Diabetic Retinopathy: An Overview
Diabetic retinopathy is a complication of
diabetes and a leading cause of blindness. Diabetic retinopathy occurs when diabetes damages the tiny blood vessels inside the retina, the light-sensitive tissue at the back of the eye. A healthy retina is necessary for good vision.
If you have diabetic retinopathy, at first, you may notice no changes to your vision. But over time, diabetic retinopathy can get worse and cause vision loss. Diabetic retinopathy usually affects both eyes.
Stages of Diabetic Retinopathy
Diabetic retinopathy has four stages:
- Mild nonproliferative retinopathy. At this earliest stage of diabetic retinopathy, microaneurysms occur. These are small areas of balloon-like swelling in the retina's tiny blood vessels.
- Moderate nonproliferative retinopathy. As the diabetic retinopathy progresses, some blood vessels that nourish the retina are blocked.
- Severe nonproliferative retinopathy. In this stage of diabetic retinopathy, many more blood vessels are blocked, depriving several areas of the retina of blood. These areas of the retina send signals to the body to grow new blood vessels for nourishment.
- Proliferative retinopathy. At this advanced stage of diabetic retinopathy, the signals sent by the retina for nourishment trigger the growth of new blood vessels. This condition is called proliferative retinopathy. These new blood vessels are abnormal and fragile. They grow along the retina and along the surface of the clear, vitreous gel that fills the inside of the eye. By themselves, these blood vessels do not cause symptoms or vision loss. However, they have thin, fragile walls. If they leak blood, severe vision loss and even blindness can result.
Who's at Risk for Diabetic Retinopathy?
All people with
diabetes -- both type 1 and type 2 -- are at risk for diabetic retinopathy. That's why everyone with diabetes should get a comprehensive dilated eye exam at least once a year.
Between 40 percent to 45 percent of Americans diagnosed with diabetes have some stage of diabetic retinopathy. If you have diabetic retinopathy, your doctor can recommend treatment to help prevent its progression.
During pregnancy, diabetic retinopathy may be a problem for women with diabetes. To protect vision, every pregnant woman with diabetes should have a comprehensive dilated eye exam as soon as possible. Your doctor may recommend additional exams during your pregnancy.
Diabetic Retinopathy and Vision Loss
Blood vessels damaged from diabetic retinopathy can cause vision loss in two ways:
- Fragile, abnormal blood vessels can develop and leak blood into the center of the eye, blurring vision. This is proliferative retinopathy, the fourth (and most advanced stage) of the disease.
- Fluid can leak into the center of the macula, the part of the eye where sharp, straight-ahead vision occurs. The fluid makes the macula swell, blurring vision. This condition is called macular edema. It can occur at any stage of diabetic retinopathy, although it is more likely to occur as the disease progresses. About half of the people with proliferative retinopathy also have macular edema.
Symptoms of Diabetic Retinopathy
Diabetic retinopathy often has no early warning signs. Don't wait for diabetic retinopathy symptoms to appear. Be sure to have a comprehensive dilated eye exam at least once a year.
If diabetic retinopathy symptoms do appear, you will see a few specks of blood, or spots, "floating" in your vision. If spots occur, see your eye care professional as soon as possible. You may need
diabetic retinopathy treatment before more serious bleeding occurs. Hemorrhages tend to happen more than once, often during sleep.
Sometimes, without treatment, the spots clear, and your vision will improve; however, bleeding can recur and cause severely blurred vision. You need to be examined by your eye care professional at the first sign of blurred vision, before more bleeding occurs.
If left untreated, proliferative retinopathy can cause severe vision loss and even blindness. Also, the earlier you receive treatment, the more likely it will be effective.
Diagnosing Diabetic Retinopathy
Macular edema and diabetic retinopathy are detected during a comprehensive eye exam that includes:
- Visual acuity test. This eye chart test measures how well you see at various distances.
- Dilated eye exam. Drops are placed in your eyes to widen, or dilate, the pupils. Your eye care professional uses a special magnifying lens to examine your retina and optic nerve for signs of damage and other eye problems. After the exam, your close-up vision may remain blurred for several hours.
- Tonometry. An instrument measures the pressure inside the eye. Numbing drops may be applied to your eye for this test.
