Analysis on the efficacy of SBK surgery for myopia and astigmatism performed by Winsight excimer laser ablation

Objective To evaluate the efficacy of sub-Bowman's keratomileusis (SBK) surgery performed by Winsight excimer laser ablation for the treatment of myopia,to evaluate the predictability,safety and quality of vision using this procedure.Methods This was a retrospective case-control study.One hundred fifty-six eyes of 78 cases that had undergone SBK for myopia were analyzed retrospectively.Half of the eyes were treated with Winsight and half with Allegretto Eye-Q.Primary outcome variables,including uncorrected visual acuity (UCVA),best corrected visual acuity (BCVA),and manifest refraction spherical equivalent (SE),were evaluated at 1 week and 1,3 and 6 months postoperatively.Dark room and dark room glare contrast sensitivity were evaluated at 1,3 and 6 months postoperatively in the test group.Data were analyzed using independent t test and ANOVA.Results There were no significant differences in postoperative UCVA and SE between the test and control groups.At 1,3 and 6 months,the respective proportions of eyes achieving postoperative SE within ±0.5 D were 97％,97％ and 97％ for the test group and 96％,99％ and 99％ for the control group.UCVA was 5.0 or better in 100％,100％ and 99％ of eyes in the test group.At 1,3 and 6 months postoperatively,the mean efficacy index was 1.01±0.01 for both the test and control groups (t=1.551,0.796,1.662,P＞0.05).In the test group,no eyes had lost more than 2 lines of BCVA at 1,3 and 6 months postoperatively.The mean safety indices were 1.02±0.01,1.01±0.01 and 1.01±0.01.Although dark room and dark room glare contrast sensitivity fluctuated mildly after SBK,the measurements did not decline significantly.Compared with preoperative data,dark room contrast sensitivity at 3 months increased to 12 c/d (F=15.31,P＜0.05).Conclusion SBK performed by Winsight excimer laser is a predictable,effective and safe procedure for myopia and astigmatism. Key words: Keratomileusis, sub-Bowman's ;  Predictability ;  Efficacy ;  Safety ;  Contrast sensitivity