title: Flicker light-induced retinal vasodilation in diabetes and diabetic retinopathy.
abstract: OBJECTIVE
  Flicker light-induced retinal vasodilation may reflect endothelial function in the retinal circulation. We investigated flicker light-induced vasodilation in individuals with diabetes and diabetic retinopathy.
  
  
  METHODS
  Participants consisted of 224 individuals with diabetes and 103 nondiabetic control subjects. Flicker light-induced retinal vasodilation (percentage increase over baseline diameter) was measured using the Dynamic Vessel Analyzer. Diabetic retinopathy was graded from retinal photographs.
  
  
  RESULTS
  Mean +/- SD age was 56.5 +/- 11.8 years for those with diabetes and 48.0 +/- 16.3 years for control subjects. Mean arteriolar and venular dilation after flicker light stimulation were reduced in participants with diabetes compared with those in control subjects (1.43 +/- 2.10 vs. 3.46 +/- 2.36%, P < 0.001 for arteriolar and 2.83 +/- 2.10 vs. 3.98 +/- 1.84%, P < 0.001 for venular dilation). After adjustment for age, sex, diabetes duration, fasting glucose, cholesterol and triglyceride levels, current smoking status, systolic blood pressure, and use of antihypertensive and lipid-lowering medications, participants with reduced flicker light-induced vasodilation were more likely to have diabetes (odds ratio 19.7 [95% CI 6.5-59.1], P < 0.001 and 8.14 [3.1-21.4], P < 0.001, comparing lowest vs. highest tertile of arteriolar and venular dilation, respectively). Diabetic participants with reduced flicker light-induced vasodilation were more likely to have diabetic retinopathy (2.2 [1.2-4.0], P = 0.01 for arteriolar dilation and 2.5 [1.3-4.5], P = 0.004 for venular dilation).
  
  
  CONCLUSIONS
  Reduced retinal vasodilation after flicker light stimulation is independently associated with diabetes status and, in individuals with diabetes, with diabetic retinopathy. Our findings may therefore support endothelial dysfunction as a pathophysiological mechanism underlying diabetes and its microvascular manifestations.
authors.affiliation: Centre for Eye Research Australia, University of Melbourne, Melbourne, Victoria, Australia.
authors.forename: Thanh T
authors.initials: TT
authors.lastname: Nguyen
authors.forename: Ryo
authors.initials: R
authors.lastname: Kawasaki
authors.forename: Jie Jin
authors.initials: JJ
authors.lastname: Wang
authors.forename: Andreas J
authors.initials: AJ
authors.lastname: Kreis
authors.forename: Jonathan
authors.initials: J
authors.lastname: Shaw
authors.forename: Walthard
authors.initials: W
authors.lastname: Vilser
authors.forename: Tien Y
authors.initials: TY
authors.lastname: Wong
mesh_terms: D000328:Adult; D000368:Aged; D001160:Arterioles / Q000502:physiology / Q000503:physiopathology / Q000528:radiation effects; D002784:Cholesterol / Q000097:blood; D003920:Diabetes Mellitus / Q000097:blood / Q000503:physiopathology*; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000503:physiopathology; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology; D003930:Diabetic Retinopathy / Q000097:blood / Q000503:physiopathology*; D005425:Flicker Fusion / Q000502:physiology*; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D008027:Light; D008875:Middle Aged; D012016:Reference Values; D012160:Retina / Q000502:physiology* / Q000528:radiation effects; D012307:Risk Factors; D014280:Triglycerides / Q000097:blood; D014664:Vasodilation / Q000502:physiology / Q000528:radiation effects*; D014699:Venules / Q000502:physiology / Q000503:physiopathology / Q000528:radiation effects
chemical_list: D002784:Cholesterol; D006442:Glycated Hemoglobin; D014280:Triglycerides