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Lookup NU author(s): Dr Kathleen Vancleef,
Dr Ignacio Serrano-Pedraza
This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).
© 2017 The College of Optometrists. Purpose: It has been repeatedly shown that the TNO stereotest overestimates stereo threshold compared to other clinical stereotests. In the current study, we test whether this overestimation can be attributed to a distinction between 'global' (or 'cyclopean') and 'local' (feature or contour-based) stereopsis. Methods: We compared stereo thresholds of a global (TNO) and a local clinical stereotest (Randot Circles). In addition, a global and a local psychophysical stereotest were added to the design. One hundred and forty-nine children between 4 and 16 years old were included in the study. Results: Stereo threshold estimates with TNO were a factor of two higher than with any of the other stereotests. No significant differences were found between the other tests. Bland-Altman analyses also indicated low agreement between TNO and the other stereotests, especially for higher stereo threshold estimates. Simulations indicated that the TNO test protocol and test disparities can account for part of this effect. Discussion: The results indicate that the global - local distinction is an unlikely explanation for the overestimated thresholds of TNO. Test protocol and disparities are one contributing factor. Potential additional factors include the nature of the task (TNO requires depth discrimination rather than detection) and the use of anaglyph red/green 3D glasses rather than polarizing filters, which may reduce binocular fusion.
Author(s): Vancleef K, Read JCA, Herbert W, Goodship N, Woodhouse M, Serrano-Pedraza I
Publication type: Article
Publication status: Published
Journal: Ophthalmic and Physiological Optics
Print publication date: 01/07/2017
Online publication date: 23/03/2017
Acceptance date: 09/02/2017
Date deposited: 03/05/2017
ISSN (print): 0275-5408
ISSN (electronic): 1475-1313
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