Epidemiology of diabetic retinopathy. Prevalence, progression, vision impairment, and blindness in Germany

The risk of microvascular complications in people with diabetes rises with long-term increases of blood glucose levels. The prevalence of diabetic retinopathy is dependent on disease duration, selection of patients, risk factors (age, HbA(1c) [hemoglobin A(1c)], hypertension), diagnostic criteria, study design, and period of data collection. In primary care, the prevalence of retinopathy in patients with type2 diabetes is about 10% and considerably lower than in secondary and tertiary care with 20-25%. In patients with type1 diabetes there is nearly no difference in the prevalence of retinopathy with 24% in primary care and 27-30% in secondary and tertiary care. Even in people who do not have diabetes, about 10% show transformations of the retina that could be interpreted as mild stages of diabetic retinopathy and do not impair vision. Advanced stages of retinopathy can deteriorate visual acuity, which affects about asixth of all cases of diabetic retinopathy. The prevalence of severe forms of retinopathy that result in blindness has distinctly declined due to optimized diagnosis and treatment of retinopathy and maculopathy.