Retinal associations of diabetes and vascular disease

© 2009 Dr. Swetha JeganathanBackground: Diabetes mellitus and vascular diseases have a significant impact on the eye. Aim: To determine the prevalence, risk factors, and racial/ethnic differences of major eye conditions, particularly retinal conditions, associated with diabetes and vascular diseases. Scope: To date, the majority of studies have examined the association of retinal vascular calibre and diabetes in predominantly white Caucasian populations. Further elucidation of ethnic differences in effects of hyperglycaemia on early microvascular disease is relevant, particularly amongst Asians where diabetes is likely to see the largest increase in prevalence over the next decade. We therefore examined these findings from three Asian population-based studies, the Singapore Malay Eye Study (n=3280), Singapore Prospective Cohort Study and Singapore Cardiovascular Cohort Study 2 (n=3748). Results: The prevalence of diabetic retinopathy in the Singapore Malay Eye Study was 35%, and associated with longer duration of diabetes, poorer glycemic and blood pressure control. More importantly, 9.0% had vision-threatening retinopathy, and retinopathy was found in 6.0% of people without diabetes. Retinal vascular calibre changes were incriminated in diseases such as diabetes and hypertension, independent of traditional cardiovascular risk factors. Wider venular calibre was independently associated with early age-related macular degeneration. We also found a novel association between peripheral artery disease and glaucoma, stronger in persons with diabetes, independent of vascular risk factors, supporting the vascular theory of glaucoma. Implications: Subtle changes in retina, including retinal vascular calibre may be early markers of widespread microvascular changes in diabetes, resulting from chronic hyperglycaemia and other pathogenic processes. These results will have broad implications for understanding the impact of both microvascular and macrovascular complications of diabetes in the Asia Pacific region and targeting relevant therapeutic interventions