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KMID : 1159320180200020137
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Korean Journal of Vision Science
2018 Volume.20 No. 2 p.137 ~ p.149
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Change of Refraction while Viewing through the Periphery of Spectacle Lens
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Moon Byeong-Yeon
Sa Jong-Hwan
Yu Dong-Sik
Kim Sang-Yeob
Cho Hyun-Gug
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Abstract
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Purpose : The purpose of this study was to investigate the change of refraction while viewing through the periphery of spectacle lens.
Methods : In order to measure the change of refractive power while viewing through the periphery of the lens, the refractive power was measured with a digital lensmeter when the lens was tilted by gaze angle around a rotation axis which was 25 mm below from the lens support of lensmeter, and compared with refractive powers measured at the optical center and periphery. The effects of the refraction caused by the changes of lens thickness and vertex distance according to the gaze angle were also examined.
Results : The thickness of a lens at a point of gaze was increased with the increase of the gaze angle, but not so much as to affect the correction power. As the gaze angle increased, the vertex distance increased and additional (-) correction power was required. At the gaze angles within 30?, the additional power was less than -0.1D. In most cases, as the gaze angle increased, the minimum refractive power (spherical power) was not significantly different from the reference refractive power. Cylindrical power was hardly observed up to about 10?, but increased with increasing the gaze angle.
Conclusions : The change of refractive power caused by aberrations such as astigmatism in the peripheral vision should be considered in the use environment and handling of lenses.
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KEYWORD
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Gaze angle, Refractive power, Peripheral vision, Astigmatism, Vertex distance
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