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KMID : 1011420150200030341
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Journal of Korean Ophthalmic Optics Society
2015 Volume.20 No. 3 p.341 ~ p.347
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Comparison between Response AC/A and CA/C Ratio according to Additional Spherical Powers and Prism Powers
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Roh Byeong-Ho
Yu Dong-Sik
Son Jeong-Sik
Kwak Ho-Wen
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Abstract
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Purpose : This study was to examine a correlation of response AC/A ratio by additional spherical powers with PD(Pupilary distance) and relative accommodation, and was to investigate correlation of CA/C ratio by prism powers. The mean differences between a reciprocal response AC/A ratio and a CA/C ratio were compared, and were suggested to be used as data in the refractive power and prism prescriptions in the clinical.
Methods: The open field autorefractometer (Nvision-K 5001, Shin nippon) and Howell target at 40 cm fixation distance to 62 persons with average 22.62±2.84 ages were used to measure the response AC/A ratio according to additional Spherical powers. The CA/C ratios were measured using the DOG card at 40cm according to prism powers.
Results: When the response accommodation according to Additional Spherical power changes and the response accommodation according to prism power changes were compared, it was larger than the response accommodation
according prism power change. These were significant differences statistically. The correlation of response AC/A ratio and PD is showed as r = ?0.158, the CA / C ratio is shown as r = 0.093. The correlation of response AC/A ratio and relative accommodation showed as r = ?0.253, the CA/C ratio showed as r = 0.566 that is predictable correlation. The correlation of response AC/A ratio and CA/C ratio showed as r = ?0.355 that is low minus correlation (p = 0.000). The difference between a reciprocal response AC/A ratio and a CA/C ratio showed 0.12 ±0.06 D/? with a significant difference statistically (p=0.000).
Conclusions: The correlation of relative accommodation and CA/C ratio showed that depend on the individual, The more a relative accommodation is, the higher a response accommodation of convergence by convergence stimulus is. The reciprocal response AC/A and CA/C ratio showed significant differences statistically. This can have higher CA/C ratio in patients with low AC/A ratio in clinical as an independent variable. Thus when the abnormal binocular vision was prescribed in the clinical, it is necessary to consider the accommodative response even if the AC/A ratio is a normal range.
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KEYWORD
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Accommodative response, Convergence accommodation, Relative accommodation, Response AC/A ratio, CA/C ratio
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