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Updated: Aug 8, 2026
Fundus Photography as a Convenient Tool to Study Microvascular Responses to Cardiovascular Disease Risk Factors in Epidemiological Studies
Published on: October 22, 2014
Methods for evaluation of retinal microvascular abnormalities associated with hypertension/sclerosis in the
L D Hubbard1, R J Brothers, W N King
1ARIC Retinal Reading Center, Department of Ophthalmology & Visual Sciences, University of Wisconsin-Madison, 53705-2397, USA.
Insights
Retinal vascular abnormalities, including arteriolar narrowing and nicking, are linked to elevated blood pressure. These findings from the Atherosclerosis Risk in Communities study highlight potential links to cardiovascular disease.
Area of Science:
- Ophthalmology
- Cardiovascular Research
- Public Health
Background:
- Retinal microvascular changes can indicate systemic vascular health.
- The Atherosclerosis Risk in Communities (ARIC) Study provides a valuable dataset for exploring these associations.
Purpose of the Study:
- Develop and validate protocols for nonmydriatic fundus photography and retinal vascular abnormality grading.
- Investigate the relationship between retinal microvascular changes and blood pressure in a large cohort.
Main Methods:
- A population-based, cross-sectional study of 11,114 participants aged 48-73.
- Nonmydriatic fundus photography was used to assess focal arteriolar narrowing, AV nicking, and retinopathy.
- Quantitative measurements included arteriolar-to-venular (A/V) ratio derived from digitized images.
Main Results:
- High-quality retinal images were obtained from 81% of participants.
- Retinal vascular abnormalities were observed in a significant proportion of the cohort.
- Higher mean arteriolar blood pressure (MABP) was significantly associated with increased A/V ratio, focal arteriolar narrowing, AV nicking, and retinopathy (P < 0.0001).
Conclusions:
- Established protocols for retinal vascular assessment using nonmydriatic fundus photography.
- Demonstrated significant associations between retinal microvascular changes and elevated blood pressure.
- Further research is needed to determine if these changes predict future cerebrovascular and cardiovascular events.
Objective:
To develop protocols to photograph and evaluate retinal vascular abnormalities in the Atherosclerosis Risk in Communities (ARIC) Study; to test reproducibility of the grading system; and to explore the relationship of these microvascular changes with blood pressure.
Design:
Population-based, cross-sectional study.
Participants:
Among 4 examination centers, 11,114 participants (48-73 years of age) at their third triennial examination, after excluding persons with diabetes from this analysis.
Methods:
One eye of each participant was photographed by technicians with nonmydriatic fundus cameras. Reading center graders evaluated focal arteriolar narrowing, arteriovenous (AV) nicking, and retinopathy by examining slides on a light box and measured diameters of all vessels in a zone surrounding the optic disc on enhanced digitized images. To gauge generalized narrowing, vessel diameters were combined into central arteriolar and venular equivalents with formulas adjusting for branching, and the ratio of equivalents (A/V ratio) was calculated.
Main Outcome Measures:
Retinal vascular abnormalities, mean arteriolar blood pressure (MABP).
Results:
Among 11,114 participants, photographs were obtained of 99%, with quality sufficient to perform retinal evaluations in 81%. In the 9040 subjects with usable photographs, A/V ratio (lower values indicate generalized arteriolar narrowing) ranged from 0.57 to 1.22 (median = 0.84, interquartile range = 0.10), focal arteriolar narrowing was found in 7%, AV nicking in 6%, and retinopathy in 4%. Because of attrition of subjects and limitation of methods, prevalence of abnormality was likely underestimated. Controlling for gender, race, age, and smoking status, these retinal changes were associated with higher blood pressure. For every 10-mmHg increase in MABP, A/V ratio decreased by 0.02 unit (P < 0.0001), focal arteriolar narrowing had an odds ratio (OR) of 2.00 (95% confidence interval [CI] = 1.87-2.14), AV nicking had an OR of 1.25 (95% CI = 1.16-1.34), and retinopathy had an OR of 1.25 (95% CI = 1.15-1.37). For any degree of generalized narrowing, individuals with focal narrowing had MABP approximately 8 mmHg higher than those without (P < 0.0001). Masked replicate assessment of a sample found the following reproducibility: for A/V ratio, correlation coefficient = 0.79 and median absolute difference = 0.03; for focal arteriolar narrowing, kappa = 0.45; for AV nicking, kappa = 0.61; and for retinopathy, kappa = 0.89.
Conclusion:
Protocols have been developed for nonmydriatic fundus photography and for evaluation of retinal vascular abnormalities. Several microvascular changes were significantly associated with higher blood pressure; follow-up will show whether these are predictive of later cerebrovascular or cardiovascular disease independently of other known risk factors.
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