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목적 : To investigate the contribution of posterior corneal astigmatism to total ocular astigmatism and the errors in estimating total corneal astigmatism from anterior corneal measurements only using the dual-Scheimpflug analyzer.
방법 : 200 eyes out of 100 consecutive healthy subjects were included at the Asan Medical Center between December of 2013 and February of 2014. Total ocular astigmatism was measured by subjective refraction. Total corneal astigmatism was calculated using ray tracing and anterior corneal astigmatism, and the posterior corneal astigmatism was done using the dual-Scheimpflug analyzer (Galilei,Zimmer, Switzerland) . Their changes with age were analyzed.
결과 : The mean total ocular astigmatism was 1.041±1.065 diopter(D) and posterior corneal astigmatism was -0.483±0.872 D. The steep corneal axis was vertically aligned (60 to 120 degree) in 50.8% of eyes in the anterior cornea and in 88.3% in the posterior cornea. As the age increased, the steep anterior corneal axis tended to change from vertical to horizontal, while the steep posterior corneal axis did not.
결론 : Posterior corneal astigmatism contributed to total ocular astigmatism especially in Korean eyes, which could cause incorrect estimation of total ocular astigmatism when selecting toric intraocular lenses. Measuring the posterior corneal astigmatism as well as anterior corneal astigmatism could be important in Korean eyes.
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