Epiretinal Membrane Clinical Presentation

Updated: Aug 28, 2018
  • Author: Kean Theng Oh, MD; Chief Editor: Douglas R Lazzaro, MD, FAAO, FACS  more...
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Presentation

History

The type and degree of symptoms experienced by an individual with epiretinal membrane (ERM) depends largely on the thickness of the membrane, the degree of retinal distortion it causes, the location of the wrinkling, and the presence or the absence of retinal detachment or edema. [5]

The usual symptoms caused by epiretinal membranes run the spectrum from no symptoms at all to severe visual dysfunction.

Early on, epiretinal membranes cause little or no visual disturbance.

As the membrane progresses, the visual disturbance is often vague and difficult for the patient to describe.

Mild distortion or blurring is the most common symptom.

Vision better than 20/50 is present in 78-85% of cases, while 56-67% have vision better than 20/30. Only 2-5% have vision poorer than 20/200.

In more advanced cases, metamorphopsia, micropsia, or Amsler Grid abnormalities may be present.

In contrast, vision is markedly reduced in patients with epiretinal membranes associated with retinal detachment. Vision is 20/60 or better in only 7% of cases and 56% have vision poorer than 20/200 after successful retinal reattachment surgery.

In a 2016 preferred practice guideline for epiretinal membranes, the authors reported that, over a 5-year period, 29% of epiretinal membranes progressed, 26% regressed, and 39% remained stable. [3]

Use of spectral domain ocular coherence tomography (SD-OCT) has correlated inner nuclear layer thickness with the symptom of metamorphopsia. Ichikawa et al suspect that tangential retinal displacement distorting Muller cells results in metamorphopsia. [6]

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Physical

The clinical findings in epiretinal membranes vary according to the degree of severity of the membrane. Gass formulated a classification system based on the appearance of the membrane and the underlying retinal tissue and vessels. This grading system is not typically used in clinical practice, but it is interesting from a historical perspective.

Grade 0 membranes

Grade 0 epiretinal membranes are translucent membranes not associated with any retinal distortion.

These epiretinal membranes also are known as cellophane maculopathy owing to the cellophanelike sheen coming from the inner retinal surface as it is seen ophthalmoscopically.

Grade 1 membranes

Membranes causing an irregular wrinkling of the inner retinal surface are classified as grade 1 epiretinal membranes.

The crinkled cellophane appearance is caused by the gathering of the inner retinal layers into folds following the contraction of the overlying membrane.

Fine, superficial, radiating folds extend outward from the margins of the contracted membrane.

Wrinkling may be sufficient to produce tortuosity of the paramacular vessels pulling them toward the fovea.

Cystoid macular edema, retinal hemorrhage, exudates, and RPE disturbances are typically absent.

Grade 2 membranes

Membranes, especially those that develop after retinal detachment surgery, have an opaque, thick appearance.

Gross, full-thickness puckering of the macula may be present along with retinal edema, small hemorrhages, cotton-wool spots, and, infrequently, a localized detachment of the retina.

These membranes are labeled macular puckers or grade 2 membranes.

Pseudoholes

A pseudohole is depicted in the image below.

Grade 2 epiretinal membrane causing striations in Grade 2 epiretinal membrane causing striations in the retinal surface. Note the presence of a pseudohole.
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Causes

See Pathophysiology.

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