摘要背景 准分子激光角膜屈光手术因术后痛苦小、视力恢复快、有效性佳和预测性好,成为目前治疗屈光不正的主流方法,但术后角膜生物力学性能降低可导致继发圆锥角膜、角膜扩张等并发症,因此准分子激光角膜屈光术后角膜生物力学的研究是临床上受到关注的问题之一. 目的 研究不同准分子激光角膜屈光手术对角膜生物力学的影响.方法 采用前瞻性非随机对照的研究方法,纳入拟行角膜屈光手术的中度近视患者82例164眼,按手术方式的不同将患者分为前弹力层下激光角膜磨镶术(SBK)组(30例60眼)、准分子激光角膜原位磨镶术(LASIK)组(27例54眼)和准分子激光上皮下角膜磨镶术(LASEK)组(25例50眼),3个组受检者基线特征均相匹配.利用眼反应分析仪(ORA)分别测定和比较不同手术方式组术眼术前及术后1周和5个月的角膜滞后量(CH)值和角膜阻力因子(CRF)值,并分析角膜切削厚度与CH、CRF手术前后差值的关系. 结果 不同时间点SBK、LASIK、LASEK组间CH和CRF的总体比较差异均无统计学意义(F分组=2.17,P=0.08;F分组=2.67,P=0.07),各组不同时间点间CH值和CRF值的总体比较差异均有统计学意义(F时间=41.90,P=0.00;F时间=49.65,P=0.00),3个组术后1周、5个月,CH、CRF值均较术前明显下降,差异均有统计学意义(均P=0.00).对角膜切削厚度与CH、CRF的差值分析发现,术后1周至术后5个月,角膜切削厚度与CH差值均不相关(均R2=0.000),但与CRF差值呈弱相关(1周:Y=3.253+0.010X,R2=0.007;5个月:Y=1.073+0.021 R2,R2=0.004). 结论 SBK、LASIK、LASEK术后术眼的角膜CH和CRF值均下降,导致角膜的生物力学变化,3种手术方式对角膜生物力学的影响相似,CRF在评价角膜屈光手术后角膜生物力学变化方面比CH更有价值.

abstractsBackground Refractive surgery has propelled itself forward to become widely performed surgical procedure nowadays.After the surgery,corneal biomechanics decreases lead to keratoconus and corneal ectasia.Doctors pay more attention to biomechanics changes after refractive surgeries.Objective This clinical study was to investigate the influence of different laser refractive surgeries on corneal biomechanics.Methods A prospective nonrandomized and controlled clinical study was designed.One hundred and sixty-four eyes of 82 patients with moderate myopia were enrolled.The patients were divided into sub-Bowman keratomileusis (SBK) group (60 eyes of 30 patients),laser in situ keratomileusis (LASIK) group (54 eyes of 27 patients) and laser subepithelial keratomileusis (LASEK) group (50 eyes of 25 patients),with the matched demography among the three groups.Corneal hysteresis (CH) and corneal resistance factor (CRF) were detected by ocular response analyzer (ORA) before and 1 week,5 months after refractive surgery.The correlations between stromal ablation depth and postoperative changing values of CH or CRF were analyzed.Results Significant differences were found in CH and CRF at different time points in the three groups (Ftime =41.90,P =0.00;Ftime =49.65,P =0.00),and the CH and CRF values were significantly lower 1 week and 5 months after surgery than those before surgery (all at P =0.00).However,no significant difference of CH or CRF was seen at all time points among the three groups (Fgroup =2.17,P =0.08;Fsroup =2.67,P =0.07).No correlation was found between corneal ablation depth and CH in 1 week and 5 months after surgery (both at R2 =0.000),however,weaker correlations were seen between corneal ablation depth and CRF 1 week and5 months after surgery (Y=3.253+ 0.010X,R2=0.007;Y=1.073+0.021 X,R2=0.004).Conclusions SBK,LASIK and LASEK lead to the change of corneal biomechanics by altering CH and CRF,they play the same influence on cornea.CRF appears to be an useful indicator in evaluating corneal biomechanical changes after laser refractive surgery.