Corneal Surface Irregularity and Surgically Induced Astigmatism Changes in the Small Incision Versus Microincision After SMILE

Abstract Background: To evaluate the corneal surface irregularity and surgically induced astigmatism changes in the small incision versus microincision after small incision lenticule extraction (SMILE) surgery.Methods: A total of 70 eyes of 35 patients with myopia who underwent SMILE surgery were enrolled in this retrospective study. Patients were divided into two groups according to the incision size (small incision, 4.0 mm or microincision, <2.5 mm) and subjected to a standard ophthalmologic examination preoperatively. The changes in corneal topographic and surface irregularities were evaluated using a TMS-4N topographer during a 6-month follow-up period.Results: According to Friedman’s ANOVA test, there were statistically significant changed in SRI, SAI, and IOP between two groups during a 6-month follow-up (all p < 0.001). At last follow-up, SRI values less than 0.50 D were shown 27 eyes (75%) in the small incision group and 28 eyes (82%) in the microincision group; SAI values less than 0.50 D were shown 22 eyes (61%) in the small incision group and 18 eyes (53%) in the microincision group (all p<0.001).Conclusions: SMILE procedures, using both small incisions and microincisions, are safe and effective surgical options for patients with low to high myopia and provide stable postoperative biomechanical properties and superior postoperative visual outcomes.