Facts About Diabetic Eye Disease
What is diabetic eye disease?
Diabetic eye disease refers to a group of eye problems that people with diabetes may face as a complication of this disease. All can cause severe vision loss or even blindness.
Diabetic eye disease includes:
- Diabetic retinopathy: Damage to the blood vessels in the retina.
- Cataract: Clouding of the lens of the eye.
- Glaucoma: Increase in fluid pressure inside the eye that leads to optic nerve damage and loss of vision.
What is the most common diabetic eye disease?
Diabetic retinopathy. This disease is 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, retinal blood vessels may swell and leak fluid. In other people, abnormal new blood vessels grow on the surface of the retina. These changes may result in vision loss or blindness.
What are its symptoms?
There are often no symptoms in the early stages of diabetic retinopathy. There is no pain and vision may not change until the disease becomes severe. Blurred vision may occur when the macula (the part of the retina that provides sharp, central vision) swells from the leaking fluid. This condition is called macular edema. If new vessels have grown on the surface of the retina, they can bleed into the eye, blocking vision. Even in more advanced cases, the disease may progress a long way without symptoms. This symptomless progression is why regular eye examinations for people with diabetes are so important.
Who is most likely to get diabetic retinopathy?
Anyone with diabetes. The longer someone has diabetes, the more likely he or she will get diabetic retinopathy. Between 40-45 percent of those with diagnosed diabetes have some degree of diabetic retinopathy.
How is diabetic retinopathy detected?
If you have diabetes, you should have your eyes examined at least once a year. Your eyes should be dilated during the exam, which means eyedrops are used to enlarge your pupils. This dilation allows the eye care professional to see more of the inside of your eyes to check for signs of the disease.
What causes diabetic retinopathy?
Chronically high blood sugar from diabetes is associated with damage to the tiny blood vessels in the retina, leading to diabetic retinopathy. The retina detects light and converts it to signals sent through the optic nerve to the brain. Diabetic retinopathy can cause blood vessels in the retina to leak fluid or hemorrhage (bleed), distorting vision. In its most advanced stage, new abnormal blood vessels proliferate (increase in number) on the surface of the retina, which can lead to scarring and cell loss in the retina.
Diabetic retinopathy may progress through four stages:
- Mild nonproliferative retinopathy. Small areas of balloon-like swelling in the retina’s tiny blood vessels, called microaneurysms, occur at this earliest stage of the disease. These microaneurysms may leak fluid into the retina.
- Moderate nonproliferative retinopathy. As the disease progresses, blood vessels that nourish the retina may swell and distort. They may also lose their ability to transport blood. Both conditions cause characteristic changes to the appearance of the retina and may contribute to DME.
- Severe nonproliferative retinopathy. Many more blood vessels are blocked, depriving blood supply to areas of the retina. These areas secrete growth factors that signal the retina to grow new blood vessels.
- Proliferative diabetic retinopathy (PDR). At this advanced stage, growth factors secreted by the retina trigger the proliferation of new blood vessels, which grow along the inside surface of the retina and into the vitreous gel, the fluid that fills the eye. The new blood vessels are fragile, which makes them more likely to leak and bleed. Accompanying scar tissue can contract and cause retinal detachment—the pulling away of the retina from underlying tissue, like wallpaper peeling away from a wall. Retinal detachment can lead to permanent vision loss.
What is diabetic macular edema (DME)?
DME is the build-up of fluid (edema) in a region of the retina called the macula. The macula is important for the sharp, straight-ahead vision that is used for reading, recognizing faces, and driving. DME is the most common cause of vision loss among people with diabetic retinopathy. About half of all people with diabetic retinopathy will develop DME. Although it is more likely to occur as diabetic retinopathy worsens, DME can happen at any stage of the disease.
Who is at risk for diabetic retinopathy?
People with all types of diabetes (type 1, type 2, and gestational) are at risk for diabetic retinopathy. Risk increases the longer a person has diabetes. Between 40 and 45 percent of Americans diagnosed with diabetes have some stage of diabetic retinopathy, although only about half are aware of it. Women who develop or have diabetes during pregnancy may have rapid onset or worsening of diabetic retinopathy.
Prevention and Treatment
Can diabetic retinopathy be treated?
Yes. Your eye care professional may suggest laser surgery in which a strong light beam is aimed onto the retina.
Laser surgery and appropriate followup care can reduce the risk of blindness by 90 percent. However, laser surgery often cannot restore vision that has already been lost, which is why finding diabetic retinopathy early is the best way to prevent vision loss.
Can diabetic retinopathy be prevented?
Not totally, but your risk can be greatly reduced. The Diabetes Control and Complications Trial (DCCT) showed that better control of blood sugar level slows the onset and progression of retinopathy and lessens the need for laser surgery for severe retinopathy.
The study found that the group that tried to keep their blood sugar levels as close to normal as possible also had much less kidney and nerve disease. This level of blood sugar control may not be best for everyone, including some older adults, children under 13, or people with heart disease. So ask your doctor if this program is right for you.
How common are the other diabetic eye diseases?
If you have diabetes, you are also at risk for other diabetic eye diseases, such as cataract and glaucoma. People with diabetes develop cataract at an earlier age than people without diabetes. Cataract can usually be treated by surgery.
A person with diabetes is nearly twice as likely to get glaucoma as other adults. And, as with diabetic retinopathy, the longer you have had diabetes, the greater your risk of getting glaucoma. Glaucoma may be treated with medications, laser surgery, or conventional surgery.
What research is being done?
Much research is being done to learn more about diabetic eye disease. For instance, the National Eye Institute is supporting a number of research studies in the laboratory and with patients to learn what causes diabetic retinopathy and how it can be better treated. This research should provide better ways to detect and treat diabetic eye disease and prevent blindness in more people with diabetes.
What can you do to protect your vision?
Finding and treating the disease early, before it causes vision loss or blindness, is the best way to control diabetic eye disease. So if you have diabetes, make sure you get a comprehensive dilated eye examination at least once a year.
Diabetes is a disease that can cause very serious health problems. If you have diabetes:
- Know your ABCs: A1C (blood glucose), blood pressure (BP), and cholesterol numbers.
- Take your medicines as prescribed by your doctor.
- Monitor your blood sugar daily.
- Reach and stay at a healthy weight.
- Get regular physical activity.
- Quit smoking.
The National Eye Institute (NEI) is part of the National Institutes of Health (NIH) and is the Federal government’s lead agency for vision research that leads to sight-saving treatments and plays a key role in reducing visual impairment and blindness.