Corneal Biomechanics and Stromal Tissue Characteristics in Patients Undergoing SMILE

This prospective observational cohort study will investigate corneal biomechanical characteristics and their relationships with corneal stromal tissue features in adult patients undergoing clinically indicated small-incision lenticule extraction (SMILE). Participants will undergo standardized preoperative examinations, including Corvis ST assessment, refraction, axial length measurement, and corneal imaging. Corneal lenticules removed during routine SMILE surgery will be collected with informed consent and linked to clinical measurements from the corresponding eye using coded identifiers. The primary objective is to compare preoperative stiffness parameter at first applanation (SP-A1) between patients with high myopia and those with non-high myopia. Secondary objectives are to characterize postoperative biomechanical changes and clinical outcomes during 12 months of follow-up. Exploratory analyses will investigate relationships between stromal tissue characteristics and clinical biomechanical measurements. Surgical eligibility, surgical parameters, and postoperative care will be determined according to routine clinical practice independently of study participation. No additional corneal tissue will be removed for research.

Inclusion Criteria: * Age 18 years or older. Scheduled to undergo SMILE based on routine clinical assessment. At least one eligible eye with a manifest refractive spherical equivalent of -0.50 diopters or more myopic. Meets the institution's clinical criteria for SMILE, including refractive stability and contact lens discontinuation requirements. Able to provide written informed consent for clinical data collection, lenticule retention, and follow-up. Willing to attend scheduled postoperative assessments through 12 months. Exclusion Criteria: * Previous corneal refractive surgery or other surgery affecting corneal biomechanical assessment in the study eye. Known or suspected keratoconus, corneal ectasia, or clinically significant corneal scarring. Active ocular infection or inflammation. Diagnosed glaucoma or other ocular disease expected to materially affect interpretation of the study measurements. Systemic disease or medication use considered by the investigator to materially affect corneal wound healing or biomechanical assessment. Inability to provide informed consent or complete the required baseline examinations.