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목적 : to compare ray tracing method and Gaussian optic formula for postoperative keratometry measurement after myopic photorefractive keratectomy.
방법 : The manifest refraction and Pentacam (Oculus Inc.) analyses were measured preoperatively and 6 month postoperative after myopic photorefractive keratectomy (PRK) (STAR S4 IR CustomVue, Abbott Medical Optics/Visx) in 59 eyes from 30 patients (age 25.42 ± 3.51 years, mean±SD). The refractive change at corneal plan was compared with keratometric changes including simulated keratometry (simK), true net power (TNP), total corneal refractive power (TCRP) at center, 1mm, 3mm and 4mm.
결과 : Postoperative change of SimK showed the largest difference and postoperative change of TCRP at 4mm showed the smallest difference when compared to refractive change at corneal plane. The 95% limit of agreement (LoA) between refractive changes at corneal plane and the changes of TCRP at 4 mm was -0.85 to 1.31 diopters. TCRP at 4 mm predicted the refractive change at cornea plane within 1.0D in 100% and within 0.5D in 91.5% of study eyes. TCRP at 4 mm showed the closest correlation with refractive change. (r=0.963, p<0.001)
결론 : Ray tracing method (TCRP) showed superior performance in corneal power measurement after myopic PRK compared to Gaussian optic formula (TNP).
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