Diabetic retinopathy (die-uh-BET-ik ret-ih-NOP-uh-thee) is a diabetes complication that affects eyes. It's caused by 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, it can cause blindness.

The condition can develop in anyone who has type 1 or type 2 diabetes. The longer you have diabetes and the less controlled your blood sugar is, the more likely you are to develop this eye complication.

You might not have symptoms in the early stages of diabetic retinopathy. As the condition progresses, diabetic retinopathy symptoms may include:

  • Spots or dark strings floating in your vision (floaters)
  • Blurred vision
  • Fluctuating vision
  • Impaired color vision
  • Dark or empty areas in your vision
  • Vision loss

Diabetic retinopathy usually affects both eyes.

When to see a doctor

Careful management of your diabetes is the best way to prevent vision loss. If you have diabetes, see your eye doctor for a yearly eye exam with dilation — even if your vision seems fine. Pregnancy may worsen diabetic retinopathy, so if you're pregnant, your eye doctor may recommend additional eye exams throughout your pregnancy.

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

Over time, too much sugar in your blood can lead to the blockage of the tiny blood vessels that nourish the retina, cutting off its blood supply. As a result, the eye attempts to grow new blood vessels. But these new blood vessels don't develop properly and can leak easily.

There are two types of diabetic retinopathy:

  • Early diabetic retinopathy. In this more common form — called nonproliferative diabetic retinopathy (NPDR) — new blood vessels aren't growing (proliferating).

    When you have NPDR, the walls of the blood vessels in your retina weaken. Tiny bulges (microaneurysms) protrude from the vessel walls of the smaller vessels, sometimes leaking fluid and blood into the retina. Larger retinal vessels can begin to dilate and become irregular in diameter, as well. NPDR can progress from mild to severe, as more blood vessels become blocked.

    Nerve fibers in the retina may begin to swell. Sometimes the central part of the retina (macula) begins to swell (macular edema), a condition that requires treatment.

  • Advanced diabetic retinopathy. Diabetic retinopathy can progress to this more severe type, known as proliferative diabetic retinopathy. In this type, damaged blood vessels close off, causing the growth of new, abnormal blood vessels in the retina, and can 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), resulting in glaucoma.

Anyone who has diabetes can develop diabetic retinopathy. Risk of developing the eye condition can increase as a result of:

  • Duration of diabetes — the longer you have diabetes, the greater your risk of developing diabetic retinopathy
  • Poor control of your blood sugar level
  • High blood pressure
  • High cholesterol
  • Pregnancy
  • Tobacco use
  • Being black, Hispanic or Native American

Diabetic retinopathy involves the abnormal growth of blood vessels in the retina. Complications 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 (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 spots floating in your vision, flashes of light or severe vision loss.
  • Glaucoma. New blood vessels may grow in the front part of your eye and interfere with the normal flow of fluid out of the eye, causing pressure in the eye to build up (glaucoma). This pressure can damage the nerve that carries images from your eye to your brain (optic nerve).
  • Blindness. Eventually, diabetic retinopathy, glaucoma or both can lead to complete vision loss.

The American Diabetes Association (ADA) recommends that anyone who's older than 10 with type 1 diabetes have his or her first eye exam within five years of being diagnosed with diabetes.

If you have type 2 diabetes, the ADA advises getting your initial eye exam soon after being diagnosed with diabetes, because you may have had diabetes for some time without knowing it.

After the initial exam, the ADA recommends that people with diabetes get an annual eye exam. If you've had repeated normal exams and your blood sugar control is good, you may be able to extend the time between exams to two to three years. If you have retinopathy that's worsening, you may need more-frequent eye exams. Ask your eye doctor what he or she recommends.

The ADA recommends that women with diabetes who become pregnant have an eye exam during the first trimester of pregnancy and be closely followed during the pregnancy and up to one year after giving birth. Pregnancy can sometimes cause diabetic retinopathy to develop or worsen.

Here's some information to help you get ready for your eye appointment.

What you can do

  • Write a brief summary of your diabetes history, including when you were diagnosed; medications you have taken for diabetes, now and in the past; recent average blood sugar levels; and your last few hemoglobin A1C readings, if you know them.
  • List other medications, vitamins and supplements you take, and the dosage.
  • List your symptoms, if any. Include any that may seem unrelated to potential eye problems.
  • Ask a family member or friend to go with you, if possible. Someone who accompanies you can help remember the information you receive. Also, because your eyes have been dilated, a companion can drive you home.
  • List questions for your doctor.

For diabetic retinopathy, some basic questions to ask your doctor include:

  • How is diabetes affecting my vision?
  • Do I need other tests?
  • Is this condition temporary or long lasting?
  • What treatments are available, and which do you recommend?
  • What side effects might I expect from treatment?
  • I have other health conditions. How can I best manage them together?
  • If I control my blood sugar, will my eye symptoms go away?
  • What do my blood sugar goals need to be to protect my eyes?
  • Can you recommend services for people with visual impairment?

