Inverted Internal Limiting Membrane Flap versus Internal Limiting Membrane Peeling for <400 μm Macular Hole: A Meta-Analysis and Systematic Review

INTRODUCTION: The inverted internal limiting membrane (ILM) flap technique was initially developed for the closure of large macular holes (MHs). However, its efficacy in treating small holes has been a matter of debate. This study aimed to compare the anatomical and visual outcomes of vitrectomy (PPV) combined with the inverted ILM flap and ILM peeling in cases of small and medium-sized MHs. METHODS: A meta-analysis was conducted by searching the relevant literature in databases, including PubMed, Web of Science, Embase, and Cochrane Library. The search included articles published from the inception of the databases up until January 2023. The inclusion criteria limited the studies to only experimental-based research. The heterogeneity, publication bias, and sensitivity analysis were performed to ensure the statistical power and reliability of the analysis. RESULTS: Five studies, including two non-randomized concurrent control trials and three non-randomized concurrent control trials, comprising a total of 269 eyes, were analysed. The results showed no significant difference in the MH closure rate between the two groups (odds ratio (OR) = 0.29, 95% confidence interval: 0.04–1.96, p = 0.33). Furthermore, there were no significant differences observed in visual acuity, external limiting membrane (ELM), and ellipsoid zone (EZ) integrity at 3 months (ELM OR = 0.88, EZ OR = 0.85) or 12 months (ELM OR = 0.96, EZ OR = 1.39) post-operation between the two groups. CONCLUSION: The surgical repair of MHs smaller than 400 μm with ILM flap seems to be similar in visual acuity improvement and anatomical recovery compared to the traditional technique.