Abstract:Objective：This study aims to investigate the relationship between scotopic pupil and optical zone on short-term subjective and objective visual quality following small incision lenticule extraction (SMILE). Methods：In this prospective cohort study, 98 patients (196 eyes) who underwent SMILE surgery from September 2021 to June 2022 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). We assessed uncorrected visual acuity (UCVA), spherical equivalent (SE), subjective visual quality via a questionnaire, and total corneal high-order aberrations (corn-tHOA), as well as corneal spherical (corn-SA), coma (corn-COMA), and trefoil (corn-Tre) aberrations. The objective scatter index (OSI) was measured with central diameters of 4mm, 6mm and 8mm. Data were recorded preoperatively and at one month, three months postoperatively. The differences in refractive status, visual quality indexes between groups at various time points were analyzed and compared. Results：No significant differences in UCVA and SE were observed between the two groups at one month and three months postoperatively. Significant differences were noted in total corneal high-order aberrations at one month, as well as in total corneal high-order aberrations and spherical aberrations at three months. At three months after surgery, the most commonly reported symptoms in Group A were glare , starburst , hazy vision , and halo . In Group B, the most common symptoms were hazy vision, halo, starburst , and glare. Statistically signigicant differences were observed in the severity of glare and fluctuation between groups before and three months after surgery. However, there were no significant differences in the severity of halo, starburst, blurred vision, double vision, or focusing difficulty. Conclusion：When the diameter of dark pupils exceeds the optical region, SMILE may augment the postoperative corneal aberration, which is manifested in the increase of high-order corneal Aberrations within the postoperative cornea-centered 8mm range, the elevated incidence of postoperative glare, the severity of glare and visual fluctuation symptoms. However, the symptoms are mild and fall within the safe range.
