Short-Term Impact of Different Corneal Incision Positions on Postoperative Astigmatism and Visual Quality After SMILE Surgery

Abstract Introduction This study aimed to evaluate the short-term impact of different incision positions on astigmatism and visual quality after small incision lenticule extraction (SMILE) surgery. Methods This prospective study enrolled patients who decided to have SMILE to correct myopia. Patients were randomly allocated into three groups of different incision positions (group A, B, and C with incision position at 90°, 120°, and 150° respectively). Preoperative and postoperative visual acuity, spherical equivalent, and high-order aberrations (HOAs) were measured and compared among groups. Astigmatism was analyzed with the ASSORT Group Analysis Calculator based on the Alpins method. Results A total of 148 eyes were included for analysis (48 eyes in group A, 50 eyes in group B, and 50 eyes in group C). At 1 month postoperatively, the mean uncorrected distance visual acuity (UDVA) logMAR in group A, B, and C was − 0.03, − 0.03, and − 0.04, respectively. The mean corrected distance visual acuity (CDVA) logMAR in group A, B, and C was − 0.03, − 0.04, and − 0.04, respectively (P > 0.05). The mean postoperative spherical equivalent (SE) values were − 0.01 ± 0.38, − 0.07 ± 0.39, and − 0.16 ± 0.49 (D) in group A, B, and C, respectively (P > 0.05). There was no statistically significant difference in preoperative and postoperative magnitude of astigmatism among different groups (P > 0.05). Significant differences were found in the distribution of astigmatism axis among the three groups at 1 day (P = 0.02) and 1 week (P = 0.02) postoperatively. However, such differences were no longer significant at 1 month after surgery (P > 0.05). No significant differences were found in HOAs among different groups 1 month after surgery (P > 0.05). Conclusion Different incision positions have no effect on postoperative astigmatism and visual quality 1 month after SMILE surgery, though differences were found in the distribution of the astigmatism axis within 1 week after the surgery.