Diabetic Eye Disease

What is diabetic eye disease?

Diabetic eye disease is a group of eye problems that can happen in people with diabetes. All of these problems can cause severe vision loss or even blindness.

The most common diabetic eye disease is diabetic retinopathy. But diabetic eye disease can include other eye problems such as:

  • Cataract – This is a clouded area in the eye's lens. While many people get cataracts as they age, they happen at an earlier age in people with diabetes.
  • Glaucoma – This is damage of the optic nerve and loss of vision. It is usually associated with an increase in fluid pressure inside the eye. A person with diabetes is nearly twice as likely to get glaucoma.

What is diabetic retinopathy?

Diabetic retinopathy is the most common diabetic eye disease and a leading cause of blindness in adults in the U.S. It is caused by changes in the blood vessels of the retina. The retina is the light-sensitive tissue at the back of the eye. A healthy retina is necessary for good vision.

In some people with diabetic retinopathy, blood vessels might swell and leak fluid. In other people, abnormal blood vessels grow on the surface of the retina. Diabetic retinopathy usually affects both eyes.

If you have diabetic retinopathy, you might not notice changes to your vision at first. But over time, diabetic retinopathy can worsen and cause vision loss.

What are the stages of diabetic retinopathy?

There are four stages of diabetic retinopathy. They are:

  • Mild non-proliferative retinopathy – This is the earliest stage. People in this stage have small areas of balloon-like swelling in the retina's tiny blood vessels. These are called microaneurysms.
  • Moderate non-proliferative retinopathy – In this second stage, blood vessels that nourish the retina become blocked.
  • Severe non-proliferative retinopathy – In this third stage, many more blood vessels are blocked. This keeps several areas of the retina from receiving the blood supply they need. These areas of the retina send signals to the body to grow new blood vessels for nourishment.
  • Proliferative retinopathy - At this advanced stage, the signals sent by the retina in the third stage trigger the growth of new blood vessels. These new blood vessels are fragile and break easily. They grow along the retina and along the surface of the clear, vitreous gel that fills the inside of the eye. On their own, these blood vessels do not cause symptoms or vision loss. But if they break and leak blood, they can cause severe vision loss and even blindness.

How does diabetic retinopathy cause vision loss?

Diabetic retinopathy changes the blood vessels in the retina. This can cause vision loss in two ways:

  • Proliferative retinopathy  - This is when fragile, abnormal blood vessels develop and leak blood into the center of the eye, blurring vision. It happens in the fourth and most advanced stage of the disease.
  • Macular edema  - This is when fluid leaks into the center of the macula, the part of the eye that allows for central vision. Central vision is the sharp, straight-ahead vision needed to see fine detail. When fluid leaks into the macula, it causes swelling and blurs vision. Macular edema can happen at any stage of diabetic retinopathy, although it is more likely to happen as the disease worsens. About half of the people with proliferative retinopathy also have macular edema.

You can develop either proliferative retinopathy, macular edema, or both and still have no symptoms or vision loss. However, if you have these conditions you are at high risk for vision loss. Your eye doctor 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.

Who is at risk for diabetic retinopathy?

The main risk factor for diabetic retinopathy is diabetes. This includes both type 1 and type 2 diabetes.

The longer a person has diabetes, the more likely he or she will get diabetic retinopathy. Between 40 to 45 percent of Americans diagnosed with diabetes have some stage of diabetic retinopathy. For this reason, everyone with diabetes should get a comprehensive dilated eye exam at least once a year.

Women with diabetes who become pregnant are also at higher risk of diabetic retinopathy. To protect vision, every pregnant woman with diabetes should have a comprehensive dilated eye exam as soon as possible. Your doctor might recommend additional exams during your pregnancy.

What can I do to protect my vision?

If you have diabetes, make sure to get a comprehensive dilated eye exam at least once a year.

If you have diabetic retinopathy, you might need an eye exam more often. People with proliferative retinopathy can reduce their risk of blindness by 95 percent with early treatment and good follow-up care.

Controlling your blood sugar levels can slow the onset and worsening of your retinopathy. Better blood sugar control also reduces the need for laser surgery to save vision. But the same level of blood sugar control might not be best for everyone, such as some elderly people, children under age 13, or people with heart disease. Be sure to ask your doctor if a control program is right for you.

Controlling elevated blood pressure and cholesterol might also reduce the risk of vision loss. This can help your overall health as well as your vision.

Does diabetic retinopathy have any symptoms?

Early on, the disease often does not cause symptoms or pain. If macular edema happens, it might cause blurred vision. But don't wait for symptoms. Be sure to have a comprehensive dilated eye exam at least once a year.

If new blood vessels grow on the surface of the retina, they can bleed into the eye and block vision. This causes symptoms. You might start to see a few specks of blood, or spots, "floating" in your vision. Episodes of bleeding tend to happen more than once, often during sleep. If these occur, see your eye care professional as soon as possible. You might need treatment to stop more serious bleeding from happening.

Sometimes, the spots stop without treatment. However, bleeding can start again and cause severely blurred vision. You need to be examined by your eye doctor at the first sign of blurred vision, before more bleeding happens. If left untreated, diabetic retinopathy can cause severe vision loss and even blindness. Also, the earlier you receive treatment, the more likely treatment will be effective.

