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Diabetic Retinopathy

Topic Overview

The eye

What is diabetic retinopathy?

Retinopathy is a disease of the retina. The retina is the nerve layer that lines the back of your eye. It is the part of your eye that "takes pictures" and sends the images to your brain. Many people with diabetes get retinopathy. This kind of retinopathy is called diabetic retinopathy (retinal disease caused by diabetes).

Diabetic retinopathy can lead to poor vision and even blindness. Most of the time, it gets worse over many years. At first, the blood vessels in the eye get weak. This can lead to blood and other liquid leaking into the retina from the blood vessels. This is called nonproliferative retinopathy. And this is the most common retinopathy. If the fluid leaks into the center of your eye, you may have blurry vision. Most people with nonproliferative retinopathy have no symptoms.

If blood sugar levels stay high, diabetic retinopathy will keep getting worse. New blood vessels grow on the retina. This may sound good, but these new blood vessels are weak. They can break open very easily, even while you are sleeping. If they break open, blood can leak into the middle part of your eye in front of the retina and change your vision. This bleeding can also cause scar tissue to form, which can pull on the retina and cause the retina to move away from the wall of the eye (retinal detachment). This is called proliferative retinopathy. Sometimes people don't have symptoms until it is too late to treat them. This is why having eye exams regularly is so important.

Retinopathy can also cause swelling of the macula of the eye. This is called macular edema. The macula is the middle of the retina, which lets you see details. When it swells, it can make your vision much worse. It can even cause legal blindness.

What causes diabetic retinopathy?

If you are not able to keep your blood sugar levels in a target range, it can cause damage to your blood vessels. Diabetic retinopathy happens when high blood sugar damages the tiny blood vessels of the retina.

When you have diabetic retinopathy, high blood pressure can make it worse. High blood pressure can cause more damage to the weakened vessels in your eye, leading to more leaking of fluid or blood and clouding more of your vision.

What are the symptoms?

Most of the time, there are no symptoms of diabetic retinopathy until it starts to change your vision. When this happens, diabetic retinopathy is already severe. Having your eyes checked regularly can find diabetic retinopathy early enough to treat it and help prevent vision loss.

If you notice problems with your vision, call an eye doctor (ophthalmologist) right away. Changes in vision can be a sign of severe damage to your eye. These changes can include floaters, pain in the eye, blurry vision, or new vision loss.

How is diabetic retinopathy diagnosed?

An eye exam by an eye specialist (ophthalmologist or optometrist) is the only way to detect diabetic retinopathy. Having a dilated eye exam regularly can help find retinopathy before it changes your vision. On your own, you may not notice symptoms until the disease becomes severe.

Can diabetic retinopathy be prevented?

You can lower your chance of damaging small blood vessels in the eye by keeping your blood sugar levels and blood pressure levels within a target range. If you smoke, quit. All of this reduces the risk of damage to the retina. It can also help slow down how quickly your retinopathy gets worse and can prevent future vision loss.

If you have a dilated eye exam regularly, you and your doctor can find diabetic retinopathy before it has a chance to get worse. For most people, this will mean an eye exam every year. Finding retinopathy early gives you a better chance of avoiding vision loss and blindness.

How is it treated?

Surgery, laser treatment, or medicine may help slow the vision loss caused by diabetic retinopathy. You may need to be treated more than once as the disease gets worse.

Frequently Asked Questions

Learning about diabetic retinopathy:

Being diagnosed:

Getting treatment:

Ongoing concerns:

Living with diabetic retinopathy:

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Cause

Diabetes damages small blood vessels throughout the body, leading to reduced blood flow. When these changes affect the tiny blood vessels in the eyes, diabetic retinopathy may occur.

In the early stage of diabetic retinopathy, tiny blood vessels in the eye weaken and develop small bulges that may burst and leak into the retina. Later, new fragile blood vessels grow on the surface of the retina. These blood vessels may break and bleed into the eye, clouding vision and causing scar tissue to form.

The scar tissue may pull on the retina, leading to retinal detachment. Retinal detachment occurs when the retina separates from the wall of the eye. This can lead to vision loss.

Symptoms

You may have diabetic retinopathy for a long time without noticing any symptoms. Typically, retinopathy does not cause noticeable symptoms until significant damage has occurred and complications have developed.

Symptoms of diabetic retinopathy and its complications may include:

  • Blurred, double, or distorted vision or difficulty reading.
  • Floaters or spots in your vision.
  • Partial or total loss of vision or a shadow or veil across your field of vision.
  • Pain, pressure, or constant redness of the eye.

