What is diabetes, and how does it affect the eye?

Diabetes is a disease that prevents your body from producing or using insulin effectively, which leads to increased levels of glucose (sugar) in the blood. The elevated glucose levels damage the delicate lining of the blood vessels, causing swelling, bleeding, and poor supply of oxygen and nutrients to vital organs like the heart, kidneys, liver, brain, and eye: a condition known as diabetic retinopathy.