目的:探讨近视眼二次LASIK手术病例临床特点、有效性和安全性。方法:回顾性系列病例研究。44例近视患者(72眼)接受二次LASIK,二次手术间隔时间为13.32±12.06(3～58)mo,二次LASIK术前平均残余屈光不正度为-2.56±1.56(-7.25～+1.13)D;分析年龄、屈光度、角膜中央厚度、角膜瓣厚度、残余角膜基质厚度的特点及其对残余屈光不正度的影响。结果:二次术后UCVA为0.89±0.19(0.5～1.2)μm,等效球镜度(SE)为0.05±0.57D。二次术前CCT为502.69±31.45μm,与理论残余的456.08±26.04μm差异有统计学显著性意义(t=-0.785,P=0.000);多元回归分析表明,在诸多因素中,术前预矫屈光度和切削深度对二次术前屈光度有显著性影响(F=73.442,P=0.000),回归方程:残余屈光不正度=-0.317+0.588×术前等效球镜+0.031×切削深度。结论:本组二次LASIK手术病例表明,预矫屈光度和切削深度是导致屈光回退的主要因素;术后角膜组织增生是LASIK远期屈光回退的机制之一;在严格控制角膜厚度和预矫屈光度的前提下,二次LASIK是安全、有效的。

AIM:To investigate the clinical effect and safety of laser in situ keratomileusis(LASIK) retreatment for correcting residual ametropia.METHODS:A retrospective study of 72 eyes of 44 cases who had a secondary LASIK procedure was carried out.After a mean follow-up of 13.32±12.06(3-58) months after the primary procedure,the mean myopic residual refraction was -2.56±1.56 diopters (D). The relation of age,center corenal thickness(CCT),corneal flap thickness and the residual stroma thickness of cornea with the residual ametropia were analyzed.RESULTS:The mean uncorrected visual acuity was 0.89± 0.19(0.5 to 1.2)μm,the mean spherical equivalent(SE) was 0.05±0.57D (P <0.05). The partner T test indicated that the CCT before the secondary LASIK,which was 502.69±31.54μm,was thicker than the theory residual CCT 456.08±26.04μm,and the difference was statistically sighificant(t=-0.785,P=0.000). Multivariate regression analysis indicated that the SE of preoperation and the depth of cut have prominence effect on the residual ametropia,the regression equation was residual ametropia =-0.317+0.588×SE+0.031×depth of cut.CONCLUSION:The SE and depth of cut seem to be the main factors for refractive regression. The corneal stroma proliferation is the main mechanism to refractive regression. Secondary LASIK is an effective and safe method to treat residual ametropia after primary LASIK for myopia.

R779.63