Long-Term Structural and Functional Restoration of the Retina After Inverted Internal Limiting Membrane Flap Surgery for Idiopathic Full-Thickness Macular Holes

Abstract

Objectives: To characterise longitudinal structural and functional retinal restoration after inverted internal limiting membrane (ILM) flap surgery for idiopathic full-thickness macular holes (FTMHs), with a particular emphasis on postoperative glial proliferation, outer retinal restoration, and structure–function relationships. Methods: This retrospective consecutive case series included 46 eyes of 44 patients with idiopathic FTMH treated using the inverted ILM flap technique. Spectral-domain optical coherence tomography (SD-OCT), best-corrected visual acuity (BCVA), microperimetry, fixation stability, and multifocal electroretinography (mfERG) were performed 1, 6, and 12 months postoperatively. Results: Anatomical closure was achieved in all eyes. Complete restoration of both the ELM and EZ increased from 8.7% at 1 month to 45.7% at 6 months and 54.3% at 12 months, whereas severe glial proliferation decreased from 30.4% to 15.2% at 12 months. BCVA, retinal sensitivity, fixation stability, and central mfERG responses improved predominantly between 1 and 6 months postoperatively. In multivariable analysis, lower closure-pattern grade (B = −0.073, 95% CI: −0.141 to −0.005; p = 0.035) and lower glial proliferation grade (B = −0.091, 95% CI: −0.155 to −0.027; p = 0.006) were independently associated with better BCVA at final visit. Conclusions: Retinal healing after inverted ILM flap surgery is a coordinated, time-dependent process involving regression of postoperative gliosis, restoration of the outer retinal microstructure, and multimodal functional recovery. Longitudinal integration of OCT with microperimetry, fixation analysis, and mfERG provides a comprehensive framework for understanding postoperative retinal remodelling beyond anatomical hole closure.