Comparison of the visual results after small incision lenticule extraction and femtosecond laser-assisted LASIK for myopia.

摘要

During the past 3 years, several studies have suggested that small incision lenticule extraction (SMILE) is a promising alternative to LASIK for the correction of myopia. For this reason, we have read with great interest the article by Lin et al. about the comparison of the visual results after SMILE and femtosecond laser-assisted LASIK (FS-LASIK) for the treatment of myopia. However, we have concerns about two facts of this study. First, when reading the preoperative demographics, we have observed that the preoperative cylinder was higher in the FS-LASIK group than in the SMILE group, with a surprising P value of 1.101 for the comparison of this parameter between both groups. We remark that the maximum possible P value is 1.0, which is an exceptional statistical situation that is only found when the parameter compared in two groups is exactly equal in both. Given the fact that the amount of preoperative astigmatism may be relevant in the refractive outcomes of the procedure, we invite the authors to revise this P value.