Prevalence of asymptomatic retinal emboli in an Australian urban community

Because no population-based estimates are available for asymptomatic retinal emboli, we aimed to assess prevalence and associations of this sign in a defined older Australian urban population.

A total of 3654 persons aged 49 years or older, representing 82% of residents in an urban area west of Sydney, underwent a detailed eye examination that included medical history, stereo retinal photography, and fasting blood tests including lipids. Retinal emboli were diagnosed clinically and from photographic grading and classified as cholesterol, platelet-fibrin, or calcific in type.

Asymptomatic retinal emboli were found in 51 participants (1.4%; 95% confidence interval [CI], 1.0% to 1.8%). The prevalence was 0.8% in persons aged < 60 years, 1.4% for those aged 60 to 69 years, 2.1% for those aged 70 to 79 years, and 1.5% for those aged 80 years or older. Men had a significantly higher prevalence (2.2%) of retinal emboli than women (0.8%, P < .001) after adjustment for age (odds ratio [OR], 2.7; 95% CI, 1.5 to 4.8). Forty-one emboli (80%) were cholesterol type, 7 (14%) were platelet-fibrin, and 3 (6%) were calcific. Significant associations were found after age-sex adjustment, with hypertension (OR, 2.2; 95% CI, 1.2 to 3.8), a combined history of vascular disease (OR, 2.4; 95% CI, 1.3 to 4.4), past vascular surgery (OR, 3.5; 95% CI, 1.4 to 8.5), and current (OR, 2.2; 95% CI, 1.1 to 4.2) or any (OR, 2.6; 95% CI, 1.2 to 4.3), smoking history. These associations persisted after multivariate analysis. There were no significant associations with diabetes, obesity, or fasting blood test findings.

This study provides accurate prevalence rates for asymptomatic retinal emboli in the elderly and confirms associations with hypertension, smoking, and vascular disease.