Diabetes is one of the leading causes of blindness in adults over 55. Changes in blood sugar may cause vision to fluctuate, causing glasses prescriptions to frequently change. Diabetes can also cause problems to the retina known as diabetic retinopathy. This usually includes bleeding in the retina, and may cause permanent vision loss. Elevated blood pressure along with uncontrolled blood sugar levels combine for even higher risk of diabetic retinal disease. It’s recommended for all diabetics to have a comprehensive eye exam at least once every 12 months. Due to vision changes, eye doctors are sometimes the first to diagnose diabetes.