Insights Into Epiretinal Membranes: Presence of Ectopic Inner Foveal Layers and a New Optical Coherence Tomography Staging Scheme

PURPOSE: To describe the presence of continuous ectopic inner foveal layers associated with epiretinal membranes (ERMs) and to present a new optical coherence tomography (OCT) staging system of ERMs. DESIGN: Retrospective multicenter observational case series. METHODS: Clinical charts and spectral-domain OCT images of 194 eyes of 172 consecutive patients diagnosed with ERMs were reviewed and analyzed. RESULTS: The presence of continuous ectopic inner foveal layers was identified in 63 out of 194 eyes (32.5%) and this morphology was significantly associated with lower visual acuity. ERMs were divided into 4 stages. Stage 1 (43 out of 194 eyes, 22.1%) ERMs were mild and thin and a foveal depression was present. Stage 2 (88 out of 194 eyes, 45.4%) ERMs were associated with widening of the outer nuclear layer and loss of the foveal depression. Stage 3 (51 out of 194 eyes, 26.3%) ERMs were associated with continuous ectopic inner foveal layers crossing the entire foveal area. In stages 1, 2, and 3 all retinal layers were clearly defined on OCT. Stage 4 ERMs (12 out of 194 eyes, 6.2%) were thick and associated with continuous ectopic inner foveal layers. In addition, retinal layers were disrupted. Visual acuity progressively declined from stage 1 through stage 4 (P < .001). CONCLUSIONS: The presence of continuous ectopic inner foveal layers in ERMs is a newly described OCT finding associated with significant vision loss and is an essential element of a novel OCT-based grading scheme of ERMs that may influence visual prognosis.