马来酸噻吗洛尔滴眼液预防高度近视眼LASIK术后屈光回退的随机对照研究

The randomized controlled study on timolol preventing refractive regression after LASIK in high myopic eyes

背景 屈光回退是高度近视眼准分子激光角膜原位磨镶术（LASIK）术后较常见的并发症,影响手术的长期稳定性.目前尚无预防LASIK术后屈光回退的方法. 目的 观察马来酸噻吗洛尔滴眼液对高度近视眼LASIK术后屈光回退的预防效应.方法 采用前瞻性干预性临床随机对照研究.选取2012年2-9月在遵义医学院附属医院行LASIK的高度近视患者60例60眼,屈光度为（-7.16±0.95）D.将患者按随机数字表法分成试验组和对照组,2个组患者术后均给予常规抗炎用药,试验组患者在术后第1天开始滴加质量分数0.5％马来酸噻吗洛尔滴眼液,每日2次,1个月后改为每天晨起点眼1次.测量2个组患者术前,术后1周及1、3、6个月的裸眼视力、最佳矫正视力（BCVA）、等效球镜度（SE）、角膜前表面曲率和眼压,并测量术前及术后1、3、6个月术眼的中央角膜厚度（CCT）,术前测算残余角膜基质厚度.采用重复测量方差分析、独立样本t检验和Bonferroni检验对2个组在不同时间点间的数据进行分析. 结果 试验组及对照组间患者术前的年龄、裸眼视力、BCVA、SE、眼压、角膜前表面曲率、CCT及残余角膜基质厚度的差异均无统计学意义（P＞0.05）.2个组间手术后不同时间点的裸眼视力差异有统计学意义（F分组=3.91,P＜0.05；F时间=3.80,P＜0.05）,其中术后6个月试验组裸眼视力优于对照组（t=2.97,P＜0.05）,试验组术后6个月裸眼视力优于术后7d,差异有统计学意义（P＜0.05）.2个组术眼在术后不同时间点BCVA的差异无统计学意义（F分组=2.44,P＞0.05；F时间 =2.31,P＞0.05）.2个组间术眼术后SE的有统计学意义（F分组=11.52,P＜0.05）,术后不同时间点术眼SE的整体比较差异有统计学意义（F时间=22.06,P＜0.05）,术后6个月试验组术眼SE高于对照组（t=2.47,P＜0.05）,术后7d及术后1个月、3个月试验组术眼的校正眼压明显低于对照组（F分组=14.83,P＜0.05）,术后2个组间CCT的增幅差异无统计学意义（F分组=0.04,P＞0.05）.术后试验组角膜前表面曲率变化平稳,但对照组随着时间的延长角膜前表面曲率逐步增加（F时间=18.73,P＜0.05）.结论 高度近视眼LASIK术后早期局部使用0.5％马来酸噻吗洛尔滴眼液能减少屈光回退,提示0.5％马来酸噻吗洛尔滴眼液通过降低眼压而阻止角膜膨隆,其可能是预防术后屈光回退的主要机制.

Background Refractive regression is a common complication of high myopia after laser in situ keratomileusis （LASIK）,and it affects the stability of surgery.Objective This study was to observe the preventive effect of timolol on refractive regression in high myopia after LASIK.Methods A perspective randomized controlled trial was performed under the approval of Affiliated Hospital of Zunyi Medical College and the informed consent of the patients.Sixty eyes of 60 patients with high myopia （-7.16±0.95） D for LASIK were randomized into experimental group and control group.Regular eye drops were topically administered in the patients after LASIK in both groups,and timolol 0.5 ％ was added topically from 1 day after LASIK.The uncorrected visual acuity （UCVA）,best corrected visual acuity （BCVA）,spherical equivalent （SE）,corneal anterior surface curvature,intraocular pressure （IOP）,central corneal thickness （CCT） were measured before LASIK,1 week,1 month,3 months and 6 months after LASIK,respectively.Residual stromal bed thickness was calculated before LASIK.The differences of above-mentioned indexes were analyzed and compared between the two groups and among the various time points using repetitive measurements analysis of variance,independent simple t test and Bonferroni test.Results No significant differences were found in the demography between the experimental group and the control group,including age,UCVA,BCVA,SE,IOP,corneal anterior surface curvature,CCT and residual stromal bed thickness （all at P＞0.05）.UCVA was significantly different between the two groups among various time points （Fgroup =3.91,P＜0.05 ; Ftime =3.80,P＜0.05）,and the UCVA was significantly higher in the experimental group than the control group 6 months after LASIK （t=2.97,P＜0.05）,and UCVA was gradually increased as the lapse of postoperative time with the significant difference between 7 days and 6 months after LASIK in the experimental group （P＜0.05）.No significant difference was seen in the BCVA between the two groups at various postoperative time points （Fgroup =2.44,P＞0.05;Ftime =2.31,P＞0.05）.SE refraction in both groups were significantly reduced from 7 days through 6 months after LASIK,showing significant difference between the groups at various time points after LASIK（Fgroup =11.52,P＜0.05;Ftime =22.06,P＜0.05）.The SE refraction was higher in the experimental group than that in the control group 6 months after LASIK （t =2.47,P＜0.05）.Corrected IOP in the experimental group was lower than that of the control group at 7 days,1 month and 3 months after LASIK,respectively （Fgroup =14.83,P＜0.05）.The change of CCT was not statistically different between the control group and the experimental group （Fgroup =0.04,P＞0.05）.The anterior corneal surface curvature was steady in the experimental group during the following-up duration after LASIK,while the control group was growing gradually （Ftime =18.73,P＜0.05）.Conclusions The study data show that topical administration of 0.5％ timolol early in high myopia following LASIK is effective for the reduction of the refractive regression.It is suggested that 0.5％ timolol can prevent cornea ectasia by lowering IOP.Reduction of the IOP may contribute to improving the regression after keratorefractive surgery in high myopic eyes.