Comparison of visual quality after SMILE correction of low-to-moderate myopia in different optical zones.

"Declarations Conflict of interestThe authors have no conflicts of interest to declare. Ethical approvalThis study was approved by the ethics committee of The Second Affiliated Hospital of Harbin Medical University Review Board (KY2021–011). Informed consentAll patients signed informed consent forms before the surgery. Conflict of interest The authors have no conflicts of interest to declare."

"Funding This work was supported by Heilongjiang Province Postdoctoral Research Startup Fund."

"This retrospective case–control study involved a total of 100 patients (200 eyes) who underwent SMILE surgery at the Second Affiliated Hospital of Harbin Medical University between October 2018 and July 2019. The inclusion criteria were as follows: age, 18 years or older; no history of eye disease or trauma; transparent cornea without haze or macula; soft contact lens wearers who had not worn contacts for more than 2 weeks or rigid contact lens wearers who had not worn contacts for more than 4 weeks; and annual increase in refractive error < 0.50 D within 2 years. The exclusion criteria were as follows: corneal thickness did not meet the requirements for surgery, keratoconus or suspected keratoconus, and other serious ocular or systemic diseases. The patients were divided into 2 groups based on the preoperatively planned optical-zone diameter: a 6.5 mm group (50 patients, 100 eyes) and a 6.8 mm group (50 patients, 100 eyes). The selection of the optical-zone diameter depended on the patients’ dark-room pupillary diameter and corneal thickness. All operations were performed independently by YL. This study was approved by the ethics committee of The Second Affiliated Hospital of Harbin Medical University Review Board (KY2021–011), and this trial was registered in the Chinese Clinical Trial Registry (ChiCTR2100044212). All patients signed informed consent forms before the surgery."