Effect of Centration Compensation on Visual Quality in VisuMax 800 SMILE for Small Kappa Angles: A Randomized Trial
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.
• Voluntarily agree to undergo SMILE surgery on the VISUMAX 800 platform, understand the randomization scheme, and provide signed informed consent.