Temporal inverted internal limiting membrane flap technique versus conventional internal limiting membrane peeling technique for large macular holes: a retrospective comparative study

Abstract

Full-thickness macular holes (FTMHs) larger than 400 μm remain a surgical challenge with suboptimal closure rates when treated with conventional internal limiting membrane (ILM) peeling. The temporal inverted ILM flap technique has emerged as a promising alternative, yet direct comparisons-particularly regarding hole size specific outcomes and outer retinal microstructural recovery-remain scarce. This study aimed to compare the functional, anatomical, and morphological outcomes of these two surgical approaches. This retrospective study included 32 patients with large idiopathic FTMHs (> 400 μm) who underwent surgery between 2020 and 2024. Patients were divided into two groups: conventional ILM peeling (Group 1, n  = 16) and temporal inverted ILM flap technique (Group 2, n  = 16). All procedures were performed by a single experienced surgeon. Best-corrected visual acuity (BCVA), MH closure rate, closure configuration, diameter hole index (DHI), and outer retinal layer parameters including ellipsoid zone (EZ) and external limiting membrane (ELM) integrity were assessed using spectral-domain optical coherence tomography (SD-OCT) at baseline and 12 months postoperatively. Baseline characteristics did not differ significantly between the groups (all p  > 0.05). Both groups showed significant improvement in BCVA after surgery (both p  < 0.05). At 12 months, postoperative BCVA was 0.71 ± 0.46 logMAR in Group 1 and 0.38 ± 0.32 logMAR in Group 2, with significantly better BCVA in Group 2 ( p  = 0.039). Primary closure was achieved in 75.0% (12/16) of eyes in Group 1 and 100% (16/16) in Group 2, although the overall difference was not statistically significant ( p  = 0.101). In an exploratory post hoc subgroup analysis of eyes with a minimum hole diameter ≥ 550 μm, primary closure occurred in 33.3% (2/6) of Group 1 eyes and 100% (8/8) of Group 2 eyes ( p  = 0.015); both groups achieved 100% closure in holes measuring 400–549 μm. Postoperative EZ defect size was 1028.62 ± 606.93 μm in Group 1 and 539.12 ± 618.09 μm in Group 2, with a significantly smaller defect size in Group 2 ( p  = 0.040). In this retrospective, non-randomized cohort, the temporal inverted ILM flap technique was associated with better postoperative BCVA and a smaller postoperative EZ defect size than conventional ILM peeling. Although an exploratory post hoc subgroup analysis suggested a higher primary closure rate in Group 2 among eyes with a minimum hole diameter ≥ 550 μm, the overall closure-rate difference was not statistically significant, and the subgroup analysis was based on very small sample sizes. Further prospective studies with larger sample sizes are needed to confirm these findings. Not applicable (retrospective study).