Visual and refractive outcomes of small incision lenticule extraction planned with a VISULYZE-generated nomogram for myopia and astigmatism: a retrospective comparative study.

Small incision lenticule extraction (SMILE) has become a widely adopted refractive surgical procedure for correcting myopia and myopic astigmatism due to its flapless design, minimal invasiveness, and favorable biomechanical properties [–]. Compared to excimer laser–based procedures, SMILE has been associated with reduced postoperative dry eye symptoms and a lower incidence of flap-related complications [, ]. Numerous clinical studies have demonstrated that SMILE provides safe, effective, and stable refractive outcomes for myopia and low to moderate astigmatism [–]. However, variability in refractive predictability, particularly in astigmatism correction, remains a concern. Studies have reported undercorrection, overcorrection, and astigmatic axis deviation following SMILE, even in eyes with low cylindrical error [, ]. These discrepancies may be due to various factors, including variability in subjective refraction, limitations of conventional nomogram-based planning, cyclotorsional misalignment, and the lack of intraoperative eye tracking or dynamic axis compensation [, ]. Nomogram planning plays a crucial role in improving refractive predictability by compensating for systematic treatment biases. Traditional nomograms rely on accumulated surgical experience and postoperative outcomes, adjusting laser parameters to minimize over- or undercorrection trends [, ]. However, they may not fully account for surgeon-specific factors or changes in surgical technique over time.