手术前后Orbscan Ⅱ系统测量误差的分析与校正

目的 探讨orbscan Ⅱ的测量误差及其影响因素，为临床使用提供可靠依据。方法 测量lasik 113例226眼及lasek 14例27眼，使用orbscan Ⅱ系统和A超角膜测厚仪，分别于手术前及手术后1月测量角膜厚度、角膜曲率及角膜后表面屈光力。并对测量值进行分析。结果 lasik组和lasek组，Orbscan Ⅱ术前测量的角膜厚度均较A超值高，而术后均较A超值低；术后lasik组和lasek组的角膜后表面屈光力较术前均有增加.结论 Orbscan Ⅱ测量的准确性较高，但对于角膜较薄的患眼，要进行测量误差的校正。

The analysis and correction of orbscan Ⅱ topography system's testing disorder

ObjectiveTo discuss the measurement error and t he influence factor of Orbscan topography to provide more accurate data for clin ical application.MethodsOrbscan topography system and A-scan ultrasonography w ere used to measure the corneal thickness and the curvature of posterior corneal surface.Including 113 cases (226 eyes) undergoing laser in situ keratomileusis (Lasik) and 14 cases (27eyes) undergoing laser epithelial keratomileusis (Lasek) before and after the operations.And the result of measurement was compared.Resultspre-operatively,the value of corneal thickness was low er measured by A-scan ultraconography than by orbscan topography.And post-oper atively the value was lower than that by orbscan topography.The value of posteri or corneal surface curvature after lasik and lasek was more than before.ConclusionThe values obtained by Orbscan topography were accur acy,but there were necessary to improve the accuracy of orbscan topography syste m when we measured the thicker cornea.