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KMID : 1159320130150010019
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Korean Journal of Vision Science
2013 Volume.15 No. 1 p.19 ~ p.27
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Correlation between N.P.A. and N.P.C. in Emmetropia and Myopia
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Jeong Keun-Seung
Ryu Geun-Chang
Jun Jin
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Abstract
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Purpose: To investigate the correlation bwtween N.P.A.(Near Point of Accommodation) andN.P.C(Near point of Convergence) in emmetropia and myopia.Methods: To analyze the correlation between the N.P.A and N.P.C., wc targeted 323 highschlool students who don`t have any ophthalmic or systemic disease and having over 1.0 corrected vision. Also they turned out to be nomal in all preliminary test.Results : The correlation between N.P.A. and N.P.C. in myopia was lower compared to emmetropia. It was also analyzed that the correlation was lower in both myopia of astigmatism against the rule and with the oblique compared to the simple myopia and myopis of astigmatism with the rule.Conclusion: Weassume that the reason of low relationship bwtween N.P.A. and N.P.C. in myopia comepared to emmetrooia is because of different change ratio bwtween an amplitude of accommodation and an angle of convergence. The reason of this phenomenon is explained by the accommodation effect and the prism effect of the lens when we have to focus on the near point.
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KEYWORD
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Near point of accommodation, Near point of convergence, Convergence angle, Accommodation effect, Prism effect
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