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KMID : 1011420150200030349
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Journal of Korean Ophthalmic Optics Society
2015 Volume.20 No. 3 p.349 ~ p.354
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Changes of Corrective Astigmatism Values Depending on Position of Circle of Least Confusion in Astigmatic Refining Test Using Cross Cylinder
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Kim Sang-Yeob
Lee Min-Jae
Lee Kang-Cheon
Lee Tae-Hui
Moon Byeong-Yeon
Cho Hyun-Gug
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Abstract
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Purpose: To investigate the changes of corrective values of astigmatism caused by the position of circle of least confusion on retina in refining astigmatic test using cross cylinder.
Methods: 62 subjects (115 eyes) aged 22.24±2.48 years participated for this study. After astigmatic test using a radial chart, refining test was performed using a cross cylinder in a condition of maximum plus to maximum visual acuity (MPMVA). Astigmatic refining test was repeatedly performed in each condition of which S+0.75 D, S+0.50 D, S+0.25 D, S-0.25 D, S-0.50 D, and S-0.75 D are added to spherical lenses of MPMVA. The measured values were compared with the values in MPMVA condition.
Results: As compared with values in condition of MPMVA, change of astigmatic axis was increased with add the power of (+) spherical lenses and (?) spherical lenses. In same spherical condition, change of astigmatic axis was decreased with increment of astigmatic power (p<0.05). The corrective power of astigmatism was reduced with increment of (+) spherical lenses (p<0.05), and was raised with increment of (?) spherical lenses compared with the power in MPMVA condition. In case of adding (+) spherical lenses, difference of astigmatic power increased with increment of corrective astigmatism power in same test condition.
Conclusions: In order to obtain a proper values for corrective astigmatism, position of circle of least confusion
should be accurately adjusted before the performing an astigmatism’s refining test.
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KEYWORD
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Cross cylinder, Refining test for astigmatism, Position of circle of least confusion, Corrective astigmatism axis, Corrective astigmatism power
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