What Happens

Diabetic retinopathy begins as a mild disease. During the early stage of the disease, the small blood vessels in the retina become weaker and develop small bulges called microaneurysms. These microaneurysms are the earliest signs of retinopathy and may appear a few years after the onset of diabetes. They may also burst and cause tiny blood spots (hemorrhages) on the retina. But they do not usually cause symptoms or affect vision. This is called nonproliferative retinopathy. At this stage, treatment is not required.

As retinopathy progresses, fluid and protein leak from the damaged blood vessels and cause the retina to swell. This may cause mild to severe vision loss, depending on which parts of the retina are affected. If the center of the retina (macula) is affected, vision loss can be severe. Swelling and distortion of the macula (macular edema), which results from a buildup of fluid, is the most common complication of retinopathy. Macular edema treatment usually works to stop and sometimes reverse your loss of vision.

In some people, retinopathy gets worse over the course of several years and progresses to proliferative retinopathy. In these cases, reduced blood flow to the retina stimulates the growth (proliferation) of fragile new blood vessels on the surface of the retina. As the new blood vessels multiply, one or more complications may develop and damage the person's vision. These complications can include:

  • The formation of scar tissue that pulls on the retina, which may lead to retinal detachment.
  • Bleeding inside the eye (preretinal or vitreous hemorrhage).
  • The growth of new blood vessels on the surface of the iris (rubeosis iridis), which eventually leads to a form of severe glaucoma called neovascular glaucoma.

Any of these later complications may cause severe, permanent vision loss.

How Does Diabetes Cause Blindness?

What Increases Your Risk

Your risk for diabetic retinopathy depends largely on two things: how long you have had diabetes and whether or not you have kept good control of your blood sugar.

You can control some risk factors, which are things that may increase your risk for diabetic retinopathy and its complications. Risk factors that you can control include:

  • Pregnancy. Women who have diabetes are at increased risk of developing retinopathy during pregnancy. In women who already have retinopathy when they become pregnant, the condition can become much worse during pregnancy. If you get pregnant, you will need to have an eye exam sometime during the first 3 months. You'll also need close follow-up during your pregnancy and for 1 year after you have your baby.1
  • Consistently high blood sugar. High blood sugar levels increase your risk of retinopathy. Keeping your blood sugar levels in a target range can reduce your risk for diabetic retinopathy and can slow the progression of the disease if it has already started.
  • High blood pressure. In general, people with diabetes who also have high blood pressure are more likely to develop complications that affect the blood vessels in the body, including those in the eyes.
  • Delayed diagnosis and treatment. Getting a dilated eye exam will not prevent retinopathy. But it may reduce your risk of severe vision loss from complications of retinopathy. By detecting it early, you can get treatment that can prevent vision loss and delay the progression of the disease.
  • Smoking. Although smoking has not been proved to increase the risk of retinopathy, smoking may make many of the other health problems faced by people with diabetes worse, including disease of the small blood vessels.

If you have type 2 diabetes and use the medicine rosiglitazone (Avandia, Avandamet, Avandaryl) to treat your diabetes, you may have a higher risk for problems with the center of the retina (the macula). The U.S. Food and Drug Administration (FDA) and the makers of the drug have warned that taking this medicine could cause swelling in the macula, which is called macular edema.

When To Call a Doctor

Call your doctor immediately if you have diabetes and notice:

  • Floaters in your field of vision. Floaters often appear as dark specks, globs, strings, or dots. A sudden shower of floaters may be a sign of a retinal detachment, which is a serious complication of diabetic retinopathy.
  • A new visual defect, shadow, or curtain across part of your vision. This is another sign of retinal detachment.
  • Eye pain or a feeling of pressure in your eye.
  • New or sudden vision loss. The sudden onset of partial or complete vision loss is a symptom of many disorders that can occur within or outside the eye, including retinal detachment or bleeding within the eye. Sudden vision loss is always a medical emergency.

Watchful waiting

Watchful waiting is not an option if you have diabetes and notice changes in your vision.

If you have type 2 diabetes, even if you do not have any symptoms of eye disease, you still need to have your eyes and vision checked regularly by an eye specialist (ophthalmologist or optometrist). If you wait until you have symptoms, it is more likely that complications and severe damage to the retina will have already developed. These may be harder to treat and may result in permanent vision loss.

If you have type 1 diabetes, are age 10 or older, and were diagnosed 5 or more years ago, you should have your eyes checked even if you don't have symptoms. If you wait until you have symptoms, it is more likely that complications and severe damage to the retina will have happened. These may be harder to treat. And the damage may be permanent.

