Diabetic retinopathy

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Diabetic retinopathy

Definition
Diabetic retinopathy is a complication of diabetes that results from damage to the blood vessels of the light-sensitive tissue at the back of the eye (retina). At first, diabetic retinopathy may cause no symptoms or only mild vision problems. Eventually, however, diabetic retinopathy can result in blindness. In the United States, diabetic retinopathy is a leading cause of blindness in adults.

Diabetic retinopathy can happen to anyone who has type 1 diabetes or type 2 diabetes. In fact, up to 45 percent of adults diagnosed with diabetes in the United States have some degree of diabetic retinopathy, according to the National Eye Institute. And the longer you have diabetes, the more likely you are to develop diabetic retinopathy.

To protect your vision, take prevention seriously. Start by controlling your blood sugar level and scheduling yearly eye exams.

Symptoms
You can have diabetic retinopathy and not know it. In fact, symptoms are unusual in the early stages of diabetic retinopathy.

As the condition progresses, diabetic retinopathy symptoms may include:

Spots floating in your vision
Blurred vision
Dark streaks or a red film that blocks your vision
Poor night vision
Vision loss
Diabetic retinopathy usually affects both eyes.

Causes

When you have diabetes, your body doesn't use sugar (glucose) properly. If your blood sugar level is too high, your natural lens may swell Û which can blur your vision. Eventually, too much sugar in your blood can damage the tiny blood vessels (capillaries) that nourish the retina. This can result in diabetic retinopathy.

Diabetic retinopathy is usually classified as early or advanced.

Early diabetic retinopathy. Nonproliferative diabetic retinopathy (NPDR) is the most common type of diabetic retinopathy. It can be described as mild, moderate or severe. When you have NPDR, the walls of the blood vessels in your retina weaken. Tiny bulges protrude from the vessel walls, sometimes leaking or oozing fluid and blood into the retina. These bulges are called microaneurysms. As the condition progresses, the smaller vessels may close entirely and the larger retinal veins may begin to dilate and become irregular in diameter. Nerve fibers in the retina may begin to swell. Sometimes the central part of the retina (macula) begins to swell, too. This is known as macular edema.
Advanced diabetic retinopathy. Proliferative diabetic retinopathy (PDR) is the most severe type of diabetic retinopathy. When you have PDR, abnormal blood vessels grow in the retina. Sometimes the new blood vessels grow or leak into the clear, jelly-like substance that fills the center of your eye (vitreous). Eventually, scar tissue stimulated by the growth of new blood vessels may cause the retina to detach from the back of your eye. If the new blood vessels interfere with the normal flow of fluid out of the eye, pressure may build up in the eyeball. This can damage the nerve that carries images from your eye to your brain (optic nerve).
Risk factors
Diabetic retinopathy can happen to anyone who has diabetes. The risk is highest if you:

Have poor control of your blood sugar level
Have high blood pressure
Have high cholesterol
Are pregnant
Are black or Hispanic
Smoke
The longer you have diabetes, the greater your risk of developing diabetic retinopathy.

When to seek medical advice
Early detection of diabetic retinopathy is the best way to prevent vision loss. If you have diabetes, see your eye doctor for a yearly dilated eye exam Û even if your vision seems fine. If you become pregnant, your eye doctor may recommend additional eye exams throughout your pregnancy.

Contact your eye doctor right away if you experience sudden vision changes or your vision becomes blurry, spotty or hazy.

Tests and diagnosis
Diabetic retinopathy is best diagnosed with a dilated eye exam. During the exam, your eye doctor will look for:

Abnormal blood vessels
Swelling, blood or fatty deposits in the retina
Damage to the nerve tissue
Growth of new blood vessels and scar tissue
Bleeding in the clear, jelly-like substance that fills the center of the eye (vitreous)
Retinal detachment
As part of the eye exam, your doctor may do a retinal photography test called fluorescein angiography. First, your doctor will dilate your pupils and take pictures of the inside of your eyes. Then a special dye will be injected into a vein in your arm. More pictures will be taken as the dye circulates through your eyes. Your doctor can use the images to pinpoint blood vessels that are closed, broken down or leaking fluid.

Your doctor also may request an optical coherence tomography (OCT) exam. This imaging test provides cross-sectional images of the retina that show the thickness of the retina and whether fluid has leaked into retinal tissue. Later, OCT exams can be used to monitor treatment effectiveness.

Complications
The abnormal growth of new blood vessels in the retina can lead to serious vision problems:

Vitreous hemorrhage. The new blood vessels may bleed into the clear, jelly-like substance that fills the center of your eye. If the amount of bleeding is small, you might see only a few dark spots or floaters. In more severe cases, blood can fill the vitreous cavity and completely block your vision. Vitreous hemorrhage by itself usually doesn't cause permanent vision loss. The blood often clears from the eye within a few weeks or months. Unless your retina is damaged, your vision may return to its previous clarity.
Retinal detachment. The abnormal blood vessels associated with diabetic retinopathy stimulate the growth of scar tissue, which can pull the retina away from the back of the eye. This may cause blurred vision, spots floating in your vision or severe vision loss.
Glaucoma. The new blood vessels may interfere with the normal flow of fluid out of the eye and cause pressure in the eye to build up. This pressure can damage the nerve that carries images from your eye to your brain (optic nerve).
Blindness. Eventually, diabetic retinopathy can lead to complete vision loss.
Treatments and drugs
Treatment for diabetic retinopathy depends on the type of diabetic retinopathy you have, its severity and how well it may respond to specific treatments.

