Epiretinal Membrane

Clinical Presentation

Epiretinal membranes (ERMs) typically cause slowly progressive, painless metamorphopsia with mild-to-moderate decreased visual acuity. The mechanism is tangential traction on the macula, not any acute event, which is why the presentation lacks the sudden vision loss, pain, or photopsia that would instead point toward a vascular or inflammatory process.

Grading

ERM severity spans a spectrum from subtle to markedly contractile. An early, thin membrane produces only a glistening inner retinal light reflex with little real distortion, termed cellophane maculopathy for its resemblance to cellophane wrap. Traction is minimal at this stage, and symptoms are often absent entirely. As the membrane thickens and contracts, retinal wrinkling worsens, the normal foveal depression flattens, and striae and thickening develop that correlate with genuine visual distortion.

Imaging

On OCT, an ERM appears as a thin hyperreflective line adherent to the inner retinal surface, often with loss of the normal foveal contour, visible retinal striae, and increased retinal thickness from the tangential pull. OCT also distinguishes a contracted ERM from other causes of macular thickening and identifies the pseudohole appearance described below.

Surgical Treatment

Asymptomatic or mildly symptomatic membranes are managed with observation and serial monitoring; a membrane visible on exam is not, by itself, a reason to operate. Once traction produces significant visual distortion or decline, the standard treatment is pars plana vitrectomy with mechanical peeling of the membrane, often combined with internal limiting membrane peeling, to relieve the tangential traction driving the symptoms.

A pharmacologic alternative exists for the related problem of vitreomacular traction: ocriplasmin, an intravitreal enzymatic agent that cleaves fibronectin and laminin at the vitreoretinal interface to induce posterior vitreous detachment without surgery. It works best against focal vitreomacular adhesion, not a broad, already-contracted membrane, so it belongs more to the vitreomacular traction and small macular hole category than to established ERM, though both share the same underlying mechanism of abnormal vitreoretinal traction.

Macular Pseudohole

A severe, densely contracted ERM can pull retinal tissue centripetally hard enough to create a steep-walled foveal excavation that resembles a macular hole on clinical exam: a macular pseudohole. The distinction matters for counseling and surgical planning. On OCT, a pseudohole shows a continuous, intact photoreceptor layer beneath the steepened contour, where a true full-thickness macular hole shows an actual tissue gap. See the Macular Hole page for the staging and surgical approach to the full-thickness entity this one mimics.

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