Watchful waiting is not an option if you already have diabetic retinopathy but do not have symptoms or vision loss. You will need to return to your ophthalmologist for frequent evaluations (every few months in some cases) so that your doctor can closely monitor changes in your eyes. There is no cure for the disease. But treatment can slow its progression. Your ophthalmologist can tell you how often you need to be evaluated.

Who to see

People who have diabetes need to see a doctor who specializes in eye care for their eye evaluations.

If you have diabetic retinopathy and need laser treatment or surgery, you need to consult an ophthalmologist who specializes in treating the retina and has special training in the care of eye disease caused by diabetes.

To prepare for your appointment, see the topic Making the Most of Your Appointment.

Exams and Tests

Diabetic retinopathy can be detected during a dilated eye exam by an ophthalmologist or optometrist. An exam by your primary doctor, during which your eyes are not dilated, is not an adequate substitute for a full exam done by an ophthalmologist. Eye exams for people with diabetes can include:

  • Visual acuity testing. Visual acuity testing measures the eye's ability to focus and to see details at near and far distances. It can help detect vision loss and other problems.
  • Ophthalmoscopy and slit lamp exam. These tests allow your doctor to see the back of the eye and other structures within the eye. They may be used to detect clouding of the lens (cataract), changes in the retina, and other problems.
  • Gonioscopy. Gonioscopy is used to find out whether the area where fluid drains out of your eye (called the drainage angle) is open or closed. This test is done if your doctor thinks you may have glaucoma, a group of eye diseases that can cause blindness by damaging the optic nerve.
  • Tonometry. This test measures the pressure inside the eye, which is called intraocular pressure (IOP). It is used to help detect glaucoma. Diabetes can increase your risk of glaucoma.

Your doctor may also do a test called an optical coherence tomography (OCT) to check for fluid in your retina. Sometimes a fluorescein angiogram is done to check for and locate leaking blood vessels in the retina, especially if you have symptoms, such as blurred or distorted vision, that suggest damage to or swelling of the retina.

Fundus photography can track changes in the eye over time in people who have diabetic retinopathy and especially in those who have been treated for it. Fundus photography produces accurate pictures of the back of the eye (the fundus). An eye doctor can compare photographs taken at different times to watch the progression of the disease and find out how well treatment is working. But the photos do not take the place of a full eye exam.

Early detection

Early detection and treatment of diabetic retinopathy can help prevent vision loss. For people in whom diabetic retinopathy has not been diagnosed, the American Diabetes Association recommends that screening be done based on the following guidelines:1

  • People with type 1 diabetes who are age 10 and older should have a dilated eye exam within 5 years after diabetes is diagnosed and then every year.
  • People with type 2 diabetes should have an exam as soon as diabetes is diagnosed and then every year.
  • If your eye exam results are normal, your doctor may consider follow-up exams every 2 to 3 years. But if you are diagnosed with retinopathy, you may need frequent eye exams.
  • Women who have type 1 or type 2 diabetes and who are planning to become pregnant should have an exam before becoming pregnant, if possible, and then once during the first 3 months (first trimester) of pregnancy. The eye doctor can decide whether you need further screening for retinopathy during pregnancy based on the results of the first-trimester exam.

Note: Pregnant women who develop gestational diabetes are not at risk for diabetic retinopathy and do not need to be screened for it. (But women who develop gestational diabetes during pregnancy have a greater chance of developing type 2 diabetes later in life, which can put them at increased risk for retinopathy and other eye problems.)

People who have diabetes are also at increased risk for other eye diseases, including glaucoma and cataracts. Regular dilated eye exams can help detect these diseases early and prevent or delay vision loss.

Treatment Overview

There is no cure for diabetic retinopathy. But laser treatment (photocoagulation) is usually very effective at preventing vision loss if it is done before the retina has been severely damaged. Surgical removal of the vitreous gel (vitrectomy) may also help improve vision if the retina has not been severely damaged. Sometimes injections of an anti-VEGF (vascular endothelial growth factor) medicine or an anti-inflammatory medicine help to shrink new blood vessels in proliferative diabetic retinopathy. Because symptoms may not develop until the disease becomes severe, early detection through regular screening is important. The earlier retinopathy is detected, the easier it is to treat and the more likely vision will be preserved.

You may not need treatment for diabetic retinopathy unless it has affected the center (macula) of the retina or, in rare cases, if your side (peripheral) vision has been severely damaged. But you do need to have your vision checked regularly.

If the macula has been damaged by macular edema, you may need laser treatment. For more severe retinopathy, you may need either laser treatment or vitrectomy. These procedures can help prevent, stabilize, or slow vision loss when they are done before the retina has been severely damaged. Newer treatment includes medicines like anti-VEGF medicine or steroids that are injected into the eye.

