Inverted internal limiting membrane flap technique versus complete internal limiting membrane peeling in large macular hole surgery: a comparative study

Abstract Background To compare the anatomical and functional outcomes of the inverted internal limiting membrane (ILM) flap technique and the complete ILM removal in the treatment of large stage 4 macular hole (MH) > 400 μm and to evaluate reconstructive anatomical changes in foveal microstructure using spectral-domain optical coherence tomography. Methods This is a retrospective, consecutive, nonrandomized comparative study of patients affected by idiopathic, myopic or traumatic stage 4 MH (minimum diameter > 400 μm) treated with 25-gauge pars-plana vitrectomy with either complete ILM peeling (n = 23, Group 1) or inverted ILM flap technique (n = 23, Group 2), between August 2016 and August 2018. Main outcomes measured were the MH closure rate assessed by spectral-domain optical coherence tomography and the best-corrected visual acuity (BCVA) at six months. Foveal microstructure reconstructive changes were evaluated using SD-OCT to determine predictive factors of postoperative BCVA. Results Closure of MH was achieved in 16/23 cases of Group 1 (70%) and in 22/23 cases of the Group 2 (96%). Surgical failure was reported in 6 cases of Group 1 and 1 case of Group 2. The MH closure rate was significantly higher with the inverted ILM flap technique (P-value = 0.02). Average BCVA (LogMAR) changed from 1.04 ± 0.32 to 0.70 ± 0.31 in Group 1 and from 0.98 ± 0.22 to 0.45 ± 0.25 in Group 2 (P-value = 0.005) at 6 months. Improvement in BCVA (> 0.3 LogMAR units) was statistically higher in the Group 2 (P-value = 0.03). Restoration of foveal microstructure was significantly higher in the Group 2 at 6 months (52% vs 9%, P-value 400 μm, improving both anatomical and functional outcomes. Early recovery of the external limiting membrane at 3 months is a positive predictive value of postoperative BCVA 6 months after inverted ILM flap technique.