2 mm与4 mm切口SMILE术后视觉效果对比

目的探讨行2 mm与4 mm切口的飞秒激光小切口角膜基质透镜取出术（SMILE）患者术后的视力、屈光度、高阶像差和角膜地形图的变化。方法前瞻性对照研究。接受SMILE手术矫正近视和近视散光的患者34例（68眼），按手术中切口大小分成2 mm切口组（44眼）和4 mm切口组（24眼）。分别测量并记录患者术前，术后1周，术后1、3、6个月的裸眼远视力（UCVA）、最佳矫正视力（BCVA）、屈光度、总高阶像差（HOAs）、球差（Z40）、垂直彗差（Z3-1）、水平彗差（Z31）、角膜前表面散光、角膜不规则指数（CIM）和形状因子（SF）等。应用重复测量方差分析比较2组之间手术前后各参数的差异。结果2组之间各个时间点的UCVA、BCVA和屈光度差异均无统计学意义。术后1周时，4 mm切口组的Z3-1较2 mm切口组大（t=-2.031，P＜0.05）；术后1周和1个月时，4 mm切口组的角膜前表面散光较2 mm切口组高（t=-2.126、-2.108，P＜0.05）；术后1周和1个月时，4 mm切口组的CIM较2 mm切口组大（t=-2.360、-2.395，P＜0.05）。结论在角膜前表面散光、Z3-1和CIM方面，2 mm切口的SMILE比4 mm切口的SMILE更有优势。

Effects of a 2 mm versus 4 mm incision width on visual outcomes after SMILE

Objective To evaluate the effects of incision width on visual outcomes by comparing visual acuity,refractive error,higher-order aberrations and corneal topography parameters after femtosecond small-incision lenticule extraction (SMILE).Methods This was a prospective case-control study.Thirty-four patients (68 eyes) who underwent SMILE to correct myopia and myopic astigmatism were included.We divided them into two groups by a side cut of 2 mm or 4 mm.Twenty-two patients (44 eyes) were in the 2 mm side-cut group while 12 patients (24 eyes) were in the 4 mm side-cut group.All patients underwent routine examinations before the surgery in case of surgical contraindications.Preoperatively and 1 week and 1,3 and 6 months postoperatively,we measured UCVA,BCVA,refractive error,total higher-order aberrations (HOAs),spherical aberrations (Z40),vertical coma (Z3-1),horizontal coma (Z31),anterior corneal surface astigmatism,corneal irregularity measurement (CIM) and shape factor (SF).A repeated measures analysis of variance was used to compare the differences in these data between the two groups and between pre-and post-operation.Results No differences were found in UCVA,BCVA or refractive error between the two groups at any time point.For Z3-1,the outcomes in the 4 mm side-cut group were higher than in the 2 mm side-cut group at I week postoperatively (t=-2.031,P＜0.05).For anterior corneal surface astigmatism,the outcomes in the 4 mm side-cut group were higher than in the 2 mm side-cut group at 1 week and 1 month postoperatively (t=-2.126,-2.108,P＜0.05).For CIM,the outcomes in the 4 mm side-cut group were higher than in the 2 mm side-cut group at 1 week and 1 month postoperatively (t=-2.360,-2.395,P＜0.05).Conclusion When considering Z3-1,anterior corneal surface astigmatism and CIM,SMILE with a 2 mm side cut has advantages over SMILE with a 4 mm side cut.