Surgical removal of the vitreous gel (vitrectomy) is done when there is bleeding (vitreous hemorrhage) or retinal detachment, which are rare in people with early-stage retinopathy. Vitrectomy is also done when severe scar tissue has formed.

Treatment for diabetic retinopathy is often very effective in preventing, delaying, or reducing vision loss. But it is not a cure for the disease. People who have been treated for diabetic retinopathy need to be monitored frequently by an eye doctor to check for new changes in their eyes. Many people with diabetic retinopathy need to be treated more than once as the condition gets worse.

Also, controlling your blood sugar levels is always important. This is true even if you have been treated for diabetic retinopathy and your eyes are better. In fact, good blood sugar control is especially important in this case so that you can help keep your retinopathy from getting worse.

Ideally, laser treatment should be done early in the course of the disease to prevent serious vision loss rather than to try to treat serious vision loss after it has already developed.

People with diabetes who have any signs of retinopathy need to be examined as soon as possible by an ophthalmologist.

Prevention

There are steps you can take to reduce your chance of vision loss from diabetic retinopathy and its complications:

  • Control your blood sugar levels. Keep blood sugar levels in a target range by eating a healthful diet, frequently monitoring your blood sugar levels, getting regular physical exercise, and taking insulin or medicines for type 2 diabetes if prescribed.
  • Control your blood pressure. Retinopathy is more likely to progress to the severe form and macular edema is more likely to occur in people who have high blood pressure. It is not clear whether treating high blood pressure can directly affect long-term vision. But in general, keeping blood pressure levels in a target range can reduce the risk of many different complications of diabetes. For more information about how to control your blood pressure, see the topic High Blood Pressure.
  • Have your eyes examined by an eye specialist (ophthalmologist or optometrist) every year. Screening for diabetic retinopathy and other eye problems will not prevent diabetic eye disease. But it can help you avoid vision loss by allowing for early detection and treatment.
  • See an ophthalmologist if you have changes in your vision. Changes in vision—such as floaters, pain or pressure in the eye, blurry or double vision, or new vision loss—may be symptoms of serious damage to your retina. In most cases, the sooner the problem can be treated, the more effective the treatment will be.

The risk for severe retinopathy and vision loss may be even less if you:

  • Don't smoke. Although smoking has not been proved to increase the risk of retinopathy, smoking may aggravate many of the other health problems faced by people with diabetes, including disease of the small blood vessels.
  • Avoid hazardous activities. Certain physical activities, like weight lifting or some contact sports, may trigger bleeding in the eye through impact or increased pressure. Avoiding these activities when you have diabetic retinopathy can help reduce the risk of damage to your vision.
  • Get adequate exercise. Exercise helps keep blood sugar levels in a target range, which can reduce the risk of vision damage from diabetic retinopathy. Talk to your doctor about what kinds of exercise are safe for you.

Surgery

Surgical treatment for diabetic retinopathy is removal of the vitreous gel (vitrectomy). Vitrectomy does not cure the disease. But it may improve vision in people who have developed bleeding into the vitreous gel (vitreous hemorrhage), retinal detachment, or severe scar tissue formation.

Unfortunately, by the time some people are diagnosed with retinopathy (especially late-stage retinopathy), it is often too late for vitrectomy to provide much benefit. Even with treatment, vision may continue to decline.

Early detection of retinopathy through dilated eye exams can help you decide to have surgery when it is most effective.

What to think about

After a person has had most of the vitreous gel removed by vitrectomy, surgery to remove scar tissue or to repair a new retinal detachment may be needed.

Vitrectomy may require an overnight hospital stay. But it is sometimes done as outpatient surgery. Your eye doctor will determine if the surgery can be done with local or general anesthesia.

Other Treatment

Laser treatment (photocoagulation) can be an effective treatment for diabetic retinopathy. But it does not cure the disease. It can prevent, delay, and sometimes reverse vision loss. Without either laser treatment or surgery, vision loss caused by diabetic retinopathy and its complications may get worse until blindness occurs. So early treatment is vital to slowing vision loss, which can happen quickly.

When diabetic retinopathy causes bleeding (hemorrhage) into the vitreous gel, extensive scar tissue formation, or retinal detachment, surgical removal of the vitreous gel (vitrectomy) may be needed before laser treatment is considered.

Unfortunately, by the time some people are diagnosed with diabetic retinopathy, it is often too late for treatment to provide much benefit. Even with treatment, vision will continue to decline.

Early detection of retinopathy through dilated eye exams can provide the opportunity to have laser treatment when it is most effective.

