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).
Conclusion: 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.
aSingapore Eye Research Institute, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
bCentre for Vision Research, University of Sydney, Sydney, Australia
cCentre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, University of Melbourne, Melbourne, Victoria, Australia
dSchool of Computing, National University of Singapore, Singapore, Singapore
eDepartment of Ophthalmology, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin, USA
fDepartment of Epidemiology and Public Health, Singapore
gDepartment of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
Received 2 December, 2010
Revised 15 March, 2011
Accepted 25 March, 2011
Correspondence to Dr Carol Y. Cheung, Singapore Eye Research Institute, 11 Third Hospital Avenue, Singapore 168751, Singapore Tel: +65 6322 4575; fax: +65 6323 1903; e-mail: firstname.lastname@example.org