OCTA defines specific characteristics of epiretinal membranes in retinal vein occlusion
FORT LAUDERDALE, Fla. — Epiretinal membranes, or ERMs, in retinal vein occlusion do not share the same OCT angiography characteristics described for idiopathic ERMs but instead reflect the changes typical of vascular pathologies.
A study presented at the Retina World Congress looked for the first time at these specific features.
“Previous reports have shown that the probability to develop ERM within 24 months is 19.5% in nonischemic [central retinal vein occlusion], 25% in ischemic CRVO and 8.6% in [branch retinal vein occlusion]. In our study, we retrospectively reviewed OCTA images captured with the AngioVue imaging system (Optovue) in 33 eyes of 33 patients with RVO of all types, most commonly CRVO,” Francisco J. Rodríguez, MD, said.
B-scan morphological findings showed that the mean central retinal thickness was 327 µm, and there was no foveal involvement by the ERM in the majority of patients. The pattern of adherence of ERM to the retinal surface was classified as mixed in 45.5% of the patients, global in 42.4% and focal in 12.1%. Intraretinal cystoid spaces were present in 60.6% of the eyes. Ectopic inner foveal layers were present in 12%, and disorganization of the retinal inner layers was present in 42.4%. Rodríguez also said that disruption of the external limiting membrane (ELM) was present in 60.6% and disruption of the ellipsoid zone (EZ) in 66.7%.
“We also used the en face imaging to see the pattern of the ERM, and the most common was the so-called not defined or ‘plaque’ pattern in 42.2% of the eyes,” he said.
Changes in foveal avascular zone (FAZ) were mostly generated by contraction of the ERM. The FAZ was measured automatically and was on average 280 mm2 in size, while the FAZ nonflow was 676 mm2. Macular vascular density was 0.67 in both the superficial and deep capillary plexus. A nonperfusion area was present in 91% of eyes in the superficial capillary plexus and 88% of eyes in the deep capillary plexus.
“Most ERMs in RVO respect the foveal area with a slight tendency to the adherence pattern to the global surface type,” Rodríguez said. “Disruption of the ELM and EZ may be associated with worse visual outcome.”
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Rodríguez FJ, et al. Characterization of epiretinal membrane in retinal vein occlusion using OCTA. Presented at: Retina World Congress; May 12-15, 2022; Fort Lauderdale, Fla.
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