Other treatment choices

Laser photocoagulation uses the heat from a laser to seal or destroy abnormal, leaking blood vessels in the retina. It can cause the abnormal, weak blood vessels to shrink.

Some anti-VEGF (vascular endothelial growth factor) medicines, such as ranibizumab (Lucentis), can help treat macular edema from diabetic retinopathy.

What to think about

Pan-retinal laser treatment is used to treat several spots on the retina during one or, most often, two sessions. It reduces the risk of serious bleeding and the progression of severe proliferative retinopathy.

Laser photocoagulation can result in some loss of vision, because it destroys some of the nerve cells in the retina and can cause the abnormal blood vessels to go away. With pan-retinal photocoagulation, this most often affects the outside (peripheral) vision, because the laser is directed at that area. Your vision may be worse right after treatment. But vision loss caused by laser treatment is mild compared with the vision loss that may be caused by untreated retinopathy.

Other Places To Get Help

Organizations

American Diabetes Association (ADA)
1701 North Beauregard Street
Alexandria, VA  22311
Phone: 1-800-DIABETES (1-800-342-2383)
Email: AskADA@diabetes.org
Web Address: www.diabetes.org
 

The American Diabetes Association (ADA) is a national organization for health professionals and consumers. Almost every state has a local office. ADA sets the standards for the care of people with diabetes. Its focus is on research for the prevention and treatment of all types of diabetes. ADA provides patient and professional education mainly through its publications, which include the monthly magazine Diabetes Forecast, books, brochures, cookbooks and meal planning guides, and pamphlets. ADA also provides information for parents about caring for a child with diabetes.


EyeSmart
Web Address: www.geteyesmart.org

National Library Service for the Blind and Physically Handicapped (NLS), Library of Congress
1291 Taylor Street NW
Washington, DC  20011
Phone: 1-888-NLS-READ (1-888-657-7323)
(202) 707-5100
Fax: (202) 707-0712
TDD: (202) 707-0744
Email: nls@loc.gov
Web Address: www.loc.gov/nls/index.html
 

The National Library Service has established a national network of cooperating libraries to provide a free library program of braille and audio materials. Materials, including some magazines, in braille, large print, or cassette can be borrowed postage-free by people who are eligible for the service.


References

Citations

  1. American Diabetes Association (2013). Standards of medical care in diabetes—2013. Diabetes Care, 36(Suppl 1): S11–S66.

Other Works Consulted

  • American Diabetes Association (2013). Standards of medical care in diabetes—2013. Diabetes Care, 36(Suppl 1): S11–S66.
  • Brownlee M, et al. (2011). Complications of diabetes mellitus. In S Melmed et al., eds., Williams Textbook of Endocrinology, 12th ed., pp. 1462–1551. Philadelphia: Saunders.
  • Cavallerano JD, Stanton RM (2010). MIcrovascular complications. In RS Beaser, ed., Joslin's Diabetes Deskbook: A Guide for Primary Care Providers, 2nd ed., pp. 445–473. Boston: Joslin Diabetes Center.
  • Dagogo-Jack S (2010). Complications of diabetes mellitus. In EG Nabel, ed., ACP Medicine, section 9, chap. 3. Hamilton, ON: BC Decker.
  • Fletcher EC, et al. (2011). Retina. In P Riordan-Eva, JP Whitcher, eds., Vaughan and Asbury's General Ophthalmology, 18th ed., pp. 190–221. New York: McGraw-Hill.
  • Gebel E (2010). Aids for insulin users. Diabetes Forecast, 63(1). Available online: http://forecast.diabetes.org/magazine/features/aids-insulin-users.
  • Hammes HP, et al. (2010). Diabetic retinopathy: Targeting vasoregression. Diabetes, 60(1): 9–16. Available online: http://diabetes.diabetesjournals.org/content/60/1/9.full.
  • Massin P, et al. (2010). Safety and efficacy of ranibizumab in diabetic macular edema (RESOLVE study*). Diabetes Care, 33(11): 2399–2405. Available online: http://care.diabetesjournals.org/content/33/11/2399.full.pdf.
  • Mohamed QA, et al. (2011). Diabetic retinopathy (treatment), search date June 2010. BMJ Clinical Evidence. Available online: http://www.clinicalevidence.com.
  • Nicholson BP, Schachat AP (2010). A review of clinical trials of anti-VEGF agents for diabetic retinopathy. Graefe's Archive of Clinical and Experimental Ophthalmology, 248(7): 915–930.

Credits

By Healthwise Staff
Adam Husney, MD - Family Medicine
Carol L. Karp, MD - Ophthalmology
Last Revised February 27, 2013

Last Revised: February 27, 2013

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