Early diabetic retinopathy
If you have nonproliferative diabetic retinopathy, you may not need treatment right away. However, your eye doctor will closely monitor your retina to determine if you need laser treatment.

Advanced diabetic retinopathy
If you have proliferative diabetic retinopathy, you'll need prompt surgical treatment. Sometimes surgery is recommended for severe nonproliferative diabetic retinopathy, too. Depending on the specific problems with your retina, options may include:

Focal laser treatment. This laser treatment, also known as photocoagulation, can stop the leakage of blood and fluid in the eye. It's done in your doctor's office or eye clinic. During the procedure, leaks from abnormal blood vessels are sealed with laser burns. Focal laser treatment is usually done in a single session. Your vision will be blurry for about a day after the procedure. Sometimes small spots caused by the laser burns may appear in your visual field. The spots generally fade and disappear with time. If you had blurred vision from swelling of the central macula before surgery, however, you may not recover completely normal vision.
Scatter laser treatment. This laser treatment, also known as panretinal photocoagulation, can shrink the abnormal blood vessels. It's also done in your doctor's office or eye clinic. During the procedure, the areas of the retina away from the macula are treated with scattered laser burns. The burns cause the new blood vessels to shrink and disappear. Scatter laser treatment is usually done in two or more sessions. Your vision will be blurry for about a day after the procedure. Some loss of peripheral vision or night vision after the procedure is possible.
Vitrectomy. This procedure can be used to remove blood from the center of the eye (vitreous) and scar tissue that's tugging on the retina. It's done in a surgery center or hospital under local or general anesthesia. During the procedure, the doctor makes a tiny incision in your eye. The blood-filled tissue and scar tissue are removed with delicate instruments and replaced with a salt solution, which helps maintain your eye's normal shape. Sometimes a gas bubble must be placed in the cavity of the eye to help reattach the retina. After surgery, you may stay in the hospital overnight. If a gas bubble was placed in your eye, you may need to remain in a facedown position until the gas bubble disappears Û often several days. You'll need to wear an eye patch and use medicated eyedrops for a few days or weeks. Often, vitrectomy is followed or accompanied by laser treatment.
Surgery often slows or stops the progression of diabetic retinopathy, but it's not a cure. Because diabetes is a lifelong condition, future retinal damage and vision loss is possible. Even after treatment for diabetic retinopathy, you'll need regular eye exams. At some point, additional treatment may be recommended.

Researchers are studying new treatments for diabetic retinopathy, including medications that may help prevent abnormal blood vessels from forming in the eye. Some of these medications are injected directly into the eye to treat existing swelling or abnormal blood vessels.

Prevention
The longer you have diabetes, the greater your risk of developing diabetic retinopathy Û but there's much you can do to promote healthy vision.

Make a commitment to managing your diabetes. Make healthy eating and physical activity part of your daily routine. Take oral diabetes medications or insulin as directed.
Monitor your blood sugar level. You may need to check and record your blood sugar level at least several times a day Û or more if you're ill or under stress. Careful monitoring is the only way to make sure that your blood sugar level remains within your target range.
Ask your doctor about a glycated hemoglobin test. This test, also called a glycosylated hemoglobin test or hemoglobin A1C test, reflects your average blood sugar level for the two- to three-month period before the test. Remember, keeping your blood sugar level as close to normal as possible slows the progression of diabetic retinopathy and reduces the need for surgery.
Keep your blood pressure and cholesterol under control. High blood pressure and high cholesterol increase the risk of vision loss. Eating healthy foods, exercising regularly and losing excess weight can help. Sometimes medication is needed, too.
If you smoke or use other types of tobacco, ask your doctor to help you quit. Smoking increases your risk of various diabetes complications, including diabetic retinopathy. Talk to your doctor about ways to stop smoking or to stop using other types of tobacco.
Take stress seriously. If you're stressed, it's easy to abandon your usual diabetes management routine. The hormones your body may produce in response to prolonged stress may prevent insulin from working properly, which only makes matters worse. To take control, set limits. Prioritize your tasks. Learn relaxation techniques. Get plenty of sleep.
Pay attention to vision changes. Yearly dilated eye exams are an important part of your diabetes treatment plan. Contact your eye doctor right away if you experience sudden vision changes or your vision becomes blurry, spotty or hazy.
Remember, diabetes doesn't necessarily doom you to poor vision. Taking an active role in diabetes management can go a long way toward preventing complications.

By the Mayo Clinic Staff