Diabetes causes cataracts, glaucoma, refractive errors, optic nerve inflammation, eye muscle paralysis as well as various damage to the retina. Diabetic retinopathy is the most common cause of blindness due to diabetes and it progresses very insidiously. Therefore, diabetic patients should have an eye examination periodically.

The risk of developing retinopathy in someone with diabetes for 15 years is 80%. In diabetes mellitus in children, retinopathy begins at a younger age.