Epiretinal Membrane: OCT Staging and When to Operate

Last updated: November 2026

An epiretinal membrane (ERM) is a sheet of fibrocellular tissue on the inner retinal surface that wrinkles the macula. Most are idiopathic and mild; the skill is deciding which patients will benefit from surgery.

Clinical features

• Blurred vision and metamorphopsia (distortion), sometimes micropsia or monocular diplopia.
• A glistening "cellophane" reflex, then a grey membrane with retinal striae and vessel tortuosity.
• Usually idiopathic after posterior vitreous detachment; secondary causes include retinal tears and detachment surgery, retinal vascular disease, uveitis and trauma.

OCT signs and staging

A hyperreflective line on the inner retina with loss of the foveal dip and increased thickness. Govetto staging (2017):

When to operate

• Symptomatic loss of vision (often around 6/12 or worse) or troublesome distortion affecting daily life.
• Surgery: pars plana vitrectomy with membrane peel, often with internal limiting membrane (ILM) peel using a dye (brilliant blue) to reduce recurrence.
• Most patients gain some vision and have less distortion, but distortion rarely disappears completely. Cataract progresses in most phakic eyes within 2 years.
• Poorer prognosis: stage 4 EIFL, disrupted ellipsoid zone, long duration.

Look-alikes

• Lamellar macular hole and pseudohole (OCT distinguishes them).
• Vitreomacular traction.
• Cystoid macular oedema.

Test yourself: flip cards

Related: Macular Hole Staging: Gass vs IVTS Classification, OCT Macula Reference Card: Normal Thickness, DME and Hole Staging, Retinal Layers and OCT Made Easy: Where Every Lesion Sits.

Key sources

• Govetto A, et al. Insights into epiretinal membranes: presence of ectopic inner foveal layers and a new optical coherence tomography staging scheme. Am J Ophthalmol. 2017;175:99-113
• American Academy of Ophthalmology. Idiopathic Epiretinal Membrane and Vitreomacular Traction Preferred Practice Pattern (current edition)