How are diabetic retinopathy and macular edema detected?

Diabetic retinopathy and macular edema are detected during a comprehensive eye exam. This includes:

  • Visual acuity test – This test uses an eye chart to measure how well you see at various distances.
  • Dilated eye exam – For this test, the eye doctor puts drops in your eyes to widen, or dilate, the pupils. He or she will then use a special magnifying lens to examine your retina and optic nerve for signs of disease and other eye problems. After the exam, your close-up vision might remain blurred for several hours.
  • Tonometry – This test involves an instrument that measures the pressure inside the eye. Your doctor might apply numbing drops to your eye for this test.

If you need treatment for macular edema, your doctor might suggest you have a fluorescein angiogram. For this test, a special dye is injected into your arm. Pictures are taken as the dye passes through the blood vessels in your retina. This allows your eye doctor to see any leaking blood vessels and decide how to treat them.

How is diabetic retinopathy treated?

People in the first three stages of diabetic retinopathy, do not need treatment unless they have macular edema. To prevent diabetic retinopathy from getting worse, people with diabetes should control their blood sugar levels, blood pressure, and blood cholesterol.

People in later stages of the disease, or who have macular edema, will need treatment. Treatment options depend on the type of diabetic retinopathy. They include:

  • Scatter laser treatment – This is a kind of laser surgery for people with proliferative retinopathy. Scatter laser treatment helps to shrink the abnormal blood vessels. For this treatment, the doctor places 1000 to 2000 laser burns in the areas of the retina away from the macula. This causes the abnormal blood vessels to shrink. Because a high number of laser burns are necessary, a person who gets this treatment usually needs two or more sessions. Scatter laser treatment can cause some loss of peripheral (side) vision, but it can preserve and save the rest of the person's vision, especially critical central vision. It might also slightly reduce color vision and night vision.

    Scatter laser treatment works better before the fragile, new blood vessels have started to bleed. That is why it is important to have regular, comprehensive dilated eye exams. Once some bleeding has started, it is important to have scatter laser treatment as soon as possible. This is because floating blood can prevent your eye doctor from being able to see your retina well.

  • Vitrectomy – This is a surgical procedure for people with severe bleeding. During a vitrectomy, the doctor removes blood from the center of the eye. If you have this treatment, you will probably also have scatter laser treatment at the same time.
  • Focal laser treatment – This is a kind of laser surgery for people with macular edema. For this treatment, the doctor places small laser burns directly in the areas of retinal leakage surrounding the macula. These burns slow the leakage of fluid and reduce the amount of fluid in the retina.

    The surgery is usually completed in one session, but a person might need focal laser surgery more than once to control leaking fluid. If surgery is needed for macular edema is in both eyes, generally only one eye will be treated at a time, usually several weeks apart.

    Focal laser treatment not only preserves vision, but it reduces the risk of vision loss by 50 percent. In a few cases, lost vision can even be improved.

  • Medications – If you have macula edema, your eye doctor might give you injections of medications such as ranibizumab, bevacizumab and steroids. You will have these injections in your eye doctor's office, once he or she has cleaned and numbed your eye. These medications can help by decreasing fluid and swelling in the macula without the risk of scarring from laser burns. Treatment with injections usually requires multiple treatments.

What happens during laser treatment?

Both focal and scatter laser treatment are performed in your doctor's office or eye clinic.

Before the surgery, your doctor will dilate your pupil and apply drops to numb the eye. The area behind your eye might also be numbed to prevent discomfort. You will sit facing the laser machine and your doctor will hold a special lens to your eye. During the procedure, you might see flashes of light. These flashes might create a stinging sensation that can be uncomfortable over time.

You will need someone to drive you home after surgery. Because your pupil will stay dilated for a few hours, you should bring a pair of sunglasses. For the rest of the day, your vision will probably be a little blurry. If your eye hurts, your doctor can suggest treatment.

Laser surgery and good follow-up care can reduce the risk of blindness by 90 percent. However, laser surgery usually cannot restore vision that has already been lost. That is why treating diabetic retinopathy early is the best way to prevent vision loss.

What happens during a vitrectomy?

A vitrectomy is performed under either local or general anesthesia. Your doctor makes a tiny incision in your eye and uses a small instrument to remove the vitreous gel that is clouded with blood. He or she then replaces the cloudy vitreous gel with a salt solution. Because the vitreous gel is mostly water, you won't notice any change between the salt solution and the original vitreous gel.

Once the vitrectomy is finished, you will probably be able to return home right away, but some people need to stay in the hospital overnight after having this treatment. Your eye will be red and sensitive. You will need to wear an eye shield for a few days or weeks to protect your eye. You will also need to use medicated eyedrops to protect your eyes from infection and inflammation.

Can scatter laser treatment and vitrectomy cure diabetic retinopathy?

No, but both treatments are very good at reducing vision loss. People with proliferative retinopathy have less than a 5 percent chance of becoming blind within five years when they get timely and appropriate treatment.

Once you have proliferative retinopathy, you will always be at risk for new bleeding. You might need treatment more than once to protect your sight.

What can I do if I already have lost some vision from diabetic retinopathy?

If you have lost some sight from diabetic retinopathy, ask your eye doctor about low vision services and devices that can help you make the most of the vision you have left. Ask him or her to refer you 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 might provide low vision services.