To compare laser in situ keratomileusis (LASIK) and Simultaneous LASIK and accelerated Crosslinking (LASIK Xtra) for myopia correction.

Systematic review and meta-analysis.

A search of PubMed, EMBASE, Web of Science, the Cochrane Library, and China National Knowledge Internet was conducted up to October 1, 2024 to identify studies comparing LASIK and LASIK Xtra for myopia correction. The outcome of visual acuity and refraction, safety, efficiency, predictability, stability, postoperative corneal thickness and endothelial cell count were measure.

A total of 1,647 eyes (836 LASIK, 811 LASIK Xtra) from 15 studies were included. LASIK demonstrated superior postoperative uncorrected distance visual acuity (UDVA) compared to LASIK Xtra, with a mean difference (MD) of –0.03 (8 studies, n = 750 eyes; 95% CI: –0.04 to –0.01, P = .007) at 1 month and (7 studies, n = 672 eyes; MD= –0.01 95% CI: –0.02 to 0.00, P = .02) for long-term results (≥6 months). No significant differences were found in corrected distance visual acuity (CDVA; 6 studies, n = 530 eyes; MD = 0.00, 95% CI: –0.01, 0.00, P = .32), spherical equivalent (14 studies, n = 1639 eyes; MD = 0.03, 95% CI: −0.03, 0.08; P = .40), safety (8 studies, n = 779 eyes; odds ratios [OR]= 0.70; 95% CI: 0.39, 1.26; P = .23), efficiency (11 studies, n = 921 eyes; OR = 0.75, 95% CI: 0.54, 1.05, P = .10), predictability (11 studies, n = 971 eyes; OR= 1.03, 95% CI: 0.72, 1.47, P = .86), stability (3 studies, n = 90 eyes; OR = 0.70, 95% CI: 0.21, 2.28, P = .55). Subgroup analysis indicated a higher risk of postoperative CDVA loss in the Ectasia Risk Group undergoing LASIK-Xtra (OR= 0.20, 95% CI: 0.04 to 0.97, P = .05). The 30 mW/cm² for 90 seconds (2.7 J/cm²) irradiation protocol in LASIK Xtra may resulted in worse UDVA compared to LASIK (MD= –0.01, 95% CI: –0.03 to –0.001, P = .05). The certainty of evidence for the outcomes ranged from "low to very low".

Current evidence suggests that LASIK offers a statistically significant advantage in UDVA compared to LASIK Xtra, especially when LASIK Xtra irradiation protocol of 30 mW/cm² for 90 seconds (2.7 J/cm²) is applied. However, given the low to very low certainty of evidence, these findings require cautious interpretation and further confirmation through long-term studies.