Epiretinal Membrane

An epiretinal membrane is a fibrocellular layer on the inner retinal surface that contracts and distorts the macula (macular pucker). Prevalence is 7 to 12% in people over 50 and about 20% over 75, and 20 to 30% are bilateral. About 80% are idiopathic, related to posterior vitreous detachment with Müller cell and hyalocyte proliferation. Secondary causes are retinal tear or detachment surgery, retinal vein occlusion, uveitis, diabetic retinopathy, trauma and laser.

Optical coherence tomography stages: 1 membrane with preserved foveal pit, 2 loss of the foveal pit, 3 ectopic inner foveal layers, 4 disorganized retinal layers. Most membranes stay stable. About 15 to 30% progress, and 2 to 5% separate spontaneously. Complications are cystoid macular edema, lamellar hole and pseudohole.

• Metamorphopsia, blurring, micropsia and monocular diplopia
• Acuity from normal to 20/200
• A glistening cellophane reflex, retinal folds, tortuous retinal vessels and a pseudohole
• Cystoid macular edema in some
• Red flags: rapid decline, signs of a secondary cause, or hemorrhage

• Optical coherence tomography is first line. It shows a hyperreflective inner layer with retinal thickening and stage.
• Amsler grid or M-charts to quantify distortion.
• Fundus autofluorescence and fluorescein angiography when a secondary cause or vascular leak is suspected.
• Peripheral retinal examination to exclude a tear.

Differentials: macular hole, lamellar hole, vitreomacular traction, cystoid macular edema, choroidal neovascularization, central serous chorioretinopathy.

Observation: mild symptoms with acuity 20/40 or better.

Surgery for acuity 20/40 or worse or disabling distortion:

• 23 to 27 gauge pars plana vitrectomy with membrane peeling, and internal limiting membrane peeling with brilliant blue G 0.025% to reduce recurrence (about 10% without, 1% with). No long acting gas is needed.
• Combined phacoemulsification and vitrectomy in patients over 60 with a cataract.
• Outcomes: acuity gains of 2 to 3 lines in 60 to 70%. Metamorphopsia improves less, and earlier surgery gives better results.

Complications: cataract (up to 80% of phakic eyes within 2 years), retinal tear (1 to 6%), detachment (1 to 2%), endophthalmitis (about 0.05%), cystoid macular edema, recurrence.

Postoperative drops: moxifloxacin 0.5% four times daily for 1 week, prednisolone 1% four times daily tapering over 4 weeks, and nepafenac 0.1% three times daily for 4 weeks in diabetic patients.

Follow up on day 1, week 1 to 2, week 6 and month 3. Counsel that distortion may persist for months to a year.