Case Series: Retrospective Review of Incidental Retinal Emboli Found on Diabetic Retinopathy Screening: Is There a Benefit to Referral for Work-Up and Possible Management?

INTRODUCTION With the rising utilization of diabetic retinopathy photography screening programs across the country, many clinical and socioeconomic questions remain. For the most part, diabetic retinopathy findings have standard follow-up and referral guidelines.1 However, management of other pathology, such as retinal arteriolar emboli, in this patient population is less clear. The association of these lesions with cerebrovascular and cardiovascular morbidity and mortality has been well described in the literature.2,3 Retinal emboli are associated with a higher risk of stroke4 and, as shown by a pooled analysis of two large, population-based studies, predict a modest increase in allcause and stroke-related mortality independent of cardiovascular risk factors.5 Retinal emboli have been identified in 1.3–1.4%6,7 of individuals > 40 years of age. These are plaque-like lesions wedged within retinal arterioles. They are ovalor rhomboid-shaped and have either a reflective or nonreflective appearance.8,9 Reflective emboli are composed of cholesterol crystals, whereas nonreflective types consist of fibrin, platelets, and calcium.10 Cholesterol emboli, also known as Hollenhorst plaques, are the most common, accounting for about 80%.7,11 There are various sources for retinal arteriolar emboli. It is thought that cholesterol emboli ulcerate from atheromatous internal or common carotid plaques, plateletfibrin emboli arise from mural thrombus in the carotid, and calcific emboli originate from cardiac valvular structures.12,13 The relationship between diabetes and retinal emboli is not well characterized. Of the two large studies that have examined retinal emboli— the Beaver Dam Eye Study (BDES)6 and the Blue Mountains Eye Study (BMES)7—only the BDES found that subjects with retinal emboli had a higher prevalence of diabetes than when compared to those patients without retinal emboli. Because retinal arteriolar emboli are associated with a higher risk of stroke and cardiovascular disease, patients found to have retinal emboli sometimes undergo cardiovascular assessment.5 However, the frequency and variation of cardiovascular assessments and surgical or pharmacological interventions after findings of retinal emboli have not been well described. The purpose of this retrospective case series review was to characterize and assess the management of retinal arteriolar emboli in a population of type 2 diabetic patients. QUESTIONS 1. What is the relationship among retinal arteriolar emboli and diabetes, vascular disease, and overall mortality? 2. Should patients with asymptomatic retinal arteriolar emboli detected on diabetic retinopathy screening be referred for further cardiovascular evaluation and management? 3. What is the cost-effectiveness of further imaging studies after the incidental detection of retinal arteriolar emboli?