If you have diabetes mellitus, you know how your body's inability to use and store sugar can affect your health. When your blood sugar gets too high, it can damage the blood vessels in your eyes. This damage may lead to diabetic retinopathy.
What is diabetic retinopathy?
Diabetic retinopathy is the most common diabetic eye disease and a leading cause of blindness in American adults. It is caused by changes in the blood vessels of the retina. In some people with diabetic retinopathy, blood vessels may swell and leak fluid. In other people, abnormal new blood vessels grow on the surface of the retina. The retina is 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 not notice changes to your vision. But over time, diabetic retinopathy can get worse and cause vision loss. Diabetic retinopathy usually affects both eyes.
What are the stages of diabetic retinopathy?
Diabetic retinopathy has four stages:
- Mild Nonproliferative Retinopathy: At this earliest stage, microaneurysms occur. They are small areas of balloon-like swelling in the retina's tiny blood vessels.
- Moderate Nonproliferative Retinopathy: As the disease progresses, some blood vessels that nourish the retina are blocked.
- Severe Nonproliferative Retinopathy: Many more blood vessels are blocked, depriving several areas of the retina with their blood supply. 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 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.
What are the types of diabetic retinopathy?
When the blood vessels in the retina are damaged, they can leak fluid or bleed. This causes the retina to swell and form deposits called exudates. This is an early form of diabetic retinopathy called non-proliferative or background retinopathy. You may not notice any change in your vision when you develop this early form of the disease, but it can lead to other more serious forms of retinopathy that may affect your vision.
When fluid collects in the macula, reading and other close work may become difficult. This is called macular edema. In proliferative retinopathy, new, fragile blood vessels grow on the surface of the retina. These new blood vessels are called neovascularization, and can lead to serious vision problems, because the new vessels can break and bleed into the vitreous. When the vitreous becomes clouded with blood, light is prevented from passing through the eye to the retina. This can blur or distort vision. The new blood vessels can also cause scar tissue to develop, which can pull the retina away from the back of the eye. This is known as a retinal detachment, and can lead to blindness if untreated. In addition, abnormal blood vessels can grow on the iris.
What are the symptoms of diabetic retinopathy?
Although diabetic retinopathy can severely damage your vision, it is not painful. In fact, the early form of the disease called non-proliferative or background retinopathy often produces no symptoms.
- If non-proliferative retinopathy leads to macular edema, you may notice a gradual blurring of your vision, and have difficulty doing close work such as reading.
- If the abnormal blood vessels associated with proliferative retinopathy bleed, vision may become spotty, hazy, or disappear completely.
However, because diabetic retinopathy often causes no symptoms even in advanced cases it is extremely important to have a yearly dilated eye exam by an ophthalmologist. Diabetic retinopathy can be treated, and vision loss possibly prevented if it is caught early enough.
How is diabetic retinopathy treated?
During the first three stages of diabetic retinopathy, no treatment is needed, unless you have macular edema. To prevent progression of diabetic retinopathy, people with diabetes should control their levels of blood sugar, blood pressure, and blood cholesterol.
Proliferative retinopathy is treated with laser surgery. This procedure is called scatter laser treatment. Scatter laser treatment helps to shrink the abnormal blood vessels. Your doctor places 1,000 to 2,000 laser burns in the areas of the retina away from the macula, causing the abnormal blood vessels to shrink. Because a high number of laser burns are necessary, two or more sessions usually are required to complete treatment. Although you may notice some loss of your side vision, scatter laser treatment can save the rest of your sight. Scatter laser treatment may slightly reduce your 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. Even if bleeding has started, scatter laser treatment may still be possible, depending on the amount of bleeding.
If the bleeding is severe, you may need a surgical procedure called a vitrectomy. During a vitrectomy, blood is removed from the center of your eye.