Diabetes mellitus is the most common endocrine disease in developed countries, with prevalence estimates ranging between 2 to 5% of the world's population. Diabetic retinopathy and diabetic macular edema are common microvascular complications in diabetic patients and may lead to decreasing of visual acuity, eventually to blindness. The Wisconsin Epidemiologic Study found an incidence of macular edema of 20.1% in the younger-onset group and of 14 to 25% in patients with type 2 diabetes mellitus over a period of 10 years.