Don't hesitate to ask other questions you have.

What to expect from your doctor

Your doctor is likely to ask you a number of questions, including:

  • Do you have eye symptoms, such as blurred vision or floaters?
  • How long have you had symptoms?
  • In general, how well are you controlling your diabetes?
  • What was your last hemoglobin A1C?
  • Do you have other health conditions, such as high blood pressure or high cholesterol?
  • Have you had eye surgery?

Diabetic retinopathy is best diagnosed with a dilated eye exam. For this exam, drops placed in your eyes widen (dilate) your pupils to allow your doctor to better view inside your eyes. The drops may cause your close vision to blur until they wear off, several hours later.

During the exam, your eye doctor will look for:

  • Abnormal blood vessels
  • Swelling, blood or fatty deposits in the retina
  • 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
  • Abnormalities in your optic nerve

In addition, your eye doctor may:

  • Test your vision
  • Measure your eye pressure to test for glaucoma
  • Look for evidence of cataracts

Fluorescein angiography

With your eyes dilated, your doctor takes pictures of the inside of your eyes. Then your doctor will inject a special dye into your arm and take more pictures 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.

Optical coherence tomography

Your eye doctor 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, which will help determine whether fluid has leaked into retinal tissue. Later, OCT exams can be used to monitor how treatment is working.

Treatment, which depends largely on the type of diabetic retinopathy you have and how severe it is, is geared to slowing or stopping progression of the condition.

Early diabetic retinopathy

If you have mild or moderate nonproliferative diabetic retinopathy, you may not need treatment right away. However, your eye doctor will closely monitor your eyes to determine when you might need treatment.

Work with your diabetes doctor (endocrinologist) to determine if there are ways to improve your diabetes management. When diabetic retinopathy is mild or moderate, good blood sugar control can usually slow the progression.

Advanced diabetic retinopathy

If you have proliferative diabetic retinopathy or macular edema, you'll need prompt surgical treatment. Depending on the specific problems with your retina, options may include:

  • Focal laser treatment. This laser treatment, also known as photocoagulation, can stop or slow the leakage of blood and fluid in the eye. During the procedure, leaks from abnormal blood vessels are treated with laser burns.

    Focal laser treatment is usually done in your doctor's office or eye clinic in a single session. If you had blurred vision from macular edema before surgery, the treatment might not return your vision to normal, but it's likely to reduce the chance the macular edema may worsen.

  • Scatter laser treatment. This laser treatment, also known as panretinal photocoagulation, can shrink the abnormal blood vessels. During the procedure, the areas of the retina away from the macula are treated with scattered laser burns. The burns cause the abnormal new blood vessels to shrink and scar.

    It's usually done in your doctor's office or eye clinic 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 uses a tiny incision in your eye to remove blood from the middle of the eye (vitreous) as well as scar tissue that's tugging on the retina. It's done in a surgery center or hospital using local or general anesthesia.

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 are still 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 swelling or abnormal blood vessels. These treatments appear promising, but more study is needed.

Several alternative therapies have suggested some benefits for people with diabetic retinopathy, but more research is needed to understand whether these treatments are effective and safe.

Be sure to let your doctor know if you are taking any herbs or supplements. They have the potential to interact with other medications, or cause complications in surgery, such as excessive bleeding.

It's vital not to delay standard treatments to try unproven therapies. Early treatment is the best way to prevent vision loss.

The thought that you might lose your sight can be frightening, and you may benefit from talking to a therapist or finding a support group. Ask your doctor for referrals.

If you've already lost vision, ask your doctor about low-vision products, such as magnifiers, and services that can make daily living easier.

You can't always prevent diabetic retinopathy. However, regular eye exams, good control of your blood sugar and blood pressure, and early intervention for vision problems can help prevent severe vision loss.

If you have diabetes, reduce your risk of getting diabetic retinopathy by doing the following:

  • Manage your diabetes. Make healthy eating and physical activity part of your daily routine. Try to get at least 150 minutes of moderate aerobic activity, such as walking, each week. Take oral diabetes medications or insulin as directed.
  • Monitor your blood sugar level. You may need to check and record your blood sugar level several times a day — more-frequent measurements may be required if you're ill or under stress. Ask your doctor how often you need to test your blood sugar.
  • Ask your doctor about a glycosylated hemoglobin test. The glycosylated hemoglobin test, or hemoglobin A1C test, reflects your average blood sugar level for the two- to three-month period before the test. For most people, the A1C goal is to be under 7 percent.
  • Keep your blood pressure and cholesterol under control. 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.
  • Pay attention to vision changes. 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 lead to vision loss. Taking an active role in diabetes management can go a long way toward preventing complications.

March 20, 2015