Your eye care professional checks your retina for early signs of diabetic retinopathy, including:
- Leaking blood vessels
- Retinal swelling (macular edema)
- Pale, fatty deposits on the retina -- signs of leaking blood vessels
- Damaged nerve tissue
- Any changes to the blood vessels.
If your eye care professional believes you need treatment for macular edema, he or she may suggest a fluorescein angiogram. In this test, a special dye is injected into your arm. Pictures are taken as the dye passes through the blood vessels in your retina. The test allows your eye care professional to identify any leaking blood vessels and recommend treatment.
Treating Diabetic Retinopathy
During the first three stages, no diabetic retinopathy treatment is needed, unless you have macular edema. To prevent progression of diabetic retinopathy, people with
diabetes should control their levels of:
For proliferative diabetic retinopathy, treatment may involve laser surgery or a
vitrectomy.
Diabetic Retinopathy: Protecting Vision
People with diabetes need to have a comprehensive dilated eye exam at least once a year. If you have diabetic retinopathy, you may need an eye exam more often. People with proliferative retinopathy can reduce their risk of blindness by 95 percent with timely treatment and appropriate followup care.
A major study has shown that better control of blood sugar levels slows the onset and progression of diabetic retinopathy. The people with diabetes who kept their blood sugar levels as close to normal as possible also had much less kidney and nerve disease. Better control also reduces the need for sight-saving laser surgery.
This level of blood sugar control may not be best for everyone, including some elderly patients, children under age 13, or people with
heart disease. Be sure to ask your doctor if such a control program is right for you.
Other studies have shown that controlling elevated blood pressure and cholesterol can reduce the risk of vision loss. Controlling these will help your overall health as well as help protect your vision.
Diabetic Retinopathy and Vision Loss
If you have lost some sight as a result of diabetic retinopathy, ask your eye care professional about low vision services and devices that may help you make the most of your remaining vision. Ask for a referral to a specialist in low vision. Many community organizations and agencies offer information about low vision counseling, training, and other special services for people with visual impairments. A nearby school of medicine or optometry may provide low vision services as well.
Questions to Ask About Diabetic Retinopathy
You can protect yourself against vision loss by working with your eye care professional. Ask questions and get the information you need to take care of yourself and your family.
You might want to ask your eye care professional the following questions about your diabetic retinopathy:
- What is my diagnosis?
- What caused my condition?
- Can my condition be treated?
- How will this condition affect my vision now and in the future?
- Should I watch for any particular symptoms and notify you if they occur?
- Should I make any lifestyle changes?
- What is the treatment for my condition?
- When will the treatment start and how long will it last?
- What are the benefits of this treatment? How successful is it?
- What are the risks and side effects associated with this diabetic retinopathy treatment?
- Are there foods, drugs, or activities I should avoid while I'm on this treatment?
- If my treatment includes taking medicine, what should I do if I miss a dose?
You should ask the following questions about tests available for diabetic retinopathy:
- What kinds of tests will I have?
- What can I expect to find out from these tests?
- When will I know the results?
- Do I have to do anything special to prepare for any of the diabetic retinopathy tests?
- Do these tests have any side effects or risks?
- Will I need more tests later?
Diabetic Retinopathy: Other Suggestions
Some other suggestions that people with diabetic retinopathy find helpful include:
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If you don't understand your eye care professional's responses, ask questions until you do understand.
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Take notes or get a friend or family member to take notes for you. Or, bring a tape recorder to help you remember the discussion.
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Ask your eye care professional to write down his or her instructions to you.
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Ask your eye care professional for printed material about your condition.
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If you still have trouble understanding your eye care professional's answers, ask where you can go for more information.
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Other members of your healthcare team, such as nurses and pharmacists, can be good sources of information. Talk to them as well.
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Be an active patient in your eye care.
Diabetic Retinopathy: Summary
The following points are important to keep in mind regarding diabetic retinopathy:
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If you have
diabetes, get a comprehensive dilated eye exam at least once a year.
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Proliferative diabetic retinopathy can develop without symptoms. At this advanced stage, you are at high risk for vision loss.
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Macular edema can develop without symptoms at any of the four stages of diabetic retinopathy.
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You can develop both proliferative retinopathy and macular edema and still see fine. However, you are at high risk for vision loss.
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Your eye care professional can tell if you have macular edema or any stage of diabetic retinopathy. Whether or not you have symptoms, early detection and timely treatment can prevent vision loss.
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