Comparison of surgical outcomes following femtosecond laser-assisted LASIK (Femto-LASIK) versus small incision lenticule extraction (SMIL) for myopia and astigmatism

Abstract Purpose To compare the visual, refractive, and topographic outcomes of patients who underwent Femto-LASIK and SMILE. Methods This historical cohort study selected 83 eyes of 83 patients with myopic and myopic astigmatism. Patients were divided into two groups based on the surgical procedure: femto-LASIK-treated (46 patients) and SMILE-treated patients (37 eyes). In all patients, corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), spherical component, spherical equivalent (SE), cylindrical component, and some tomography readings were measured preoperatively and compared with the outcomes 45 days after surgery. In addition, the symptoms reported by patients were investigated in follow-ups on the 10th, 30th, and 45th days following the operation. Results Significantly better spherical refractive outcomes were associated with SMILE than Femto-LASIK at 45 days postoperatively (sphere component: -0.22 ± 0.61 D for Femto-LASIK and − 0.04 ± 0.17 D for SMILE, and P = 0.080; SE: -0.37 ± 0.72 D for Femto-LASIK and − 0.09 ± 0.21 D for SMILE, and P = 0.021). In addition, the SMILE procedure induced more flattening effect on steep-K readings than Femto-LASIK 45 days after the surgery (41.96 ± 2.23 D for SMILE and 40.65 ± 2.04 D for Femto-LASIK, and P = 0.007). No significant differences were found between the two study groups' postoperative measurements of flat-K and K-max. In addition, the higher proportions of patients who were treated with SMILE complained of severe dryness sensation at ten days postoperatively, no patient complained of this symptom at 45 days following both procedures. Conclusions By the end of the 45-day follow-up after the operation, SMILE would be a slightly better surgical procedure providing less postoperative myopic refraction and fewer symptoms.