title: Quantitative and qualitative retinal microvascular characteristics and blood pressure.
abstract: OBJECTIVE
  The present study examined the effects of blood pressure on a spectrum of quantitative and qualitative retinal microvascular signs.
  
  
  METHODS
  Retinal photographs from the Singapore Malay Eye Study, a population-based cross-sectional study of 3280 (78.7% response) persons aged 40-80 years, were analyzed. Quantitative changes in the retinal vasculature (branching angle, vascular tortuosity, fractal dimension, and vascular caliber) were measured using a semi-automated computer-based program. Qualitative signs, including focal arteriolar narrowing (FAN), arteriovenous nicking (AVN), opacification of the arteriolar wall (OAW), and retinopathy (e.g., microaneurysms, retinal hemorrhages), were assessed from photographs by trained technicians. After excluding persons with diabetes and ungradable photographs, 1913 persons provided data for this analysis.
  
  
  RESULTS
  In multivariable linear regression models controlling for age, sex, BMI, use of antihypertensive medication, and other factors, retinal arteriolar branching asymmetry ratio, arteriolar tortuosity, venular tortuosity, fractal dimension, arteriolar caliber, venular caliber, FAN, AVN, and retinopathy were independently associated with mean arterial blood pressure. In contrast, arteriolar/venular branching angle, venular branching asymmetry ratio and OAW were not related to blood pressure. Retinal arteriolar caliber (sβ = -0.277) and FAN (sβ = 0.170) had the strongest associations with mean arterial blood pressure, and higher blood pressure levels were associated with increasing number of both quantitative and qualitative retinal vascular signs (P trend <0.001).
  
  
  CONCLUSIONS
  Elevated blood pressure is associated with a spectrum of quantitative and qualitative retinal vascular signs, with the number of signs increasing with higher blood pressure levels.
authors.affiliation: Singapore Eye Research Institute, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore. carol.cheung.y.l@seri.com.sg
authors.forename: Carol Y
authors.initials: CY
authors.lastname: Cheung
authors.forename: Wan T
authors.initials: WT
authors.lastname: Tay
authors.forename: Paul
authors.initials: P
authors.lastname: Mitchell
authors.forename: Jie J
authors.initials: JJ
authors.lastname: Wang
authors.forename: Wynne
authors.initials: W
authors.lastname: Hsu
authors.forename: Mong L
authors.initials: ML
authors.lastname: Lee
authors.forename: Qiangfeng P
authors.initials: QP
authors.lastname: Lau
authors.forename: Ai L
authors.initials: AL
authors.lastname: Zhu
authors.forename: Ronald
authors.initials: R
authors.lastname: Klein
authors.forename: Seang M
authors.initials: SM
authors.lastname: Saw
authors.forename: Tien Y
authors.initials: TY
authors.lastname: Wong
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001794:Blood Pressure; D003430:Cross-Sectional Studies; D006801:Humans; D008296:Malaysia; D008875:Middle Aged; D012171:Retinal Vessels / Q000502:physiology*