Indistinct retinal outer layers in the walls of the idiopathic full-thickness macular hole - A potential predictive biomarker for surgical outcomes

Purpose: To evaluate the absence of external limiting membrane (ELM) and ellipsoid zone (indistinct retinal outer layers, I-ROL) in the walls of idiopathic full-thickness macular holes (FTMHs) circumferentially on optical coherence tomography (OCT) and its correlation with surgical outcome. Methods: In this retrospective observational study, OCT images of patients undergoing vitrectomy for FTMHs with at least 3-months of postoperative follow-up were analyzed for preoperative circumferential extent of I-ROL. Derived macular hole indices such as hole form factor (HFF), macular hole index (MHI), tractional hole index (THI), and hole diameter ratio (HDR) were also calculated. The circumferential extent of I-ROL was correlated with derived hole indices as well as anatomical closure, foveal architecture, and restoration of ELM following surgery. Results: All nine eyes (eight patients) with FTMH (mean size: 610.11 +/- 122.95 microns) in the study showed I-ROL in >= 1 quadrant. The mean HFF, MHI, THI, and HDR values were 0.72 +/- 0.09, 0.35 +/- 0.05, 0.71 +/- 0.24, and 0.53 +/- 0.14, respectively. All eyes achieved type-1 hole closure with improvement in best-corrected visual acuity to 0.58 +/- 0.32 LogMAR from 0.81 +/- 0.26 LogMAR. Regular foveal architecture was achieved in six eyes. Out of these, five eyes had I-ROL in >= 2 quadrants, and one eye had I-ROL in <2 quadrants (P = 0.0476). Restoration of ELM was seen in aforementioned six eyes (complete = 5, partial = 1). Out of the five eyes with complete ELM restoration, four had a circumferential extent of I-ROL in >= 2 quadrants (P = 0.0476). Complete restoration of ELM was associated with the complete restoration of the ellipsoid zone in three eyes. Conclusion: Preoperative circumferential extent of I-ROL in FTMH walls can be a potential predictive OCT marker for the type of closure, postoperative foveal architecture, and ELM restoration.