Large idiopathic macular hole surgery: remodeling of outer retinal layers after traditional internal limiting membrane peeling or inverted flap technique.

To investigate the influence of the inverted flap technique compared with the traditional internal limiting membrane (ILM) peeling in the postoperative remodelling of outer retinal layers of idiopathic MHs larger than 450 μm.We analyzed medical records and imaging studies of all patients with idiopathic macular hole (MH) >450 μm who underwent vitrectomy at Sacco University Hospital and at the Sacro Cuore Don Calabria Hospital between January 2008 and December 2017. Out of 41 eyes evaluated, 17 were treated with traditional ILM peeling and 24 with inverted ILM flap technique. All patients underwent follow-up examinations every three months and all of them completed a final visit twelve months after surgery. Best-corrected visual acuity (BCVA) and optical coherence tomography (OCT) parameters were evaluated at each visit. Main outcome measures were postoperative recovery rate of external limiting membrane (ELM) and ellipsoid zone (EZ) and postoperative BCVA. Correlations between OCT measures and visual outcome were analyzed.The ELM recovery rate in the ILM peeling group (15/17 eyes, 88%) was higher than in the ILM flap group (14/24 eyes, 58%) (P=0.079). The EZ recovery rate was similar between the two groups, 7/17 eyes (41%) in the ILM peeling and 8/24 eyes (33%) in the ILM flap group (P= 0.744). Eyes without a persistent hyper-reflective "plug" between the edges of MH showed a significantly higher EZ recovery rate (11/18, 61%) as compared with eyes showing a persistent "plug" (4/23, 17%) (P=0.008). The mean BCVA improved significantly in both groups: from 0.93 logMAR to 0.26 logMAR in the ILM peeling and from 0.98 logMAR to 0.37 logMAR in the ILM flap group. The final BCVA tended to be better in the ILM peeling group (P=0.085).Given the limited informations about the influence of ILM flap as compared with traditional ILM peeling in the postoperative remodelling of large idiopathic MHs, our data provide some new insights about the healing process of MH>450 μm. This should be considered in the decision process whether to perform an ILM flap in this patient group.