People with diabetes can develop diabetic retinopathy. Initially, diabetic retinopathy may present with no symptoms but, if left untreated, will eventually, lead to blindness. Diabetic retinopathy occurs when blood sugar levels become continually elevated, causing damage to blood vessels in the retina. These damaged blood vessels can leak or swell, stopping oxygenated blood from passing throughout the retina. As a result, the retina becomes damaged and then attempts to grow new blood vessels. Unfortunately, these new blood vessels don’t develop properly and can also leak.