摘要目的:采用标准矢量分析法分析飞秒激光制瓣准分子激光原位角膜磨镶术(FS-LASIK)对不同来源全眼散光的矫治效果,并对影响散光矫正效果的因素进行探讨.方法:回顾性系列病例研究.选取2012年6月至2013年6月在我院行FS-LASIK矫治近视和散光,术后6个月内随访资料完整的患者53例(106眼).根据角膜散光在全眼散光中所占的比例不同将患者分为角膜源性散光组(34眼),眼内源性散光组(36眼)和混合源性散光组(36眼).记录并比较3组术后6个月时的裸眼视力(UCVA)、UCVA≥术前最佳矫正视力(BCVA)的比例、角膜前表面形态变异指数(ISV)、垂直不对称指数(IVA)等指标.采用美国国家标准委员会推荐使用的标准矢量分析法对手术前后散光的相关指标进行运算和评估.采用单因素方差分析、卡方检验对数据进行分析.结果:术后6个月,3组间UCVA总体差异有统计学意义(F=4.80,P=0.013);角膜源性散光组、混合源性散光组的UCVA (P＜ 0.05),UCVA≥术前BCVA的比例(c2=7.48、5.21,P＜0.05)均大于眼内源性散光组,角膜源性散光组和混合源性散光组差异无统计学意义.角膜源性散光组术后残留散光最小,眼内源性散光组残留散光最大,2组差异有统计学意义(P=0.015),其余组间两两比较差异均无统计学意义.角膜源性散光组的矫正率(CR)均大于眼内源性散光组和混合源性散光组(P＜0.01),且手术引起的屈光矫正量的绝对值(|SIRC|)均大于眼内源性散光组、混合源性散光组(P＜ 0.01),眼内源性散光组和混合源性散光组差异无统计学意义.角膜源性散光组的角度误差(EA)、大小误差(EM)、误差率(ER)、矢量误差绝对值(|EV|)均小于眼内源性散光组、混合源性散光组,差异均有统计学意义(P＜0.01),且混合源性散光组的|EV|小于眼内源性散光组(P=0.030).角膜源性散光组的ISV、IVA均小于混合源性散光组(P＜0.01),混合源性散光组小于眼内源性散光组(P＜0.05).角膜源性散光组、眼内源性散光组、混合源性散光组平滑型角膜地形图比例分别为71％、39％、56％.结论:FS-LASIK矫正散光的效果取决于散光来源,对角膜源性散光的矫正效果最佳,对眼内源性散光的矫正效果最差.

abstractsObjective:To evaluate by standardized vector analysis the correction of different types of astigmatism after femtosecond laser-assisted in situ keratomileusis (FS-LASIK).Methods:In this retrospective case control study,106 myopic eyes of 53 cases from June 2012 to June 2013 at Shandong Province Guangming Eye Hospital with astigmatism were treated with FS-LASIK.The cases were divided into three groups according to the type of astigmatism:corneal (n=34),intraocular (n=36),and mixed (n=36).Uncorrected visual acuity (UCVA),proportion of UCVA higher than the preoperative best corrected visual acuity (BCVA),index of surface variance (ISV),index of vertical asymmetry (IVA),and the proportion of smooth cornea were measured six months postoperatively.The astigmatism status was evaluated based on standardized vector analysis.The data were analyzed by analysis of variance and Chi-squared tests.Results:Six months postoperatively,the UCVA differences among the three groups were significant (F=4.80,P=0.013).UCVA and the proportion of UCVA ≥ BCVA in the corneal astigmatism group and in the mixed astigmatism group were greater than in the intraocular astigmatism group (P ＜ 0.05 for each).The postoperative remaining uncorrected astigmatism of the corneal astigmatism group was the lowest,while that of the intraocular astigmatism group was the highest,and the difference between them was significant (P=0.015).The correction ratio (CR) in the corneal astigmatism group was higher than in the intraocular astigmatism and mixed astigmatism groups (P ＜ 0.01).The absolute surgically induced refractive correction (|SIRC|) of the corneal astigmatism group was higher than the intraocular astigmatism and mixed astigmatism groups (P＜ 0.01 each).Differences in CR and |SIRC| between the intraocular astigmatism and mixed astigmatism groups were not statistically significant.The error of angle,error of magnitude,error ratio,and absolute error vector (|EV|) of the comeal astigmatism group were lower than for the intraocular astigmatism and mixed astigmatism groups (P＜ 0.01 each).The |EV| of the mixed astigmatism group was lower than the intraocular astigmatism group (P=0.030).ISV and IVA of the corneal astigmatism group were lower than the mixed astigmatism group (P＜ 0.01 for both),and the ISV and IVA of the mixed astigmatism group were lower than the intraocular astigmatism group (P ＜ 0.05 for both).The proportions of smooth cornea of the corneal astigmatism,intraocular astigmatism,and mixed astigmatism groups were 71％,39％,and 56％.Conclusions:The efficacy of astigmatism correction after FS-LASIK is closely correlated with the type of astigmatism.Corrective efficacy was best for corneal astigmatism,and worst for intraocular astigmatism.