Diabetic retinopathy is caused by the progression of type 1 and type 2 diabetes. Inflammation, changes to blood vessels as a person ages, cholesterol levels, and other factors contribute to the development of this condition in patients with diabetes. Even with good control of blood sugar levels, diabetic retinopathy may still develop if you have been living with diabetes for a long time. It is especially important to visit an eye doctor annually if you have diabetes so any progression can be identified early.