Prospective evaluation of axial length and refractive stability after small-incision lenticule extraction in young adults with progressive myopia.

Abstract

This study aimed to evaluate the effect of small-incision lenticule extraction (SMILE/KLEx) on axial length (AXL) progression and refractive stability in young adults with moderate to high myopia and documented preoperative progression. This prospective study included 100 eyes of 50 patients aged 18-21 years who underwent SMILE/KLEx. AXL, spherical equivalent (SE), corneal curvature, and central corneal thickness (CCT) were measured 1 year pre-baseline (T - 1), at baseline (T0), and postoperatively at 6 months (T1), 1 year (T2), and 3 years (T3). Agreement between estimated and observed AXL elongation was assessed using Bland-Altman analysis, and generalized estimating equation (GEE) models were used to account for inter-eye correlations and evaluate changes from baseline. Median AXL showed limited progression throughout follow-up (26.05 mm at T0, 26.14 mm at T2, 26.26 mm at T3), SE improved from - 6.00 D to - 0.25 D, and corneal parameters showed early postoperative changes followed by long-term stability. Visual outcomes were satisfactory, with no significant intraoperative or postoperative complications. In conclusion, SMILE/KLEx provided effective refractive correction in this cohort of young adults with documented preoperative myopic progression. Over 3 years, axial length showed no statistically significant progression at the group level, although individual-level elongation was heterogeneous and remained within the expected physiological range for young adults.