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Journal of Ophthalmology
Volume 2016, Article ID 7950690, 5 pages
http://dx.doi.org/10.1155/2016/7950690
Research Article

Effects of Target Size and Test Distance on Stereoacuity

1Doctor’s Program of Medical Science, Kitasato University Graduate School, Kitasato, Sagamihara 252-0373, Japan
2Department of Rehabilitation, Orthoptics and Visual Science Course, School of Allied Health Sciences, Kitasato University, Kitasato, Sagamihara 252-0373, Japan
3Department of Ophthalmology, School of Medicine, Kitasato University, Kitasato, Sagamihara 252-0373, Japan

Received 6 May 2016; Revised 13 July 2016; Accepted 27 July 2016

Academic Editor: Edward Manche

Copyright © 2016 Yo Iwata et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Target size and test distance effects on stereoacuity were investigated in 24 subjects using a three-dimensional monitor. Examination 1: Target Size Effects. The test distance was 2.5 m for 0.1°, 0.2°, 0.5°, and 0.9° target sizes; crossed parallax was presented in 22-second units. Average stereoacuity values for 0.1°, 0.2°, 0.5°, and 0.9° target sizes were , , , and seconds, respectively. Stereoacuity was significantly worse with a 0.1° target than with 0.2°, 0.5°, and 0.9° target sizes (, , and , resp.). Examination 2: Test Distance Effects. Test distances of 2.5, 5.0, and 7.5 m were investigated for a 0.5° target size; crossed parallax was presented in 22-second units. Average stereoacuity values at 2.5 m, 5.0 m, and 7.5 m test distances were , , and seconds, respectively. Stereoacuity at a 7.5 m distance was significantly better than at distances of 2.5 m and 5.0 m ( and , resp.). Stereoacuity at a 5.0 m distance was significantly better than at 2.5 m (). Stereoacuity should be estimated by both parallax and other elements, including test distance and target size.