Diabetic retinopathy is the principal cause of irreversible blindness in patients of working age in the industrialized world (1,2). For some types of retinopathy (e.g., proliferative disease), effective treatment in the form of laser photocoagulation has been available for more than 20 years, but many patients seek help too late when treatment is no longer effective. Macular edema, which is much more common in patients with type 2 diabetes mellitus, may be the presenting sign and therefore may already be established at diagnosis. If vision is significantly reduced, current treatment options are often ineffective. Screening of diabetic persons for early signs of retinopathy, which are treatable, improves the visual prognosis. Medical factors such as good blood glucose control, management of hypertension, and regulation of blood lipid levels are also considered to be of major importance.