Orbscan-Ⅱ评估LASIK术后角膜后表面曲率变化的研究  

Assessment of posterior curvature of myopia eyes with OrbscanⅡ after LASIK

作　　者：庄文娟[1,2] 纳莉[1] 李自立[1] 梅惠香[1] 杨默迟[1] 

机构地区：[1]宁夏医科大学附属医院眼科,银川750004 [2]重庆医科大学,在读博士研究生400016

出　　处：《眼科研究》2010年第5期467-470,共4页Chinese Ophthalmic Research

基　　金：宁夏回族自治区卫生厅科研项目(2008038)

摘　　要：目的采用Orbscan-Ⅱ测量方法对LASIK术后患者角膜后表面曲率的变化进行评估。方法 Orbscan-Ⅱ测量95例189眼LASIK术眼手术前后角膜后表面的曲率参数,高斯光学公式计算角膜后表面屈光力,对手术前后角膜后表面曲率半径和屈光力的比较采用配对t检验进行统计学分析,Bland-Altman用于其一致性和可重复性的评估。结果手术前后角膜平均曲率半径分别为(6.42±0.23)mm和(6.32±0.24)mm,即LASIK术后角膜曲率半径较术前下降,差异有统计学意义(P<0.01),角膜后表面屈光力手术前后分别为(-6.24±0.22)D和(-6.33±0.24)D,差异有统计学意义(P<0.01)。LASIK手术前后角膜后表面屈光力的差异值与矫正近视量呈正相关(r=0.326,P=0.0004)。Bland-Altman显示手术前后角膜后表面曲率半径的一致性界限为(-0.118mm,0.31mm),角膜后表面屈光力的一致性界限为(-0.116D,0.308D)。结论 Orbscan-Ⅱ可用于LASIK术后角膜后表面曲率半径的测定,联合高斯光学公式计算角膜后表面屈光力对于LASIK术后人工晶状体计算的评估是可行的。Background Inaccurate postoperative refraction after cataract has been reported in patients who have undergone corneal refractive operation. Such suboptimal refractive outcomes may partly be explained by the inaccuracy of standard keratometry in estimating the net corneal refractive power. Therefore this is a new challenge which ophthalmologist should face about how to assess the posterior corneal power correctly after LASIK. Objective The aim of this study was to evaluate the difference of posterior corneal curvature in patients undergoing myopic LASIK using Orbscan Ⅱ measurements. Methods The parameters of the posterior corneal curvature were detected with Orbscan Ⅱ in 189 eyes underwent myopic LASIK. Corneal refractive power was calculated using the Gaussian optic formula. The posterior corneal curvature radius and corneal refractive power between pre-LASIK and post-LASIK were compared using the paired sample t-test. Bland and Altman plot was used to estimate the repeatability and reliability of Orbscan Ⅱ measuring technique. Results The mean pre-and postoperative radius of posterior corneal curvature were （ 6.42 ± 0. 23 ） mm and （ 6.32±0. 24） mm respectively, showing a statistically significant decline after LASIK （ P 〈 0.01 ）. The mean posterior corneal power values in pre-LASIK and post-LASIK were （ - 6.24 ±0. 22） D and （ -6.33 ±0.24）D respectively and the difference was statistically significant（P 〈 0.01 ）. The difference value of posterior corneal curvature between pre-and post-LASIK showed a positive correlation with the amount of myopic correction（ r = 0. 326 ,P = 0. 000）. Bland and Altman plot in pre-and post-operative posterior corneal curvature revealed that the agreement limits of radius of posterior corneal curvature was from 0.31 mm to - 0. 118 mm and that of posterior corneal power was from 0. 308 D to -0. 116 D. Conclusion Orbscan Ⅱ can be used to measure the posterior corneal curvature in patients with myopic LASIK. It is feasible for the assessment

关 键 词：准分子激光原位角膜磨镶术 角膜后表面屈光力 Orbscan-Ⅱ 高斯光学公式 

分 类 号：R779.63[医药卫生—眼科]