Corneal stability comparison between prophylactic cross-linking with laser refractive surgery technique versus laser refractive surgery technique alone for myopia: a meta-analysis

Purpose To summarize whether corneal cross-linking (CXL) with laser refractive surgery improves corneal stability more than laser surgery alone for myopia. Methods Five electronic databases were systematically searched from inception to Aug, 2023. Studies comparing the effects of prophylactic corneal CXL with laser refractive surgery technique versus laser refractive surgery technique alone in myopic eyes were included. The included articles regarding prophylactic CXL combination with laser refractive surgery technique, riboflavin was all delivered into the stroma with similar accelerated protocols (irradiance of 30mW/cm 2 for 60-90 seconds). Primary outcome measures included post-operative changes of keratometry, refraction, corneal thickness, endothelial cell density, and both corrected and uncorrected distance visual acuity (CDVA/UDVA) as the surrogate parameters to corneal stability, measured from post-operative 1-12 and 1-24 months. Meta-analysis was performed using random-effect models, and potential sources of heterogeneity were explored by subgroup analyses of surgery type and myopic level. Results Twelve eligible studies with 1,252 eyes met our inclusion criteria. Compared to those receiving laser refractive surgery technique alone, patients who received prophylactic CXL with laser refractive surgery technique had significantly less UDVA and CDVA decrease within post-operative 12 months (UDVA:WMD -0.04, 95% CI -0.06-(-0.01), p =0.01/CDVA: WMD -0.01, 95% CI -0.03-(-0.00), p =0.02). Furthermore, patients with spherical equivalent ≤ ≤ -5.0 Diopter (UDVA:WMD -0.04, 95% CI -0.07-(-0.02), p <0.001/ CDVA: WMD -0.02, 95% CI -0.03-(-0.01), p <0.001) or receiving LASIK procedures (UDVA:WMD -0.03, 95% CI -0.06-(-0.01), p =0.01) were associated with more profound visual stability after prophylactic CXL. Conclusion For visual outcome, prophylactic CXL with laser refractive surgery, compared to laser refractive surgery alone, provided more stability within post-operative one-year among myopic patients with comparable efficacy and predictability. Particularly, those with higher myopia or receiving LASIK procedure as refractive surgery benefited more from prophylactic CXL.