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

Abstract

Baseline EZ integrity is closely linked to presenting visual acuity in eyes with RVO and macular edema. EZ mapping provides an additional metric for evaluating RVO impact on retinal anatomy and potential function.

A semi-automated machine-learning based workflow for ellipsoid zone analysis in eyes with macular edema: SCORE2 pilot study

“…Similar approaches to evaluating EZ integrity exclude patients with severe edema, which has been defined as a CSF thickness greater than 600 μm. [5] Although we did not use this threshold, we did exclude EZ defect area measurements less than or equal to 0.004 mm 2 . Area measurements less than this value were considered absent.…”

“…[2] SD-OCT enables in vivo high-resolution, cross-sectional imaging of the retina, permitting qualitative and quantitative assessment of EZ integrity, which has been correlated with VA in multiple retinal diseases, [3,4] including retinal vein occlusion (RVO). [5][6][7] Many studies examining the EZ layer are qualitative, describing abnormalities of the layer based on signal intensity. [8,9] Current methods for quantitative assessment of the EZ involve segmentation of the retinal layers using manual or semi-automated techniques.…”

“…An alternative and more intuitive method would be to assess the area of EZ defect or loss using en face thickness maps created from the segmented layers. [5] The en face maps are two dimensional and present areas of EZ absence, i.e. very low thickness areas are dark regions against a brighter background of normal EZ thickness.…”

Deep longitudinal transfer learning-based automatic segmentation of photoreceptor ellipsoid zone defects on optical coherence tomography images of macular telangiectasia type 2

“…There is an ongoing lively debate regarding the exact cellular structure that correlates with this hyper-reflective band and the nomenclature used to describe it. Recent publications [ 10 – 16 ], including that from a consensus International Nomenclature group [ 17 ], refer to this band as the ellipsoid zone (EZ) as it is thought to represent the ellipsoid region of the photoreceptor inner segments which have densely-packed mitochondria that are likely hyper-reflective on OCT [ 18 ]. However, other studies, including a recent one that used adaptive optics to characterize this structure [ 9 ], refer to it as the junction between the inner segments and outer segments (IS/OS) of the photoreceptors [ 2 – 4 , 8 , 19 – 22 ].…”

“…EZ defects are also observed in other retinal diseases such as age-related macular degeneration (AMD) [ 22 ], macular edema (ME) [ 10 ], and diabetic retinopathy (DR) [ 11 ]. Semi-automatic EZ defects analysis has also been performed in these diseases [ 10 , 12 , 29 ].…”