目的:探讨飞秒激光小切口角膜基质透镜取出术（SMILE）后角膜生物力学特性变化量随残余基质厚度（RST）、组织去除厚度百分比（PTA）的变化规律，并分析SMILE后角膜生物力学特性的影响因素。方法:回顾性系列病例研究。选取2019年1月至2020年1月于天津市眼科医院屈光手术中心行SMILE者184例（184只右眼），其中男性83例，女性101例，年龄（24.6±5.8）岁。于术前和术后3个月用Corvis ST角膜生物力学分析仪测量术眼的角膜生物力学参数，包括形变幅度比值（DA ratio）、角膜硬度参数（SPA1）和综合半径（IR）。对RST、PAT与DA ratio、SPA1、IR的变化量的关系进行线性和非线性回归分析。纳入年龄、性别、角膜前表面平均曲率（Km）、术前等效球镜度数（SE）、术后角膜中央厚度（CCT）和术前角膜生物力学参数为自变量，采用步进法多元线性回归模型分析术后DA ratio、SPA1和IR的影响因素。对手术前后数据比较采用配对n t检验；相关性检验采用Pearson或Spearman相关性分析。n 结果:SMILE术后DA ratio、SPA1和IR的变化量（变化率）分别为1.33（30.0%）、28.05（26.0%）和2.56（34.0%），手术前后差异均具有统计学意义（n t=35.52， -28.00， 36.95；n P<0.01）。最优拟合曲线显示，随着RST减少或者PTA的增加，DA ratio、SPA1和IR的变化量逐渐升高。其中，当RST28%时，DA ratio变化量曲线斜率明显增加。多因素回归模型显示，对SMILE术后DA ratio、SPA1和IR根据标准化回归系数（Sβ值）排序，影响权重前3位的因素分别为术前DA ratio（Sβ=0.489）、术前SPA1（Sβ=0.483）和术前IR（Sβ=0.471）；CCT是术后DA ratio和SPA1的第二大影响因素（Sβ=-0.238，0.326）。n 结论:SMILE术后DA ratio、SPA1和IR的改变随RST的减少或者PTA的增加而增加，当RST28%时，DA ratio的改变速度明显加快；术前角膜生物力学特性和术后CCT是影响术后角膜生物力学稳定性的主要因素。n （中华眼科杂志，2021，57：104-112）“,”Objective:To explore the rule of corneal biomechanical alteration with residual stromal thickness (RST) and percent tissue altered (PTA) after small incision lenticule extraction (SMILE) and to determine the factors influencing postoperative corneal biomechanical properties.Methods:In this retrospective study, a total of 184 patients (184 right eyes) who underwent SMILE in Tianjin Eye Hospital Refractive Surgery Center from January 2019 to January 2020 were enrolled. There were 83 males and 101 females with age of (24.6±5.8) years. Corneal biomechanical parameters, including DA ratio, stiffness parameter at the first applanation (SPA1) and integrated radius (IR), were measured with Corvis ST preoperatively and at 3 months postoperatively. The association between PTA, RST and the changes of DA ratio, SPA1 and IR was assessed by linear and nonlinear regression analyses. Stepwise multivariate regression analyses were conducted to explore the factors associated with postoperative corneal biomechanical parameters with age, sex, anterior mean keratometry, spherical equivalent, postoperative central corneal thickness (CCT) and preoperative corneal biomechanical parameters as covariates. Preoperative and postoperative data were compared using the paired n t test. Correlations were determined by the Pearson or Spearman analysis.n Results:The alterations at 3 months postoperatively of DA ratio, SPA1 and IR were 1.33 (30.0%), 28.05 (26.0%) and 2.56 (34.0%), respectively. The changes before and after surgery were statistically significant (n t=35.52, -28.00, 36.95, n P<0.01). The best-fit curve showed that the changes of DA ratio, SPA1 and IR increased with the decrease of RST or increase of PTA. When the RST was28%, the slope of the change of DA ratio curve was significantly increased. Multivariate regression models showed that the factors with the greatest influence on postoperative DA ratio, SPA1 and IR were preoperative DA ratio (Sβ=0.489,n P<0.01), preoperative SPA1 (Sβ=0.483,n P<0.01) and preoperative IR (Sβ=0.471,n P<0.01), respectively. The CCT was the second factor that influenced postoperative DA ratio and SPA1 (Sβ=-0.238,n P<0.01; Sβ=0.326,n P<0.01).n Conclusions:The changes of DA ratio, SPA1 and IR following SMILE increased with the decrease of RST or increase of PTA. With the RST28%, the alteration of DA ratio significantly accelerated. Preoperative corneal biomechanical properties and postoperative CCT were main factors influencing corneal biomechanical properties after SMILE.n (Chin J Ophthalmol, 2021, 57: 104-112)