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http://dx.doi.org/10.3807/JOSK.2013.17.2.219

Predicting of Uncorrected Astigmatism from Decimal Visual Acuity in Spherical Equivalent  

Moon, Byeong-Yeon (Department of Optometry, Kangwon National University)
Kim, Sang-Yoeb (Department of Optometry, Kangwon National University)
Cho, Hyun Gug (Department of Optometry, Kangwon National University)
Publication Information
Journal of the Optical Society of Korea / v.17, no.2, 2013 , pp. 219-223 More about this Journal
Abstract
The purpose of this study was to determine the relationship between the spherical equivalent visual acuity (VA) and uncorrected astigmatism. On 108 emmetropic eyes, the spherical equivalent VA was measured for cross cylindrical lens (CC lens)-induced astigmatic eyes and the VA-astigmatism relation determined. On 158 astigmatic eyes, the spherical equivalent VA and corrected astigmatism were measured and the measured values were compared with the calculated values from the VA-astigmatism relation by correlation coefficient analysis. Subsequent to that, the relationship between spherical equivalent VA and uncorrected astigmatism was made. The relationship was fitted for an exponential equation. Correlation coefficient between calculated values by equation and measured values for astigmatic eyes was 0.991 (p<0.01). The relationship between the spherical equivalent VA and the uncorrected astigmatism was decided as follows (spherical equivalent VA / uncorrected astigmatism): 1.0 / 0.25 D, 0.9 / 0.50 D, 0.8 / 0.75 D, 0.7 / 1.00 D, 0.6 / 1.25 D, 0.5 / 1.50 D, 0.4 / 2.00 D, 0.3 / 2.50 D, 0.2 / 3.00 D, 0.1 / 4.00 D, and 0.05 / 4.75 D. In conclusion, the relationship table devised from this study is a useful reference for predicting uncorrected astigmatism by measurement of decimal VA in spherical equivalent.
Keywords
Predicting uncorrected astigmatism; Spherical equivalent; Decimal visual acuity;
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