title: Quantification of changes in foveal capillary architecture caused by idiopathic epiretinal membrane using OCT angiography.
abstract: OBJECTIVE
  To quantify the extent and depth of distortion of the foveal capillary architecture due to traction of an idiopathic epiretinal membrane (ERM) using optical coherence tomography angiography (OCT-A).
  
  
  METHODS
  Multimodal imaging including OCT-A (Angiovue, Optovue) was performed in 42 eyes with idiopathic ERM (72.4 years ±6.8). Best corrected visual acuity (BCVA), OCT-A vessel density of the foveal (VDfo) and parafoveal (VDp) region were assessed. Based on 6 × 6-mm2OCT-A images, a macular vessel density ratio (MVR = VDfo/VDp) was calculated for the superficial (s), deep (d) and full-thickness (f) slabs to assess a depth-resolved, non-invasive evaluation of foveal distortion. The acquired data were subdivided in a patient group with mild and significant BCVA reduction due to ERM. Data was compared to age-matched healthy controls.
  
  
  RESULTS
  In all three slabs, MVR was significantly smaller in the control group in comparison with the ERM group: MVRs: 0.63 ± 0.1 vs 0.83 ± 0.1 (p > 0.001); MVRd: 0.60 ± 0.1 vs 0.73 ± 0.1 (p < 0.001); MVRf: 0.68 ± 0.1 vs 0.82 ± 0.1 (p < 0.001). Group 1 (BCVA <0.4 LogMar) showed a significantly higher MVR in comparison with the control group in the superficial plexus only: MVRs: 0.64 ± 0.1 vs 0.78 ± 0.1 (p < 0.001); MVRd: 0.60 ± 0.1 vs 0.65 ± 0.2 (p = 0.3); MVRf: 0.68 ± 0.1 vs 0.77 ± 0.1 (p = 0.01). However, group 2 (BCVA > = 0.4 LogMar) showed a significantly higher MVR in all three slabs: MVRs: 0.64 ± 0.1 vs 0.86 ± 0.1 (p < 0.001); MVRd: 0.60 ± 0.1 vs 0.77 ± 0.2 (p < 0.001); MVRf: 0.68 ± 0.1 vs 0.85 ± 0.1 (p < 0.001).
  
  
  CONCLUSIONS
  Assessing MVR using OCT-A may serve as a tool to quantify the extent and depth of distortion of the foveal capillary architecture due to traction of ERM. BCVA reduction appears to be associated with extent and depth of distortion.
authors.affiliation: Department of Ophthalmology, University of Muenster Medical Center, Albert-Schweitzer-Campus 1, Building D15, 48149, Muenster, Germany. pieter.nelis@ukmuenster.de.
authors.forename: P
authors.identifier: http://orcid.org/0000-0001-8616-9664
authors.initials: P
authors.lastname: Nelis
authors.affiliation: Department of Ophthalmology, University of Muenster Medical Center, Albert-Schweitzer-Campus 1, Building D15, 48149, Muenster, Germany.
authors.forename: F
authors.initials: F
authors.lastname: Alten
authors.affiliation: Department of Ophthalmology, University of Muenster Medical Center, Albert-Schweitzer-Campus 1, Building D15, 48149, Muenster, Germany.
authors.forename: C R
authors.initials: CR
authors.lastname: Clemens
authors.affiliation: Department of Ophthalmology, University of Muenster Medical Center, Albert-Schweitzer-Campus 1, Building D15, 48149, Muenster, Germany.
authors.forename: P
authors.initials: P
authors.lastname: Heiduschka
authors.affiliation: Department of Ophthalmology, University of Muenster Medical Center, Albert-Schweitzer-Campus 1, Building D15, 48149, Muenster, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Eter
mesh_terms: D000368:Aged; D002196:Capillaries / Q000473:pathology; D019773:Epiretinal Membrane / Q000175:diagnosis* / Q000503:physiopathology; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D005500:Follow-Up Studies; D005584:Fovea Centralis / Q000098:blood supply*; D005654:Fundus Oculi; D006801:Humans; D008297:Male; D011446:Prospective Studies; D012171:Retinal Vessels / Q000473:pathology*; D041623:Tomography, Optical Coherence / Q000379:methods*; D014792:Visual Acuity
keywords: Epiretinal membrane; OCT angiography; Quantification; Vessel density