Epiretinal Membrane Workup

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

Imaging Studies

Fluorescein angiography

Performing an angiogram in cases of epiretinal membranes (ERMs) does not contribute anything significant in its diagnosis since the clinical picture is often specific enough. In less advanced cases, the angiographic picture is basically unremarkable. More significant findings, such as vessel tortuosity and macular edema, may be seen in more advanced cases.

Perform fluorescein angiography to rule out other lesions that may mimic epiretinal membranes.

Macular holes typically show early background fluorescence through the hole that disappears in the later phases.

Epiretinal membranes with pseudoholes typically do not exhibit this fluorescence since normal retinal tissue exists in the area.

An exudative macular degeneration also may mimic the appearance of an epiretinal membrane, but its angiographic picture of early fluorescence and leakage is easily distinguishable from epiretinal membranes.

Fluorescein angiograms of epiretinal membranes can reveal subtle leakage of the perifoveal capillaries or evidence of ischemia due to capillary dropout, which can assist with counseling for postoperative expectations. See the image below.

Fluorescein angiogram demonstrating retinal vascul Fluorescein angiogram demonstrating retinal vascular distortion. Note the leakage of the dye in the macular area, which represents secondary macular edema.

Ocular coherence tomography

Ocular coherence tomography (OCT) can elucidate the presence or absence of an epiretinal membrane.

OCT can objectively measure other effects of the epiretinal membrane on the retina, such as macular thickening, presence or absence of macular edema (eg, cystoid macular edema), and any associated vitreous traction on the retina.

Rouvas et al monitored patients with nontractional epiretinal membrane over time and demonstrated stability of visual acuity. They defined nontractional epiretinal membranes as membranes noted to have a tear or discontinuity on at least one line of the OCT scan. The mean follow-up period was 38.2 months, and 84.4% of patients were noted to have improvement or stabilization of visual acuity at the end of follow-up. The authors suggest that patients with nontractional epiretinal membranes may safely be monitored over follow–up, deferring surgery. [7]

OCT allows the monitoring of the postoperative return of the normal retinal architecture as well as the presence of persistent traction or folds of the retina.

Evaluation of the inner-segment/outer-segment (IS/OS) junction on OCT appears to be correlated with postoperative visual acuity. [3] Hosoda et al also identified that the degree of photoreceptor deformation was predictive of postoperative visual acuity. They described a "photoreceptor deformation index" based on characteristics on the OCT. [8]

Gupta et al used combined OCT/scanning laser ophthalmoscopy (SLO) to evaluate 44 consecutive eyes with epiretinal membrane. [9] Of the patients evaluated, 20 out of 44 demonstrated multiple foci of contracture within the epiretinal membrane. They subdivided epiretinal membrane into “simple puckers" and “complex puckers.” Complex puckers had a higher rate of intraretinal cysts and macular thickening than simple puckers. However, no difference in visual dysfunction existed between the two groups; the authors hypothesize that architectural differences in the retina may precede visual acuity loss.

Kromer et al correlated high preoperative retinal volumes on OCT with more benefit from surgical interval. They suggested that increased volumes were related to increased tractional components on the retina. [10]