title: Classification of diabetic macular oedema using ultra-widefield angiography and implications for response to anti-VEGF therapy.
abstract: To characterise differential pathogeneses of diabetic macular oedema (DMO) using ultra-widefield fluorescein angiography (UWFA) and evaluate responses to anti-vascular endothelial growth factor (anti-VEGF) therapy.
  
  
  
  Ninety-nine eyes (73 consecutive patients) with anti-VEGF naïve DMO underwent UWFA and optical coherence tomography, of which 60 with central retinal thickness (CRT) >400 μm received monthly intravitreal ranibizumab injections. Best-corrected visual acuity (BCVA) and CRT were measured at baseline and after three injections.
  
  
  
  After excluding tractional factors, DMO was categorised into three types based on UWFA: (A) microaneurysm driven (49%), (B) peripheral ischaemia (37%) and (C) neovascularisation (15%). While all three types showed similar mean CRT (p=0.257), types B and C were associated with more diffuse oedema, which extended beyond the 6.0 mm central macula (p=0.0034). Following anti-VEGF treatment, all three types showed improvement in CRT and BCVA, which reached statistical significance for types A and B. A positive correlation was found between the Peripheral Ischaemia Index and improvement in CRT (slope=2.09, R2=0.1169, p=0.0151) but not BCVA (slope=-0.00037, R2=0.001149, p=0.8152).
  
  
  
  UWFA facilitates the detection of peripheral ischaemia, which is associated with a significant proportion of DMO. While this group of DMO responded well to anti-VEGF therapy, it remains to be determined whether addressing the peripheral ischaemia may reduce recurrence.
authors.affiliation: Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK.|Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
authors.forename: Kanmin
authors.initials: K
authors.lastname: Xue
authors.affiliation: Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Yang
authors.affiliation: Oxford Eye Hospital, Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
authors.forename: N Victor
authors.initials: NV
authors.lastname: Chong
mesh_terms: D000368:Aged; D020533:Angiogenesis Inhibitors / Q000627:therapeutic use*; D003930:Diabetic Retinopathy / Q000145:classification* / Q000175:diagnosis / Q000188:drug therapy*; D005260:Female; D005451:Fluorescein Angiography / Q000379:methods*; D006801:Humans; D058449:Intravitreal Injections; D007511:Ischemia / Q000175:diagnosis; D008269:Macular Edema / Q000145:classification* / Q000175:diagnosis / Q000188:drug therapy*; D008297:Male; D008875:Middle Aged; D000069579:Ranibizumab / Q000627:therapeutic use*; D015861:Retinal Neovascularization / Q000175:diagnosis; D012189:Retrospective Studies; D041623:Tomography, Optical Coherence; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors; D014792:Visual Acuity
chemical_list: D020533:Angiogenesis Inhibitors; D042461:Vascular Endothelial Growth Factor A; D000069579:Ranibizumab
keywords: Diagnostic tests/Investigation; Imaging; Macula; Retina; Treatment Medical