Diabetic retinopathy is a complication of diabetes mellitus. Diabetes mellitus is a condition in which the body is unable to use and store glucose (sugar) properly. Over time, elevated glucose levels in the bloodstream result in damage to the small blood vessels in the body, particularly in various organs such as the eyes, heart, and kidneys.

Diabetes can affect the eyes by causing deterioration of retinal blood vessels which may result in diabetic macular edema or neovascularization.

• Diabetic macular edema (DME) is caused by the formation of microaneurysms that leak fluid into the center of the retina.
• Neovascularization is caused by abnormal blood vessels that grow on the surface of the retina or iris, which can cause bleeding, scarring, and retinal detachment.

Both conditions can lead to loss of central vision and possibly peripheral vision.