title: Retinal vessel diameter changes in different severities of diabetic retinopathy by SD-OCT.
abstract: OBJECTIVE
  To evaluate retinal vessel diameters in relation to different severity grades of diabetic retinopathy (DR) using spectral-domain optical coherence tomography (SD-OCT).
  
  
  METHODS
  Patients with varying degrees of nonproliferative DR (NPDR) underwent circular OCT scans centered on the optic nerve head using a SD-OCT. These cases were retrospectively reviewed. The presence and severity of DR was assessed using Early Treatment Diabetic Retinopathy Study protocols. The 5 largest retinal arterioles and venules were labeled and measured on OCT scans for each patient according to previously published methods. Vertical vessel inner contour diameter, vertical vessel outer contour diameter, and reflectance shadowing width were among the documented parameters.
  
  
  RESULTS
  Of 59 eyes from 45 patients examined, 30 (50.2%) and 29 (49.8%) had mild and severe NPDR, respectively. Eyes with severe NPDR had narrower mean arteriolar vertical vessel inner diameter (87.9 ± 10.8 μm), vertical vessel outer diameter (119.1 ± 9.7 μm), and vessel shadow width (78.8 ± 10.9 μm) than eyes with mild NPDR (89.8 ± 12.1 μm, 120.9 ± 12.9 μm, 81.3 ± 15.3 μm). However, the differences were not statistically significant (p = 0.53, 0.55, 0.47). No correlation was shown between the severity of NPDR and arteriolar parameters (p = 0.31, 0.59, 0.75). Wider venular diameters were associated with increasing severity of NPDR (p&lt;0.001, &lt;0.001, 0.007, respectively). The association remained after multivariate adjustment for age, sex, eye, and cataract surgery (p = 0.04, 0.01, 0.007, respectively).
  
  
  CONCLUSIONS
  Wider retinal venule diameter was significantly associated with the severity of NPDR by SD-OCT-assisted measurement. Prospective studies would be needed to evaluate whether change in retinal venule could be used as a clinical indicator of DR progression.
authors.affiliation: Charité-Universitätsmedizin Berlin, Department of Ophthalmology, Berlin - Germany.
authors.forename: Qing
authors.initials: Q
authors.lastname: Shao
authors.affiliation: Department of Ophthalmology, Royal Liverpool University Hospital, Liverpool - UK.
authors.forename: Florian M
authors.initials: FM
authors.lastname: Heussen
authors.affiliation: Charité-Universitätsmedizin Berlin, Department of Ophthalmology, Berlin - Germany.
authors.forename: Yanling
authors.initials: Y
authors.lastname: Ouyang
authors.affiliation: Charité-Universitätsmedizin Berlin, Department of Ophthalmology, Berlin - Germany.
authors.forename: Annette
authors.initials: A
authors.lastname: Hager
mesh_terms: D000328:Adult; D000368:Aged; D003924:Diabetes Mellitus, Type 2 / Q000150:complications; D003930:Diabetic Retinopathy / Q000145:classification* / Q000175:diagnosis*; D005260:Female; D005451:Fluorescein Angiography; D006801:Humans; D008297:Male; D008875:Middle Aged; D012161:Retinal Artery / Q000473:pathology*; D012169:Retinal Vein / Q000473:pathology*; D012189:Retrospective Studies; D012720:Severity of Illness Index; D041623:Tomography, Optical Coherence / Q000379:methods