EPIRETINAL MEMBRANE

SIGNS AND SYMPTOMS
Epiretinal membrane is known by many names in clinical and educational circles, including preretinal membrane, idiopathic preretinal macular gliosis, cellophane maculopathy, macular pucker and surface wrinkling retinopathy. In early stages, epiretinal membrane may be asymptomatic, or it may create only a mild reduction in acuity. Its progression may cause metamorphopsia and lead to severe visual impairment.

The ophthalmoscopic picture of this disorder ranges from a fine, glistening membrane overlying the macula (cellophane maculopathy) to a thickened, whitish tissue that obscures the underlying vasculature.

As the epiretinal membrane progresses, traction at the level of the internal limiting membrane (ILM) creates a puckering effect-you may see retinal folds radiating outward from the macula. Adjacent retinal vessels which course under the ILM often assume a "corkscrew" pattern, which is quite dramatic with fluorescein angiography. In very severe cases, macular edema and even retinal detachment have been known to occur.

PATHOPHYSIOLOGY
Epiretinal membrane formation occurs as a result of retinal glial cell proliferation along the surface of the ILM. Small, focal defects in the ILM allow these cells to "break through" to the retinal-vitreous interface and reproduce, creating a thin veil of tissue. Epiretinal membranes have been found in association with retinal vascular diseases, retinal breaks and detachments, ocular trauma, uveitis, and following retinal cryopexy, laser photocoagulation, and intraocular surgery. Often, the membranes are seen following posterior vitreous detachment, or they may occur idiopathically in patients over 50 years of age.

MANAGEMENT
In most cases, little can be done to improve acuity. Most patients, fortunately, suffer only a minimal reduction of acuity or slight metamorphopsia. Reassure patients as to the nature of the disorder and follow up periodically, using an Amsler grid for home monitoring of progression. In severe cases, vision may drop to 20/100 or worse; this may indicate the need for vitrectomy and surgical peeling of the membrane. This procedure is, as one might imagine, very intricate, and is reserved for those patients for whom there are no alternatives.

CLINICAL PEARLS

  • Suspect epiretinal membrane in older patients where decreased acuity or visual distortion cannot be accounted for by lenticular changes, macular degeneration or optic atrophy.

  • Early identification of epiretinal membranes requires careful inspection with a slit-lamp fundus lens (78D, Hruby or Goldmann). If you are confused as to the true etiology, or if you suspect macular edema, order a fluorescein angiography. Typical fluorescein patterns in epiretinal membrane show "corkscrew" distortion and dragging of the retinal vessels at the posterior pole, with a characteristic diminishing of the foveal avascular zone. If there's edema, you'll see hyperfluorescence within the macula during the late transitory phase.

Other reports in this section

Eyelids & Eyelashes | Conjunctiva & Sclera | Cornea
Uvea | Vitreous & Retina | Optic Nerve & Brain | Oculosystemic Disease

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