Risk factors and significance of finding asymptomatic retinal emboli

To assess the prevalence rates for asymptomatic retinal emboli among both younger and older individuals, with single and multiple potential risk factors, in order to alert clinicians to the probability of finding retinal emboli in patients with varying characteristics.

In all, 3654 people aged 49-97 attending the Blue Mountains Eye Study had a detailed eye examination which included retinal photographs of the central and peripheral retinal fields. Retinal emboli were identified during masked photographic grading and definite cases were adjudicated.

Retinal emboli were found in 51 subjects (1.4% of the population); these included 1.1% of people aged 49-69 years (middle-aged subjects) and 2.0% of people aged more than 70 years (older subjects). Risk factors identified were male sex, increasing age, hypertension, current smoking, history of any vascular event (angina, myocardial infarct, stroke) or history of vascular surgery. Among middle-aged subjects, current smoking and history of hypertension or a vascular event were significantly associated with emboli (odds ratios (OR) 2.3-3.1), while in older subjects, history of vascular surgery was related (OR 4.7). The highest prevalence of emboli (5.5%) was found in people who reported a history of hypertension and also smoked (OR 6.0). Among hypertensive men who smoked, emboli were present in 7.6%.

This study indicates that although asymptomatic retinal emboli are relatively infrequent in the general older population, these lesions are surprisingly common in people (particularly men) with multiple risk factors. Ophthalmologists could routinely screen for emboli and consider alerting the patients' general practitioners to review vascular risk factors.