Diabetic Retinopathy

What is it?

Our bodies use food as a source of energy. The main source of energy in food is glucose, a form of sugar. As food is digested, it is broken down into glucose molecules which enter the bloodstream and are distributed to cells throughout the body. For glucose to enter cells, however, insulin, a hormone produced by the pancreas, must be present.

Normally, enough insulin is produced to move glucose into cells. In people with diabetes, however, either not enough insulin is produced or cells do not respond properly to the insulin. As a result, glucose remains in the blood and cells are not provided with their main energy source.

High blood sugar levels affect many tissues in the body including the skin, heart, kidneys, nervous system, feet, teeth, gums and eyes. Diabetic retinopathy refers to damage to the blood vessels of the retina caused by diabetes. These blood vessels bring oxygen and nutrients to the retina. When the blood vessels are become damaged, they weaken and sometimes break, leaking fluid into the retina and causing the retina may to swell. As new blood vessels grow on the retina, blurred vision or temporary blindness can result. Scare tissue can form and cause blindness where old blood vessles were attached to the retina.

Photograph of the retina showing abnormal new blood vessels and scar tissue in an advanced stage of retinal neuropathy.
Images modified from National Institute of Diabetes and Digestive and Kidney Diseases and National Eye Institute, National Institutes of Health


Diabetic neuropathy may cause:

  • Spots floating in the visual field
  • Vision loss
  • Poor night vision
  • Blurred vision

Image modified from National Eye Institute, National Institutes of Health

Risk Factors



Did you know?

According to the National Eye Institute, diabetic retinopathy is the leading cause of blindness in American adults. Diabetic retinopathy accounts for 12% of all new cases of blindness in the US (reference: Duh, E.J. and Aiello, L.P. Basic Pathobiology of the eye and its complications, in Porte, Jr. et al., editors, Ellenberg & Rifkin's Diabetes Mellitus, New York: McGraw-Hill, 2002.)