Relationship between corneal cutting ratio and early postoperative Q values and higher-order aberrations after small incision lenticule extraction in myopic patients

This study investigates the association between the corneal cutting ratio and early postoperative corneal Q values and higher-order aberrations (HOAs) after small incision lenticule extraction (SMILE) in myopic patients. A total of 149 patients (288 eyes) with refractive errors who underwent SMILE in our hospital from January 2017 to December 2021 were included. Both eyes were included when they met the eligibility criteria; therefore, the eye was used as the unit of analysis. According to the cutting ratio (corneal cutting depth/preoperative corneal thickness), eyes were divided into the ≤0.16 group (n = 96) and >0.16 group (n = 192). Preoperative and 1-month postoperative uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), corneal HOAs, and corneal Q values were compared. Pearson correlation analysis was used to assess the associations between cutting ratio and corneal optical parameters. There were no significant differences in baseline refractive parameters or preoperative BCVA, total HOAs, and corneal Q values between the 2 groups (all P > .05), and no significant differences in postoperative UCVA or BCVA (P > .05). The >0.16 group had significantly higher total HOAs and corneal Q values at 1 month than the ≤0.16 group (P < .05). The cutting ratio was positively correlated with total HOAs and corneal Q values (R = 0.462 and 0.432, respectively; both P < .001). At 1 month after SMILE, a higher cutting ratio was associated with higher corneal Q values and HOAs. Because bilateral eyes from some patients were included and follow-up was limited to 1 month, these findings should be interpreted as early postoperative associations rather than evidence of a long-term visual-quality outcome.