Haque, S., Toor, S. orcid.org/0000-0003-3209-5318 and Buckley, D. orcid.org/0000-0001-9140-8543 (2024) Are horizontal fusional vergences comparable when measured using a prism bar and synoptophore? British and Irish Orthoptic Journal, 20. pp. 85-93. ISSN 2516-3590
Abstract
Aim: To determine whether horizontal fusional vergences are comparable when measured using a prism bar and synoptophore.
Methods: Thirty two participants (18–23 years) had their blur, break, and recovery points measured for convergence and divergence amplitudes using a prism bar (6 m) and synoptophore. All participants had VA of 0.1 LogMAR or better in either eye, were heterophoric or orthophoric and had binocular single vision. The prism bar target was a 0.2 LogMAR letter. The synoptophore target was the foveal ‘rabbit’ fusion slides. The prism bar was placed over the dominant eye and the testing speed was two seconds per two prism dioptres (Δ), increasing to five seconds per 5Δ when the increments began to increase in 5Δ. Synoptophore testing speed was two seconds per degree.
Results: The synoptophore measured significantly higher convergence break points than the prism bar (Z = 3.37, p = 0.001). No significant differences were found between both tests for divergence break points (Z = 0.99, p = 0.32). However, both tests displayed wide limits of agreement (LoA) when measuring convergence (–24Δ to + 49.59Δ) and divergence break points (–7.70Δ to + 10.19Δ). Differences when measuring convergence and divergence blur and recovery points were not statistically significant.
Conclusion: There was a statistically and clinically significant difference when measuring convergence break points using the prism bar and synoptophore but no significant difference when measuring divergence break points. However, both tests displayed wide LoA when measuring convergence and divergence break points, indicating they should not be used interchangeably in clinic to measure horizontal fusional vergences.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2024 The Author(s). This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International License (CC-BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. See http://creativecommons.org/licenses/by/4.0/. |
Keywords: | Fusional vergences; prism bar; synoptophore |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Medicine, Dentistry and Health (Sheffield) > Health Sciences School (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 15 Aug 2024 10:28 |
Last Modified: | 15 Aug 2024 10:28 |
Status: | Published |
Publisher: | White Rose University Press |
Refereed: | Yes |
Identification Number: | 10.22599/bioj.326 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:216159 |