Small-Incision Lenticule Extraction with Prophylactic Cross-Linking: A Systematic Review and Meta-Analysis.

TOPIC: Keratorefractive lenticule extraction (KLEx) treats myopia and myopic astigmatism while preserving corneal biomechanics better than flap-based procedures. KLEx with prophylactic accelerated corneal cross-linking (KLEx-CXL) has been proposed for thinner corneas, higher myopia, or borderline tomography, but its incremental value remains uncertain. CLINICAL RELEVANCE: KLEx-CXL may reduce biomechanical instability, but adds operative time, cost, and protocol variability. Comparative evidence is needed to determine whether it improves outcomes over KLEx alone. METHODS: MEDLINE, Embase, Scopus, Web of Science, CENTRAL, and CINAHL were searched to July 2, 2026. Comparative adult studies with at least 6 months' follow-up reporting refractive or visual outcomes were included. Two reviewers extracted data, assessed risk of bias, and rated certainty using GRADE. Random-effects meta-analyses pooled mean differences. RESULTS: Nine studies included 730 eyes: 386 KLEx and 344 KLEx-CXL. Residual MRSE was similar overall (MD 0.03 D; 95% CI, -0.01 to 0.06; P=0.17), with no consistent timepoint-specific difference. A small residual difference was confined to moderate-myopia cohorts (0.09 D; 95% CI, 0.04 to 0.15) and absent in high myopia. KLEx showed a 1-month advantage in uncorrected distance vision (MD -0.04 logMAR), safety index (MD 0.07), and efficacy index (MD 0.08), resolving by 12 months. Corrected vision was similar throughout. Biomechanical measures favored KLEx-CXL. Early haze was transient; no ectasia occurred. Certainty was low. CONCLUSION: KLEx and KLEx-CXL achieved similar residual refraction and corrected visual acuity. KLEx-CXL produced measurable biomechanical reinforcement but transiently delayed early uncorrected visual recovery. Current evidence supports reserving prophylactic cross-linking for higher-risk eyes.