Diabetic retinopathy is caused by damage from diabetes to blood vessels of the retina. The retina is the layer of tissue at the back of the inner eye. It changes light and images that enter the eye into nerve signals, which are sent to the brain.
Diabetic retinopathy is a main cause of blindness in Americans 20 to 74 years old. People with type 1 or type 2 diabetes are at risk of this condition.
Many people with early diabetic retinopathy have no symptoms before bleeding occurs in the eye. This is why everyone with diabetes should have regular eye exams.
Signs and tests
Your eye doctor (ophthalmologist) will examine your eyes. You may first be asked to read an eye chart. Then you will receive eyedrops to widen the pupils of your eyes. Tests you may have involve:
Measuring the fluid pressure inside your eyes (tonometry)
Checking the structures inside your eyes (slit lamp exam)
Checking and photographing your retinas (fluorescein angiography)
If you have the early stage of diabetic retinopathy (nonproliferative), the eye doctor may see:
Blood vessels in the eye that are larger in certain spots (called microaneurysms)
Blood vessels that are blocked
Small amounts of bleeding (retinal hemorrhages) and fluid leaking into the retina
If you have advanced retinopathy (proliferative), the eye doctor may see:
New blood vessels starting to grow in the eye that are weak and can bleed
Small scars forming on the retina and in other parts of the eye (the vitreous)
Persons with early diabetic retinopathy may not need treatment. But they should be closely followed by an eye doctor who is trained to treat diabetic eye diseases.
Once your eye doctor notices new blood vessels growing in your retina (neovascularization) or you develop macular edema, treatment is usually needed.
Eye surgery is the main treatment for diabetic retinopathy.
Laser eye surgery creates small burns in the retina where there are abnormal blood vessels. This process is called photocoagulation. It is used to keep vessels from leaking or to shrink abnormal vessels.
Surgery called vitrectomy is used when there is bleeding (hemorrhage) into the eye. It may also be used to repair retinal detachment.
Medicines that are injected into the eyeball may help prevent abnormal blood vessels from growing.
Follow your eye doctor's advice on how to protect your vision. Have eye exams as often as recommended.
Managing your diabetes may help slow diabetic retinopathy and other eye problems. Control your blood sugar (glucose) level by:
Eating healthy foods
Getting regular exercise
Checking it as often as instructed by your diabetes health care provider and keeping a record of your numbers so you know the things that affect your level
Taking medicine or insulin as instructed
Treatments can reduce vision loss. They do not cure diabetic retinopathy or reverse the changes that have already occurred.
Diabetic eye disease can lead to reduced vision and blindness.
Calling your health care provider
Call for an appointment with an eye doctor (ophthalmologist) if you have diabetes and you have not seen an ophthalmologist in the past year.
Call your doctor if any of the following symptoms are new or are becoming worse:
You cannot see well in dim light.
You have blind spots.
You have double vision (you see two things when there is only one).
Your vision is hazy or blurry and you cannot focus.
You have pain in one of your eyes.
You are having headaches.
You see spots floating in your eyes.
You cannot see things on the side of your field of vision.
You see shadows.
Tight control of blood sugar, blood pressure, and cholesterol is very important for preventing diabetic retinopathy.
Do not smoke. If you need help quitting, ask your doctor or nurse.
American Diabetes Association. Standards of medical care in diabetes -- 2013. Diabetes Care. 2013;36 Suppl 1:S11-S66.
Brownlee M, Aiello LP, Cooper ME, et al. Complications of diabetes mellitus. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM. Williams Textbook of Endocrinology. 12th ed. Philadelphia, Pa.: Elsevier Saunders; 2011: chap 33.
Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Bethanne Black, and the A.D.A.M. Editorial team.