Optical Coherence Tomography Biomarkers Differentiate Epiretinal Membranes Secondary to Retinal Detachment from Idiopathic Epiretinal Membranes

Purpose: To identify distinguishing optical coherence tomography (OCT) characteristics of epiretinal membranes (ERMs) secondary to retinal detachment compared with idiopathic ERMs. Methods: This retrospective study analyzed 2 cohorts treated at a tertiary referral center: ERM following rhegmatogenous retinal detachment (RRD) and idiopathic ERM. Only patients who underwent pars plana vitrectomy with membrane peeling were included. Preoperative OCT images were reviewed and graded. Results: Postoperative best-corrected visual acuity improved in both groups. In the post-RRD ERM cohort, visual acuity improved from 0.71 to 0.64 (Snellen equivalents, approximately 20/100 to 20/80), while in the idiopathic ERM cohort, it improved from 0.44 to 0.32 (approximately 20/60 to 20/40). Post-RRD ERMs were of higher stage, with 80% classified as stage 3 or 4 compared with 61% in the idiopathic group ( P = .048). Disorganization of the retinal inner layers was more prevalent in post-RRD ERM, with 42% demonstrating grade 3 or 4 compared with 15% in idiopathic ERM ( P = .02). Foveal herniation was observed in 40% of post-RRD ERMs compared with 14% of idiopathic ERMs ( P = .009). A gap between the ERM and the retinal surface was more frequently identified in idiopathic ERM (62%) than in post-RRD ERM (17%) ( P < .001). Conclusions: ERMs following RRD exhibit more severe OCT characteristics, including higher staging, increased prevalence of foveal herniation, and lower incidence of a gap between the ERM and the retinal surface. The presence of these OCT characteristics should raise suspicion for prior retinal tear or retinal detachment and may indicate a worse visual prognosis and increased surgical complexity.