Diabetic retinopathy is caused by damage 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 that are sent to the brain.
There are two types, or stages of diabetic retinopathy:
Nonproliferative develops first
Proliferative is the more advanced and severe form of the disease
Diabetic retinopathy is the leading cause of blindness in working-age Americans. People with type 1 diabetes and type 2 diabetes are at risk for this condition.
Having more severe diabetes for a longer period of time increases the chance of getting retinopathy. Retinopathy is also more likely to occur earlier and be more severe if your diabetes has been poorly controlled.
Almost everyone who has had diabetes for more than 30 years will show signs of diabetic retinopathy.
Most often, diabetic retinopathy has no symptoms until the damage to your eyes is severe.
Many people with early diabetic retinopathy have no symptoms before major bleeding occurs in the eye. This is why everyone with diabetes should have regular eye exams.
Signs and tests
The health care provider can diagnose diabetic retinopathy by dilating your pupils with eye drops and then carefully examining the retina. A retinal photography or fluorescein angiography test may also be used.
If you have nonproliferative diabetic retinopathy, your health care provider 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 proliferative retinopathy, your health care provider may see:
New blood vessels starting to grow in the eye that are fragile and can bleed
Small scars developing on the retina and in other parts of the eye (the vitreous)
To prevent diabetic retinopathy:
Keep tight control of your blood sugar (glucose), blood pressure, and cholesterol levels
People with the earlier form (nonproliferative) of diabetic retinopathy may not need treatment. However, they should be closely followed by an eye doctor who is trained to treat diabetic retinopathy.
Treatment usually does not reverse damage that has already occurred. However, it can help keep the disease from getting worse. Once your eye doctor notices new blood vessels growing in your retina (neovascularization) or you develop macular edema, treatment is usually needed.
Several procedures or surgeries are 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 get rid of abnormal, fragile vessels.
Focal laser photocoagulation is used to treat macular edema.
Scatter laser treatment or panretinal photocoagulation treats a large area of your retina. Often two or more sessions are needed.
A surgical procedure called vitrectomy is used when there is bleeding (hemorrhage) into the eye. It may also be used to repair retinal detachment.
Drugs that prevent abnormal blood vessels from growing, and corticosteroids injected into the eyeball are being investigated as new treatments for diabetic retinopathy.
If you cannot see well:
Make sure your home is safe so you do not fall
Organize your home so that you can easily find what you need
Get help to make sure you are taking your medicines correctly
Glaucoma -- increased pressure in the eye that can lead to blindness
Macular edema -- if fluid leaks into the area of the retina that provides sharp vision straight in front of you, your vision becomes more blurry
Retinal detachment -- scarring may cause part of the retina to pull away from the back of your eyeball
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.
You may not know there is any damage to your eyes until the problem is very bad. Your doctor can catch problems early if you get regular exams. You will need to see an eye doctor who is trained to treat diabetic retinopathy.
Begin having eye examinations as follows by an eye doctor skilled in the treatment of diabetic retinopathy:
Children older than 10 years who have had diabetes for 3 - 5 years or more
Adults and adolescents with type 2 diabetes soon after diagnosis
Adolescents and adults with type 1 diabetes within 5 years of diagnosis
After the first exam, most patients should have a yearly eye exam.
If you are beginning a new exercise program or are planning to get pregnant, have your eyes examined. Avoid resistance or high-impact exercises, which can strain already weakened blood vessels in the eyes.
If you are at low risk, you may need follow-up exams only every 2 - 3 years. The eye exam should include dilation to check for signs of retinal disease (retinopathy).
American Diabetes Association. Standards of medical care in diabetes--2011. Diabetes Care. 2011 Jan;34 Suppl 1:S11-61.
O'Doherty M, Dooley I, Hickey-Dwyer M. Interventions for diabetic macular oedema: a systematic review of the literature. Br J Opthalmol. 2008;92:1581-1590.
Diabetic Retinopathy Clinical Research Network (DRCR.net), Beck RW, Edwards AR, Aiello LP, Bressler NM, Ferris F, Glassman AR, et al. Three-year follow-up of a randomized trial comparing focal/grid photocoagulation and intravitreal triamcinolone for diabetic macular edema. Arch Ophthalmol. 2009;127:245-251.
A.D.A.M. Editorial Team: David Zieve, MD, MHA, and David R. Eltz. Previously reviewed by Ari S. Eckman, MD, Chief, Divisiopn of Endocrinology, Diabetes and Metabolism, Trinitas Regional Medical Center, Elizabeth, NJ. Review provided by VeriMed Healthcare Network (6/28/2011).