Comparison of SMILE surgery and femtosecond laser LASIK for myopia

Abstract

Objective To compare and evaluate the postoperative outcomes of small incision lenticule extraction (SMILE) and laser in situ keratomileusis with femtosecond laser (FS-LASIK)for myopia.Methods Thirty-six patients (72 eyes) with myopia were selected for small incision lenticule extraction (SMILE group) and another 35 patients (70 eyes) were selected for laser in situ keratomileusis with femtosecond laser (FS-LASIK group).Uncorrected visual acuity (UCVA),best corrected visual acuity (BCVA),spherical equivalent (SE) and wavefront aberration were measured preoperatively and at 1 day and 7 days and 1 month,3 months and 6 months postoperatively.Total higher order aberrations (HOAs),horizontal and vertical comas,and spherical aberrations were recorded with the Zywave system.Data were analyzed using a chi square test and independent samples t test.Results The UCVA in the FS-LASIK group was better than the UCVA for the SMILE group at postoperative 1 day.The 2 groups had similar UCVAs at 7 days and 1 month postoperatively.The UCVA in the SMILE group was better than UCVA for the FS-LASIK group at 3 months postoperatively.At different time points after the operations,there were no significant differences in UCVA≥preoperative BCVA between the 2 groups.Differencs in SE between the 2 groups were not statistically significant at 7 days and 6 months postoperatively.Total HOA root mean square (RMS) showed an increase in both groups postoperatively,and a decline at 3 months and 6 months postoperatively.The HOA of the SMILE group was lower than that of the FS-LASIK group,but the difference between the 2 groups was not statistically significant.The spherical aberrations of the 2 groups increased significantly at 1 day,7 days,1 month and 6 months postoperatively but declined by 6 months postoperatively.Vertical coma increased in the 2 groups after the operations but declined after 3 months postoperatively,falling close to preoperative levels at 6 months postoperatively.Horizontal coma in the two groups increased significantly after the operations.There were no significant differences between the two groups for HOA,spherical aberration,vertical coma and horizontal coma at any time points after the operation.Conclusion SMILE and FS-LASIK are safe and effective in the treatment of myopia.Both SMILE and FS-LASIK can increase total HOA,spherical aberration,vertical coma and horizontal coma. Key words: Femtosecond laser; Small incision lenticule extraction; Keratomileusis,laser in situ ; Myopia ; Wavefront aberration