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

ABSTRACT

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.