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Changes of Corrective Astigmatism Values Depending on Position of Circle of Least Confusion in Astigmatic Refining Test Using Cross Cylinder

크로스실린더를 이용한 난시정밀검사에서 검사 전 최소착란원 위치에 따른 난시교정값의 변화

  • Received : 2015.08.01
  • Accepted : 2015.08.19
  • Published : 2015.09.30

Abstract

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 $22.24{\pm}2.48$ 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.

Keywords

Cross cylinder;Refining test for astigmatism;Position of circle of least confusion;Corrective astigmatism axis;Corrective astigmatism power

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  1. Effect of Visual acuity for Change of Astigmatism axis in Myopic astigmatism vol.13, pp.12, 2015, https://doi.org/10.14400/JDC.2015.13.12.285
  2. Effect of Undercorrected Astigmatism on Visual Acuity According to Essential Astigmatism Power vol.23, pp.4, 2018, https://doi.org/10.14479/jkoos.2018.23.4.415