Diabetic retinopathy is the most common complication of diabetes mellitus (DM). This condition is one of the largest causes of vision loss worldwide and is the leading cause of impaired vision in patients ages 25 to 74. In patients with diabetes mellitus, the body does not use and store sugar appropriately. High blood sugar levels cause damage to blood vessels in the retina, leading to bleeding, swelling, leakage, and abnormal new blood vessel growth. This retinal damage is referred to as diabetic retinopathy.