Ellipsoid Zone Mapping Parameters in Retinal Venous Occlusive Disease with Associated Macular Edema

Purpose: To evaluate the association of baseline ellipsoid zone (EZ) parameters on OCT as calculated by a semiautomated computer algorithm with baseline visual acuity (VA) in eyes with retinal vein occlusion (RVO). Design: Retrospective, consecutive case series. Participants: Patients affected by RVO treated from January 2011 through December 2014. Methods: Baseline demographics, clinical characteristics, and spectral-domain OCT data at presentation were collected. Macular cube scans were exported into a retinal layer analysis software platform and outer retinal parameters were evaluated. Outer retinal and EZ parameters included EZ–retinal pigment epithelium (RPE) volume, central foveal EZ–RPE area, EZ–RPE central subfield thickness (CST), and EZ–RPE central foveal thickness. In addition, en face EZ mapping features were extracted, including percent area with EZ attenuation (i.e., EZ–RPE thickness <20 μm) and percent area with total EZ loss (i.e., EZ–RPE thickness of 0 μm). Main Outcome Measure: Correlation of EZ parameters and baseline VA. Secondary outcome measures included correlation of EZ parameters with other clinical characteristics and OCT measures of cube volume (CV), cube average thickness (CAT), and CST. Results: This analysis included 112 eyes. Mean baseline VA was 56.53±17.68 Early Treatment Diabetic Retinopathy letters and was associated inversely with total EZ loss and EZ–RPE attenuation (r = −0.33 and −0.38 respectively; P < 0.001). Visual acuity was associated directly with all other EZ parameters (r = 0.37–0.45; P < 0.001). The presence of subretinal fluid was linked strongly to central parameters of central foveal EZ–RPE, EZ–RPE CST, and EZ–RPE central foveal thickness (Kruskal-Wallis test). Conventional OCT parameters (CST, CV, and CAT) did not have significant correlations with EZ measures (−0.3 < R < 0.3, P > 0.05, or both). Conclusions: Baseline EZ integrity is linked closely to presenting VA in eyes with RVO and macular edema. Ellipsoid zone mapping provides an additional metric for evaluating RVO impact on retinal anatomic features and potential function.