高度近视眼准分子激光角膜前弹力层下磨镶术前后角膜生物力学变化的研究

摘要

目的 分析和探讨高度近视患者行准分子激光角膜前弹力层下磨镶术(SBK)前后角膜生物力学特性变化的特点。方法 前瞻性系列病例研究。高度近视患者36例（65眼），年龄19～34岁，平均(22.9±3.6)岁，等效球镜度-6.375～-12.50 D,平均(-8.35±1.21)D，所有患者均行SBK。术前和术后1个月，应用眼反应分析仪(ORA)对患者的模拟Goldmann眼压(IOPg)、角膜补偿眼压(IOPcc)、角膜阻力因子(CRF)、角膜滞后量(CH)及内向压平时间(TimeIn)和外向压平时间(TimeOut)进行测量和分析。应用配对t检验对手术前后IOPg 、IOPcc、CRF、CH、TimeIn、TimeOut和TimeOut-TimeIn变化进行对比分析，采用多重同归和Pearson相关分析影响角膜生物力学特性变化的因素。结果 术前I0Pg、IOPcc、CRF、CH和TimeIn、TimeOut及TimeOut-TimeIn分别为(17.5±3.0)mmHg、(17.6±2.9)mmHg、(11.1 ±1.4)mmHg、(10.5±1.3)mmHg、(8.0±0.4)ms、(18.6±0.2)ms和(10.7±0.4)ms，术后1个月分别为( 12.4 ±3.5) mmHg、(16.4±3.3)mmHg、(7.0±1.2)mmHg、(7.5±1.O)mmHg、(7.2±0.5)ms、( 18.4±0.2)ms和(11.2±0.5)ms。手术前后比较，差异均有显著统计学意义(t=14.2、3.5、28.1、24.9、17.4、16.2、-10.7,P均＜0.01)。△IOPg、△CRF与切削量(AD)呈正相关(r=0.247，P=0.047；r=0.298，P=O.O16)，而△IOPcc、△CH和△TimeIn、△TimeOut及△(TimeOut-TimeIn)与AD的相关性无统计学意义。结论 SBK矫正高度近视会对角膜生物力学产生一定的影响，使其术后角膜生物力学信号发生一系列变化，与激光切削量有一定的相关性。%Objective To analyze and investigate the influence of sub-Bowmann's keratomileusis (SBK) on corneal biomechanical properties in high myopia evaluated by the Goldmann correlated intraocular pressure (IOPg), corneal compensated IOP (IOPcc), corneal resistance factor (CRF), corneal hysteresis (CH), TimeIn, TimeOut and their changing values. Methods In this prospective case series study, there were 36 subjects (65 eyes) with high myopia underwent SBK. Their mean age was (22.9±3.6) years (ranged:19 to 34 years) and spherical equivalent was (-8.35±1.21)diopters (D) (range:-6.375 to -12.50 D). The IOPg, IOPcc, CR, CH, TimeIn and TimeOut were obtained with Ocular Response Analyzer (ORA) preoperatively and 1 month postoperatively. The values were analyzed before and after surgery using a paired t test. A multiple regression analysis and Pearson correlation were used to investigate the factors affecting the changing values. Results The mean preoperative values of IOPg, IOPcc, CRF, CH , TimeIn, TimeOut and the difference between TimeOut and TimeIn were (17.5±3.0)mmHg, (17.6±2.9)mmHg, (11.1±1.4)mmHg, (10.5±1.3)mmHg, (8.0±0.4)ms, (18.6±0.2)ms and (10.7±0.4)ms, respectively, and the mean values 1 month postoperative were (12.4±3.5)mmHg,(16.4±3.3)mmHg, (7.0±1.2)mmHg, (7.5±1.0)mmHg, (7.2±0.5)ms, (18.4±0.2)ms and(11.2±0.5)ms,respectively. The differences between preoperative and postoperative status were statistically significant (t=14.2, 3.5, 28.1, 24.9, 17.4, 16.2, -10.7, P＜0.01 for all). There was a trend toward positive correlation between ablation depth (AD) and △ IOPg (r=0.247, P=0.047), as well as between AD and △CRF (r=0.298, P=0.016); but no significant correlations were found between AD and other indices such as △IOPcc, △CH, △TimeIn, △TimeOut and the changing in the difference between TimeOut and TimeIn. Conclusion SBK for high myopia substantially weaken corneal properties and induce some changes in corneal biomechanical singnals, which are related to ablation depth to some extent.