dominant eye in turn. This was compared to local and global stereopsis in the same subjects without vertical prism. Data were analyzed in SPSS.17 software using the independent samples T and the repeated measures ANOVA tests. Results: Induced vertical disparity decreases local and global stereopsis. This reduction is greater when vertical disparity is induced in front of the non-dominant eye and affects global more than local stereopsis. Repeated measures ANOVA showed differences in the mean stereopsis between the different measured states for local and global values. Local stereopsis thresholds were reduced by 10s of arc or less on average with 1.0Δ of induced vertical prism in front of either eye. However, global stereopsis thresholds were reduced by over 100s of arc by the same 1.0Δ of induced vertical prism. Conclusion: Induced vertical disparity affects global stereopsis thresholds by an order of magnitude (or a factor of 10) more than local stereopsis. Hence, using a test that measures global stereopsis such as the TNO is more sensitive to vertical misalignment than a test such as the Stereofly that measures local stereopsis. © 2014 Informa Healthcare USA, Inc. All rights reserved: reproduction in whole or part not permitted.

Publication DOI:
Divisions: College of Health & Life Sciences > School of Optometry > Optometry & Vision Science Research Group (OVSRG)
College of Health & Life Sciences
College of Health & Life Sciences > School of Optometry > Vision, Hearing and Language
College of Health & Life Sciences > School of Optometry > Optometry
Uncontrolled Keywords: binocular vision,dominant eye,global stereopsis,local stereopsis,vertical heterophoria,Ophthalmology,Sensory Systems,Cellular and Molecular Neuroscience
Publication ISSN: 1460-2202
Last Modified: 08 Dec 2023 09:39
Date Deposited: 30 Sep 2013 13:27
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Related URLs: http://www.scop ... tnerID=8YFLogxK (Scopus URL)
http://informah ... 683.2013.822895 (Publisher URL)
PURE Output Type: Article
Published Date: 2014-04
Published Online Date: 2013-09-16
Authors: Momeni-Moghaddam, Hamed
Eperjesi, Frank (ORCID Profile 0000-0003-4358-0095)
Kundart, James
Sabbaghi, Hamideh



Version: Accepted Version

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