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Ophthalmology
Volume 106, Issue 12 , 1 December 1999, Pages 2269-2280

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doi:10.1016/S0161-6420(99)90525-0
Copyright © 1999 American Academy of Ophthalmology, Inc. Published by Elsevier Science Inc.

##

Methods for evaluation of retinal microvascular abnormalities associated with hypertension/sclerosis in the atherosclerosis risk in communities study 1, , *1

Larry D. Hubbard MAT1, , Rosemary J. Brothers BS1, William N. King MS1, Limin X. Clegg PhD2, Ronald Klein MD, MPH1, Lawton S. Cooper MD, PhD3, A. Richey Sharrett MD, DrPH3, Matthew D. Davis MD1, Jianwen Cai PhD and Atherosclerosis Risk in Communities Study Group4

1 ARIC Retinal Reading Center, Department of Ophthalmology & Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA
2 National Cancer Institute, National Institutes of Health, Bethesda, Maryland, USA
3 ARIC Project Office, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, Maryland, USA
4 ARIC Coordinating Center, Department of Biostatistics, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA
Received 12 January 1999; accepted 16 August 1999; Manuscript no. 99020. Available online 25 August 2003.

## Abstract

## 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.

Corresponding author. Address correspondence to Larry D. Hubbard, MAT, ARIC Retinal Reading Center, Department of Ophthalmology & Visual Sciences, University of Wisconsin - Madison, 610 North Walnut St, WARF Bldg, Rm 438, , Madison, WI 53705-2397 , USA

*1 Supported by The National Heart, Lung, and Blood Institute of the National Institutes of Health, Contract Numbers NO1-HC-35125, N01-HC-35126, N01-HC-55015, N01-HC-55016, N01-HC-55018, N01-HC-55019, N01-HC-55020, N01-HC-55021, and N01-HC-55022.

1 The authors have no proprietary interest in the equipment and techniques described in this article.

|  | This Document |  |
|  |  | Abstract |  |
|  | External Links |  |
|  | Actions |  |
|  |  | Cited By |  |
|  |  | Save as Citation Alert |  |
|  |  | E-mail Article |  |
|  |  | Export Citation |  |
Ophthalmology Volume 106, Issue 12 , 1 December 1999, Pages 2269-2280

|  |  |  | 21 of 40 |

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