AIM: To investigate the effect of the relationship between scotopic pupil and optical zone diameters on short-term subjective and objective visual quality after small incision lenticule extraction(SMILE).METHODS:In this prospective cohort study, 98 patients(196 eyes)who underwent SMILE from September 2021 to June 2023 were included. Participants were divided into two groups based on the ratio of scotopic pupil diameter to optical zone diameter: group A(ratio >1, 70 eyes)and group B(ratio ≤1, 126 eyes). The preoperative and postoperative uncorrected visual acuity(UCVA), spherical equivalent(SE), total corneal high-order aberrations at 4, 6, and 8 mm of pupil diameters, objective scatter index(OSI), pre- and post-operative QoV subjective visual quality questionnaire were observed and recorded. The refractive status of different groups of patients at different time points before and after surgery, and differences in subjective and objective visual quality indices were analyzed. Furthermore, the changes in subjective and objective visual quality(postoperative-preoperative)at different postoperative time points were analyzed between the two groups.RESULTS:No significant differences in visual acuity or refractive state were observed between the two groups at 3 mo postoperatively. In both the group A and the group B, there was a difference in the changes of corneal total higher-order aberration centered on 8 mm cornea at 1 mo postoperatively(P<0.05), and there was a difference in the changes of total higher-order aberration and corneal spherical aberration centered on 8 mm cornea at 3 mo postoperatively(all P<0.05). At 3 mo after surgery, the most commonly reported symptoms in the group A were glare, starburst, hazy vision, and halo. In the group B, the most common symptoms were hazy vision, halo, starburst, and glare. Statistically significant differences were observed in the severity of glare and visual fluctuation between groups before surgery and at 3 mo postoperatively(all P<0.05). However, no significant differences were found in the severity of halo, starburst, blurred vision, double vision, or focusing difficulty at 3 mo postoperatively(all P>0.05).CONCLUSION:When the scotopic pupil diameter exceeds the optical zone, SMILE may increase postoperative corneal aberrations, as evidenced by an increase in high-order corneal aberrations within an 8-mm central corneal range, a higher incidence of postoperative glare, and more severe glare and visual fluctuation symptoms. Nevertheless, these symptoms are mild and remain within a safe range.