矢量分析法比较FS-LASIK矫正混合散光和远视散光的精准性和稳定性

Comparison of the Accuracy and Stability of FS-LASIK in the Correction of Mixed Astigmatism and Hyperopic Astigmatism by Vector Analysis

目的:采用标准化的矢量分析法观察和比较飞秒激光辅助的准分子激光原位角膜磨镶术(FS-LASIK)矫正混合散光和远视散光的精准性和稳定性。方法:回顾性非随机对照研究。选取2017年1月至2021年1月在河南省立眼科医院接受FS-LASIK矫正散光的患者41例(62眼),其中混合散光组21例(30眼),远视散光组20例(32眼)。分别于术前,术后1周、1个月、3个月和6个月对术眼进行视力、验光、裂隙灯显微镜、眼压及角膜地形图等检查。采用标准化的散光矢量分析法和报告屈光手术散光结果的国际标准图表对手术指标进行评价,包括等效球镜度(SE)、目标散光矢量(TIA)、手术引起的散光矢量(SIA)、误差的幅度(ME)、误差角度的绝对值(|AE|)、差异矢量的绝对值(|DV|)、矫正指数(CI)、成功指数(IOS)等指标。组间ME、|AE|、|DV|、CI、IOS和SE差异的比较采用Mann-Whitney检验,组间不同时间点|AE|、|DV|、ME、SE之间差异比较采用Kruskal-Wallis检验。结果:术后6个月时,混合散光组的|AE|和SE小于远视散光组,差异有统计学意义(Z=-2.02,P=0.043;Z=-2.77,P=0.006);混合散光组的ME为负值,CI值大于1,远视散光组的ME为正值,CI值小于1,组间ME和CI差异有统计学意义(Z=-4.93,P<0.001;Z=-4.28,P<0.001);组间|DV|差异无统计学意义。混合散光组术后6个月内各时间点|AE|之间差异无统计学意义,|DV|、ME、SE之间差异有统计学意义(H=15.98,P=0.001;H=10.54,P=0.014;H=10.90,P=0.012)。远视散光组术后6个月内各时间点|AE|、|DV|、ME之间差异无统计学意义,SE差异有统计学意义(H=10.11,P=0.018)。结论:术后6个月内,FS-LASIK矫正混合散光的精准性优于远视散光,矫正远视散光的稳定性优于混合散光,矫正混合散光时有过矫倾向,矫正远视散光时有欠矫倾向。

Objective:To investigate and compare the accuracy and stability of femtosecond-assisted laser in situ keratomileusis(FS-LASIK)in the correction of mixed astigmatism and hyperopic astigmatism by vector analysis.Methods:A retrospective and non-randomized controlled study was performed.Thirty mixed astigmatism eyes of 21 patients and 32 hyperopic astigmatism eyes of 20 patients underwent the FS-LASIK in Henan Eye Hospital were enrolled from January 2017 to January 2021.The visual acuity,refraction,slit-lamp microscopy,intraocular pressure and corneal topography were measured preoperatively and 1 week,1 month,3 months and 6 months postoperatively.Standardized astigmatism vector analysis and international standard for reporting astigmatism results of refractive surgery were used to evaluate the surgical indicators,including spherical equivalent(SE),target induced astigmatism vector(TIA),surgically induced astigmatism vector(SIA),magnitude of error(ME),absolute value of angle of error(|AE|),absolute value of difference vector(|DV|),correction index(CI)and index of success(IOS).The differences of ME,|AE|,|DV|,CI,IOS and SE between mixed astigmatism group and hyperopic astigmatism group were compared by Mann-Whitney test,and the differences between|AE|,|DV|,ME and SE at different time points between the groups were compared by Kruskal-Wallis test.Results:Six months postoperatively,AE and SE in mixed astigmatism group were less than those in hyperopic astigmatism group(Z=-2.02,P=0.043;Z=-2.77,P=0.006).The ME of mixed astigmatism group was negative,the CI value was greater than 1.The ME of hyperopic astigmatism group was positive,and the CI value was less than 1.The difference of ME and CI between the two groups was statistically significant(Z=-4.93,P<0.001;Z=-4.28,P<0.001).There was no significant difference in|DV|between the two groups.In the mixed astigmatism group,within 6 months postoperatively,there was no significant difference in|AE|on the whole,and there was significant difference in|DV|,ME,SE(H=15.98,P=0.001;H=10.54,P=0.014;H=10.90,P=0.012).In hyperopic astigmatism group,there was no significant difference in|AE|,|DV|,ME within 6 months postoperatively on the whole,and there was significant difference in SE(H=10.11,P=0.018).Conclusion:The accuracy of mixed astigmatism corrected by FS-LASIK are better than that of hyperopic astigmatism,the stability of correction of hyperopia astigmatism is better than that of mixed astigmatism,and it tends to be overcorrected in mixed astigmatism,while undercorrected in hyperopic astigmatism within 6 months postoperatively.