title: The relationship between foveal ischemia and spectral-domain optical coherence tomography findings in ischemic diabetic macular edema.
abstract: OBJECTIVE
  To investigate the relationship between enlargement of the foveal avascular zone (FAZ) and structural changes on spectral-domain optical coherence tomography (SD-OCT) in patients with ischemic diabetic macular edema (DME).
  
  
  METHODS
  This was a retrospective, cross-sectional study including 35 eyes of 33 patients with ischemic DME as determined by irregular margins of the FAZ in fluorescein angiography. We measured the best-corrected visual acuity (BCVA), central subfield thickness (CST), subfield volume, subfoveal choroidal thickness, length of the photoreceptor outer segment (PR-OS), and the lateral extent of inner segment-outer segment (IS-OS) disruption on SD-OCT images, as well as the FAZ to optic nerve head (FAZ/ONH) area ratio by using the ImageJ program.
  
  
  RESULTS
  The mean FAZ/ONH area ratio was 0.28 ± 0.15. The FAZ/ONH area ratio was positively correlated with the logarithm of the minimum angle of resolution (LogMAR) BCVA (P = 0.001, r = 0.529). The mean CST was 391 ± 110 μm, and the subfield volume was 0.31 ± 0.09 mm(3). The mean length of the PR-OS and the horizontal and vertical extent of IS-OS disruption were 40 ± 8 μm, 169 ± 294 μm, and 114 ± 170 μm, respectively. The mean length of the PR-OS and the horizontal and vertical extent of IS-OS disruption were significantly correlated with FAZ/ONH area ratio (P = 0.020, P = 0.001, and P = 0.049, respectively). The horizontal and vertical extent of IS-OS disruption showed a positive correlation with LogMAR BCVA (P = 0.027 and P = 0.049, respectively).
  
  
  CONCLUSIONS
  Foveal ischemia in DME appears to cause PR-OS shortening and IS-OS disruption resulting in outer retinal layer atrophic changes and subsequent visual loss.
authors: Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
authors: Dong-Hoon
authors: DH
authors: Lee
authors: Jee Taek
authors: JT
authors: Kim
authors: Da-Woon
authors: DW
authors: Jung
authors: Soo Geun
authors: SG
authors: Joe
authors: Young Hee
authors: YH
authors: Yoon
mesh_terms: D000328:Adult; D000368:Aged; D002829:Choroid / Q000473:pathology; D003430:Cross-Sectional Studies; D003930:Diabetic Retinopathy / Q000175:diagnosis* / Q000209:etiology; D005260:Female; D005451:Fluorescein Angiography; D005584:Fovea Centralis / Q000098:blood supply / Q000473:pathology*; D006801:Humans; D007511:Ischemia / Q000175:diagnosis* / Q000209:etiology; D008269:Macular Edema / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D009898:Optic Disk / Q000473:pathology; D055211:Retinal Photoreceptor Cell Inner Segment / Q000473:pathology; D055214:Retinal Photoreceptor Cell Outer Segment / Q000473:pathology; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence; D014792:Visual Acuity / Q000502:physiology; D055815:Young Adult