title: Associations of retinal oximetry in persons with diabetes.
abstract: BACKGROUND
  There are limited data available on the variables that might affect retinal vessel oxygen saturation (SO₂) in diabetes. Therefore, the aim of this study is to assess factors associated with retinal oximetry values in persons with diabetes.
  
  
  METHODS
  Clinic-based cross-sectional study.
  
  
  METHODS
  Fifty-eight persons with diabetes aged 18+ years, recruited from the University of Melbourne, the Royal Victorian Eye and Ear Hospital, and St. Vincent's Hospital (Melbourne), Australia.
  
  
  METHODS
  Retinal oximetry was performed using the oximetry module of the Vesselmap system (Imedos UG, Jena, Germany) in 92 diabetic eyes. Generalized estimating equation models were used to estimate the associations between candidate variables (age; gender; retinal capillary flow; duration of diabetes; hypertension; smoking status; presence of diabetic retinopathy [DR]; glycated haemoglobin; triglyceride; total cholesterol; finger SO₂ and ocular perfusion pressure) with retinal oximetry measures.
  
  
  METHODS
  Arteriolar SO₂, venular SO₂ and the arterio-venous (A-V) difference.
  
  
  RESULTS
  Of the candidate factors assessed, only the presence of DR was significantly associated with increased venular SO₂ and decreased A-V difference in unadjusted analyses. In models adjusting for age and gender and significant variables from unadjusted analyses, compared with no DR, the presence of DR was significantly associated with greater retinal venular SO₂ values (β = 3.65%, 95% confidence interval: 0.67-6.63%) and decreased A-V difference (β = -2.00%, 95% confidence interval: -3.46 to -0.53%).
  
  
  CONCLUSIONS
  In patients with diabetes, eyes with DR were associated with increased venular SO₂ and decreased A-V difference compared with eyes without DR, suggesting an altered metabolic state in DR.
authors.affiliation: Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Victoria.
authors.forename: Ryan E K
authors.initials: RE
authors.lastname: Man
authors.forename: Muhammad B
authors.initials: MB
authors.lastname: Sasongko
authors.forename: Jing
authors.initials: J
authors.lastname: Xie
authors.forename: Ryo
authors.initials: R
authors.lastname: Kawasaki
authors.forename: William J
authors.initials: WJ
authors.lastname: Best
authors.forename: Jonathan E
authors.initials: JE
authors.lastname: Noonan
authors.forename: Chi D
authors.initials: CD
authors.lastname: Luu
authors.forename: Jie Jin
authors.initials: JJ
authors.lastname: Wang
authors.forename: Ecosse L
authors.initials: EL
authors.lastname: Lamoureux
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D001794:Blood Pressure; D002784:Cholesterol / Q000097:blood; D003430:Cross-Sectional Studies; D003920:Diabetes Mellitus / Q000503:physiopathology*; D003930:Diabetic Retinopathy / Q000503:physiopathology*; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D007429:Intraocular Pressure; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010100:Oxygen / Q000097:blood*; D012171:Retinal Vessels / Q000502:physiology*
chemical_list: D002784:Cholesterol; D006442:Glycated Hemoglobin; D010100:Oxygen; C517652:hemoglobin A1c protein, human
keywords: diabetes; diabetic retinopathy; oxygen saturation; retinal oximetry; retinal vasculature