Sirius眼前节分析仪测量飞秒激光制瓣LASIK术后角膜后表面的变化

The changes in posterior corneal curvature measured by Sirius topography in post-femtosecond LASIK patients

目的：使用Sirius眼前节分析仪测量飞秒激光制瓣LASIK术后角膜后表面形态，并分析其影响因素。方法前瞻性非随机临床研究。73例（146眼）近视患者纳入本研究。其中，男35例，女38例。年龄19-36岁，平均（25.7±5.1）岁。等效球镜度（SE）-10.25--4.50 D，平均（-6.95±1.97）D。使用Sirius眼前节分析仪测量术前及术后1个月3、5、7 mm区域角膜后表面曲率。将术后1个月角膜后表面曲率变化值（ΔK）与切削百分比（AD/CT）、切削深度（AD）、残留基质厚度（RBT）及SE进行Pearson相关分析，并进一步采用逐步回归法对ΔK的影响因素行多元线性回归分析。结果术后1个月，3、5 mm直径区域角膜后表面曲率均比术前增加，差异有统计学意义（t=3.58、3.36，P〈0.01）。ΔK3 mm、ΔK5 mm、ΔK7 mm与AD/CT（r=0.845、0.833、0.753，P〈0.01）和AD（r=0.725、0.727、0.603，P〈0.05）呈正相关，而与SE （r=-0.762、-0.756、-0.674，P〈0.05）和RBT（r=-0.784、-0.733、-0.864，P〈0.01）呈负相关。多元线性回归分析发现AD/CT、RBT为ΔK3 mm的影响因素（β=2.048、-0.002，95%CI：0.489-3.607、-0.003-0，P〈0.1）；AD/CT 为ΔK5 mm的影响因素（β=2.005，95%CI：1.068-3.942，P〈0.1）；RBT、SE 为ΔK7 mm的影响因素（β=-0.003、-0.325，95%CI：-0.004-0.002、-0.786-0.428，P〈0.1）。结论飞秒激光制瓣LASIK术后角膜后表面微量前凸，在保证手术效果的前提下，控制切削比，保留足量残留基质厚度，可以尽量避免术后角膜扩张、屈光回退等并发症的发生。

Objective To investigate changes in posterior corneal curvature （ΔK ） in post-femtosecond LASIK patients using Sirius topography, and to analyze its relationship with ablation percentage （AD/CT） and depth （AD）, residual bed thickness RBT, and spherical equivalent （SE）. Methods This was a prospective nonrandomized study. Seventy-three post-femtosecond LASIK patients were recruited for this study （146 eyes; aged 19 to 36 years, mean 25.7±5.1 years; spherical equivalent-10.25 to -4.50 D, mean -6.95±1.97 D）. Posterior corneal curvature was measured by Sirius topography pre-surgery and at 1 month post-surgery. The correlations between ΔK and AD/CT, AD, RBT, and SE were analyzed. Results One month post-surgery, the posterior corneal curvatures of the 3 mm and 5 mm diameter range were higher than those for pre-surgery （t=3.58, 3.36; P〈0.01）. Univariate regression analyses showed that the ΔK3 mm, ΔK5 mm, and ΔK7 mm were positively correlated with their AD/CT （r=0.845, 0.833, 0.753; P〈0.01） and AD （r=0.725, 0.727, 0.603; P〈0.05）. The ΔK3 mm, ΔK5 mm, and ΔK7 mm were negatively correlated with the SE （r=-0.762, -0.756, -0.674; P〈0.05） and RBT （r=-0.784, -0.733, -0.864; P〈0.01）. A stepwise multiple linear analysis was used to determine the factors associated with ΔK . AD/CT and RBT were the factors that influenced ΔK3 mm （β=2 . 048 ,-0.002; 95%CI： 0.489-3.607, -0.003-0; P〈0.1）; AD/CT was the factor that influenced ΔK5 mm （β=2.005; 95%CI： 1.068-3.942; P〈0.1）; RBT and SE were the factors that influenced ΔK7 mm （β=-0.003, -0.325; 95%CI： -0.004-0.002, -0.786-0.428; P〈0.1）. Conclusion This research shows that the corneal posterior surface has a slightly forward shift in post-femtosecond LASIK patients. TheΔK is related to ablation percentage and depth, spherical equivalent, and residual bed thickness.