Correlation of retinal imaging with presence of inner limiting membrane pores in idiopathic epiretinal gliosis

Background To correlate retinal imaging biomarkers in idiopathic epiretinal membranes (iERM) with histopathological findings of internal limiting membrane (ILM) pores. Methods We retrospectively included 18 eyes of 18 patients diagnosed with iERM that underwent vitrectomy with membrane peeling between October 2023 and June 2024 at the Department of Ophthalmology, University Hospital Ulm, Germany. The surgically excised tissue was processed as flat mounts for immunocytochemistry. Clinical data and retinal architecture, as assessed by multimodal imaging including optical coherence tomography (OCT), enface OCT, fundus autofluorescence and multicolor imaging, were reviewed pre-and postoperatively. Results In our study, ILM pores were identified by immunocytochemistry in 15 of 18 specimens (83%). OCT showed ERM stage 2 in 11 eyes (61%), stage 3 in 6 eyes (33%) and stage 4 in 1 eye (6%), with central bouquet abnormalities in 6 of 18 eyes (33%) and ectopic inner foveal layers in 7 of 18 eyes (39%) of eyes. Postoperatively at 12 months, microcystic macular edema (MME) persisted in 3 of 18 eyes (17%) and resolved in one eye. Dissociated optic nerve fiber layer (DONFL) was observed in 15 of 18 eyes (83%). There was no significant correlation between ILM pores and iERM stage, the presence of ellipsoid zone defects, MME or DONFL (Fisher's exact test: each p > 0.05). Conclusion In iERM, ILM pores are highly frequently seen, but appear to be independent of ERM severity and retinal biomarkers. The presence of ILM pores was not found to be associated with anatomical alterations following ILM removal.