Comparison of Different Internal Limiting Membrane Peeling Sizes for Idiopathic Macular Holes: A Systematic Review and Meta-Analysis

Background: Although internal limiting membrane (ILM) peeling facilitates macular hole (MH) closure and reduces late hole reopening, it brings some detrimental consequences to the retinal microstructure and functional outcomes. So far, previous studies have not reached a consensus on the optimal ILM peeling size. Objectives: The objective of this study was to evaluate the outcomes of different ILM peeling sizes for idiopathic MHs. Methods: PubMed, Embase, Cochrane Library, Web of Science, CNKI, and WANFANG were searched until April 10, 2022. Studies in English or Chinese that compare the effects of two ILM peeling sizes (>2 disk diameters [DDs] vs. <= 2DD) for idiopathic MHs were included. The overall closure rate, postoperative best-corrected visual acuity (BCVA), type 1 closure, and adverse events were extracted. BCVA was converted to logarithm of the minimum angle of resolution (LogMAR). Results: Seven eligible studies (560 eyes) including 3 randomized clinical trials, 3 prospective trials, and one retrospective cohort were included. Pooled results showed a significantly better postoperative BCVA (mean difference = -0.16; 95% confidence interval [CI]: -0.27 to -0.04; LogMAR) and higher type 1 closure rate (risk ratio [RR] = 1.24; 95% CI: 1.08-1.43) in eyes with ILM peeling >2DD than those with peeling <= 2DD. No significant difference was found in overall closure rate and adverse events between the two groups. Subgroup analysis indicated that in MHs >400 mu m, peeling >2DD helped obtain a better postoperative BCVA (mean difference = -0.17; 95% CI: -0.29 to -0.04; LogMAR) and higher frequency of type 1 closure (RR = 1.25; 95% CI: 1.03-1.51). Conclusions: Peeling >2DD shares similar safety level with peeling <= 2DD and has a superiority of facilitating visual recovery. Larger ILM peeling may be more beneficial for large MHs.