不透明气泡层在SMILE术中的产生及其与角膜生物力学相关影响因素的研究

摘要

目的 探讨飞秒激光小切口角膜基质透镜取出术(SMILE)术中不透明气泡层(OBL)的产生及其可能的生物力学影响因素进行分析.方法 巢式病例对照研究.入选2017年6至8月行SMILE的患者,术中出现OBL者为OBL组,与其同日行SMILE但无其他术中并发症者为无OBL组.通过术前Pentacam眼前节分析系统及CorvisST检查获取分析参数.独立样本t检验及多元Logistics回归模型分别用于分析两组之间生物力学参数的差异及与OBL发生可能相关的生物力学影响因素.结果 本研究共纳入71例(129只眼)患者,年龄为(22.50±5.18)岁,男性30例,女性41例,其中OBL组20例(31只眼),无OBL组51例(98只眼).结果 显示OBL组与无OBL组的等效球镜度数(SE)[(-4.64±1.33)和(-5.78±1.61)D]、中央角膜厚度(CCT)[(572±29)和(550±32) μm]、残余基质厚度(RST)[(356±31)和(325±36)μ m]及透镜厚度(LT)[(96±23)和(115±25) μm]差异均有统计学意义(t=3.58,-3.43,-5.68,3.64;P＜0.05);两组之间的第一次压平时的偏移幅度(A1 DefA)、最大压陷时的偏移幅度(HC DefA)、最大压陷时的偏移面积(HC DefArea)、最大形变幅度(DAmax)、最大偏移幅度(DefAmax)、角膜刚性参数(SP)(108.85±13.77和100.19±14.13)差异均有统计学意义(t=-2.75,2.41,3.62,4.09,2.22,-2.99;P＜0.05).Logistics回归基本模型和调整模型中,SP的OR值为1.04(95％可信区间1.01～ 1.07)(P=0.005)、1.01(95％可信区间1.00～1.05)(P=0.426).结论 影响OBL发生的角膜生物力学因素是多方面的,角膜厚度及残余基质床厚度较厚,SP较大均可能增加OBL发生的可能性.充分了解角膜生物力学特性对于手术效果的影响,同时评估术中OBL的发生,对于提高SMILE的安全性和预测性具有重要意义.%Objective To investigate the influence of corneal biomechanical properties on opaque bubble layer (OBL) in small incision lenticule extraction (SMILE).Methods In this nested case control study,20 patients (31 eyes) were enrolled in OBL group,while 51 patients (98 eyes) were included in non-OBL group.The parameters were obtained by Pentacam HR and Corvis ST examinations.Independent t test was used to analyze the difference of corneal biomechanical parameters between the two groups and multivariable logistics regression was applied to analysis the influence of corneal biomechanical properties on OBL.Results This study enrolled 129 eyes in 71 cases including 30 males and 41 females,with a mean age of (22.50±5.18) years old.It has shown that the spherical equivalent (SE) [(-4.64± 1.33) and (-5.78± 1.61) D],central corneal thickness (CCT) [(572±29) and (550t32)μm],residual stromal thickness (RST) [(356 ± 31) and (325± 36 μm)],and lenticule thickness (LT) [(96 ± 23) and (115± 25) μm] were significantly different between OBL group and non-OBL group (t=3.58,-3.43,-5.68 and 3.64,respectively,P＜0.05).There were significant differences in deflection amplitude at the first applanation and highest concavity (A1 DefA and HC DefA),deflection area at the highest concavity (HC DefArea),maximum deformation amplitude (DAmax),maximum deflection amplitude (DefAmax) and stiff parameter (SP) (108.85± 13.77 and 100.19± 14.13) between the two groups (t=-2.75,2.41,3.62,4.09,2.22 and-2.99,respectively,P＜0.05).The OR and 95％ confidence interval of SP in crude and adjusted logistics models were 1.04,(1.01-1.07) (P=0.005),and 1.01,(1.00-1.05) (P=0.426),respectively.Conclusions The occurrence of OBL could be influenced by various corneal biomechanical factors.The thicker CCT,thicker RST and the stiffer comea may increase the risk for the occurrence of OBL.Fully acknowledgement on the relationship between corneal biomechanics and surgical outcomes and evaluation of the occurrence of OBL in SMILE surgery is of great importance for improving the safety and predictability of SMILE.