The goal of this clinical trial is to evaluate the effect of intraoperative kappa-angle compensation on postoperative visual quality in patients undergoing small incision lenticule extraction (SMILE) using the VisuMax 800 platform. The study will enroll patients with myopia and a kappa-angle offset \< 0.2 mm.
The main questions it aims to answer are:
Does intraoperative kappa-angle compensation reduce postoperative higher-order aberrations after SMILE? Does kappa-angle compensation improve postoperative visual quality and refractive outcomes compared with no compensation?
Researchers will compare SMILE with intraoperative kappa-angle compensation to SMILE without compensation to determine whether compensation leads to better optical quality and visual performance.
Participants will:
Undergo SMILE surgery with or without intraoperative kappa-angle compensation Complete scheduled postoperative examinations at 1 week, 1 month, 3 months, and 6 months after surgery Receive measurements of visual acuity, refraction, higher-order aberrations, contrast sensitivity, and safety outcomes
Patients aged 18 to 40 years with myopia or myopic astigmatism and stable refraction for >=1 year, whose refractive errors fall within the treatable range of and meet the indications for SMILE surgery.
Normal corneal morphology and corneal thickness meeting surgical requirements.
Preoperative corrected distance visual acuity (CDVA) >= 1.0.
Preoperative synthetic Kappa angle offset measured >= 0.10 mm and < 0.20 mm.
History of prior ocular surgery, significant ocular trauma, or presence of corneal or ocular diseases that may affect the safety of refractive surgery.
Severe systemic diseases that may affect ocular healing or surgical safety.
Females who are pregnant or lactating.
Inability to cooperate as required to complete the procedure or follow-up visits.