FS-LASIK联合快速角膜交联术矫正高度近视后角膜形态学及后表面高度变化

Postoperative Changes in Corneal Morphology and Posterior Corneal Elevation of High Myopia Corrected by Femtosecond LASIK Combined with Accelerated Corneal Cross-Linking

目的:探讨飞秒激光辅助准分子激光原位角膜磨镶术(FS-LASIK)联合快速角膜交联术(FS-LASIK Xtra)矫正高度近视后角膜形态学及后表面高度变化。方法:回顾性病例对照研究。连续纳入2020年7月到2022年4月在山东中医药大学附属眼科医院行FS-LASIK Xtra及单纯FS-LASIK的高度近视患者,其中FS-LASIK Xtra组46例(92眼),单纯FS-LASIK组41例(82眼)。收集患者术前和术后1、3、6个月的屈光度,利用Pentacam三维眼前节分析仪测量患者术前及术后1、3、6个月时角膜前表面平均曲率(Km)、中央区(角膜顶点)、旁中央区(以顶点为圆心直径2 mm的圆)和近周边区(以顶点为圆心直径4 mm的圆)角膜后表面高度(PCE),并记录术前屈光度、中央角膜厚度、术中切削深度。角膜后表面高度变化量(ΔPCE)为术后6个月时与术前高度的差值。采用独立样本t检验或Mann-Whitney U检验比较2组参数的组间差异,手术前后不同时间点PCE变化采用重复测量方差分析。结果:术前FS-LASIK组与FS-LASIK Xtra组Km分别为(43.40±1.11)D、(43.59±1.09)D,差异无统计学意义(P>0.05),术后各时间点2组Km稳定且2组间差异均无统计学意义(均P>0.05)。术前2组中央区、旁中央区和近周边区PCE比较差异均无统计学意义(均P>0.05);术后6个月时FS-LASIK组和FS-LASIK Xtra组中央区PCE分别为1.00(0,2.00)μm、0(-1.00,2.00),差异有统计学意义(Z=-2.31,P=0.021);术后3个月时FS-LASIK组和FS-LASIK Xtra组近周边区PCE分别为-1.00(-2.00,0)μm、-0.50(-1.25,0.50),差异有统计学意义(Z=-2.86,P=0.004),术后6个月时分别为-1.13(-2.00,0)μm、-0.25(-1.00,0.44),差异有统计学意义(Z=-2.74,P=0.006)。FS-LASIK组和FS-LASIK Xtra组术后中央区ΔPCE分别为-0.50(-2.00,1.00)μm、-1.00(-2.00,0)μm,差异有统计学意义(Z=-2.58,P=0.010),旁中央区ΔPCE分别为-0.25(-0.75,0.25)μm、-0.50(-1.25,0)μm,差异有统计学意义(Z=-2.96,P=0.003)。结论:FS-LASIK和FS-LASIK Xtra矫正高度近视术后中央区和旁中央区角膜后表面高度轻微后移,近周边区稍前凸,FS-LASIK Xtra术后3个月时变化较大并趋于稳定。在观察期内2种手术方式矫正高度近视安全且有效,联合快速交联术更有利于角膜后表面高度的稳定。

Objective:To investigate the alternation of corneal morphology and posterior corneal elevation after femtosecond laser-assisted laser in situ kerafomileusis(FS-LASIK)combined with accelerated corneal cross-linking surgery for the correction of high myopia.Methods:This was a retrospective case-control study.Patients with high myopia who received FS-LASIK Xtra or FS-LASIK alone in the Affiliated Eye Hospital of Shandong University of Traditiond Chinese Medicine from July 2020 to April 2022 were continuously enrolled in this study.Participants in this study included 46 patients(92 eyes)in the FS-LASIK Xtra group and 41 patients(82 eyes)in the FS-LASIK alone group.Diopter of patients before and 1,3 and 6 months after surgery was collected.Mean curvature(Km)and posterior corneal elevation(PCE)in the central area(corneal apex),paracentral area(the 2 mm circle with the apex as the center),and midperipheral area(the 4 mm circle with the apex as the center)were recorded before and 1,3 and 6 months after surgery.Preoperative refractive index,central corneal thickness,and intraoperative ablation depth were also recorded.The alternation of corneal posterior corneal elevation(ΔPCE)was the difference between the preoperative height and the postoperative height at 6 months.Independent sample t-test or Mann Whitney U-test were used to compare the differences between the two groups,the alternations of PCE at different time points before and after surgery were analyzed using repeated measures of variance.Results:The Km of the FS-LASIK group and the FS-LASIK Xtra group before surgery was 43.40±1.11 D and 43.59±1.09 D,respectively,with no statistically significant difference(P>0.05).The corneal curvature of the two groups was stable and no statistically significant difference(all P>0.05)at each time point after surgery.There was no statistically significant difference in the PCE between the two groups before surgery(all P>0.05).At 6 months after surgery,the PCE in the central region of the FS-LASIK group and FS-LASIK Xtra group were 1.00(0,2.00)μm and 0(-1.00,2.00)μm,showing a statistically significant difference(Z=-2.31,P=0.021).At 3 months after operation,the PCE in the near peripheral area of FS-LASIK group and FS-LASIK Xtra group was-1.00(-2.00,0)μm and-0.50(-1.25,0.50)μm,respectively,and the difference was statistically significant(Z=-2.86,P=0.004);at 6 months after surgery,the values were-1.13(-2.00,0)μm and-0.25(-1.00,0.44)μm,respectively,with statistical significance(Z=-2.74,P=0.006).The postoperativeΔPCE in the central region of the FS-LASIK group and FS-LASIK Xtra group were-0.50(-2.00,1.00)μm and-1.00(-2.00,0)μm,respectively,and the difference was statistically significant(Z=-2.58,P=0.010).And the postoperativeΔPCE in the paracentral region was-0.25(-0.75,0.25)μm and-0.50(-1.25,0)μm,respectively,with statistical significance(Z=-2.96,P=0.003).Conclusions:After FS-LASIK and FS-LASIK Xtra correction for high myopia,the posterior corneal elevation of the cornea in the central and paracentral regions slightly shifted back,and the near peripheral region slightly protruded.The FS-LASIK Xtra group showed significant alternations and tended to stabilize at 3 months after surgery.During the observation period,the two surgical methods for correcting high myopia are safe and effective,and the combination of accelerated corneal cross-linking is more conducive to the stability of the posterior corneal elevation.