Diabetic Eye Disease
How can diabetes affect my eyes?
Too much glucose, also called sugar, in your blood from diabetes can damage four parts of your eye:
- Retina. The retina is the tissue that lines the back of your eye. The retina converts light coming into your eye into visual messages through the optic nerve to your brain. The macula is the small, sensitive, center part of the retina that gives sharp, detailed vision.
- Lens. The lens of your eye is clear and is located behind the iris, the colored part of your eye. The lens helps to focus light, or an image, on the retina.
- Vitreous gel. The vitreous gel is a clear, colorless mass that fills the rear of your eye, between the retina and lens.
- Optic nerve. The optic nerve, at the back of your eye, is your eye’s largest sensory nerve. The optic nerve connects your eye to your brain, carries visual messages from the retina to your brain, and sends messages between your brain and your eye muscles.
Diabetes damage to your eyes—called diabetic eye disease—can cause permanent vision loss, including low vision and blindness. Low vision means that even with regular glasses, contact lenses, medicine, or surgery, you can’t see well enough to easily complete everyday tasks.
How does diabetes affect the retina?
Over time, having high blood glucose levels from diabetes can damage the tiny blood vessels on the retina. Diabetic retinopathy is the medical term for damage to the retina from diabetes.
Retina damage happens slowly. First, the retina’s blood vessels swell. As retina damage worsens, the blood vessels become blocked and cut off the retina’s oxygen supply. In response, new, weak blood vessels grow on the retina and the surface of the vitreous gel. These blood vessels break easily and leak blood into the vitreous gel. The leaking blood keeps light from reaching the retina.
When that happens, you may see floating spots or almost total darkness. One of your eyes may be damaged more than the other, or both eyes may have the same amount of damage. Sometimes the blood clears out by itself. However, you might need surgery to remove the blood.
You might not have any problems with your vision until the damage is severe, so you should have an eye exam at least once a year, even if your vision seems fine. Call your eye doctor right away if you notice any changes in your vision.
Over the years, the swollen and weak blood vessels can form scar tissue and pull the retina away from the back of your eye. If the retina pulls away, a condition called detached retina, you may see floating spots or flashing lights. You may feel as if a curtain has been pulled over part of what you are looking at. A detached retina can cause vision loss or blindness if you don’t take care of it quickly. See an ophthalmologist—a doctor who diagnoses and treats all eye diseases—right away if you have these symptoms.
Some people with diabetic retinopathy also have a problem called macular edema. Macular edema, or swelling, can happen in any stage of retinopathy. Swelling in the macula is caused by leaking fluid from the retina’s damaged blood vessels.
Macular edema is the most common cause of vision loss for people with diabetes. Your vision loss can be mild to severe if the edema is not treated, so it is important to have an eye exam at least once a year. You can have an eye exam with an ophthalmologist or an optometrist—a primary eye care provider who prescribes glasses and contact lenses and diagnoses and treats certain conditions and diseases of the eye.
What are the symptoms of diabetes retina problems?
Often, no symptoms appear during the early stages of diabetes retina problems. As retina problems worsen, your symptoms might include
- blurry or double vision
- rings, flashing lights, or blank spots in your vision
- dark or floating spots in your vision
- pain or pressure in one or both of your eyes
- trouble seeing things out of the corners of your eyes
How can my eye doctor tell whether I have diabetes retina problems?
Your eye doctor can tell whether you have diabetes retina problems during a dilated eye exam. In a dilated eye exam, your eye doctor will use eye drops to enlarge your pupils. Your pupil is the opening at the center of the iris.
Enlarging your pupils allows your eye doctor to see more of the inside of your eyes to check for signs of disease. Your eye doctor will use a special magnifying lens to look at your retina and optic nerve for signs of damage and other eye problems.At the time of your dilated eye exam, your eye doctor also will conduct other tests to measure
- pressure in your eyes
- your side, or peripheral, vision
- how well you see at various distances
Have a dilated eye exam at least once a year, even if your vision seems fine. Regular exams can prevent most instances of severe vision loss or blindness from diabetes eye problems. These exams can also help you protect your vision and make sure you are seeing at your best.
You may need to see an ophthalmologist to have a test called an eye angiogram.
For this test, you will be given eye drops to dilate your pupils. You will be asked to place your chin on a camera’s chin rest and your forehead against a support bar to keep your head still during the test. Your ophthalmologist will take pictures of the insides of your eyes. A dye is injected into a vein in your arm. As the dye reaches your eyes and moves through your eyes’ blood vessels, the camera takes more pictures.
This test will show whether you have abnormal or leaking blood vessels on your retina and help your ophthalmologist decide the best treatment.
Will I have diabetes retina problems?
The longer you’ve had diabetes, the more likely you are to have diabetes retina problems. You are less likely to have diabetes retina problems, or will have milder problems if you have them, if you keep your blood glucose numbers close to your targets. Targets are numbers you aim for.
Does pregnancy affect diabetes retina problems?
Changes in your body during pregnancy might cause diabetes retina problems to occur or worsen.
If you have diabetes and are planning to get pregnant soon, you should have a dilated eye exam and talk with your eye doctor about diabetes retina problems. If you need surgery for your eyes, you may want to have it before you get pregnant.
If you have diabetes and are already pregnant, you should have a dilated eye exam during your first 3 months of pregnancy or as soon as possible. Talk with your eye doctor about how often you should have dilated eye exams throughout your pregnancy to keep your eyes healthy.
If you have gestational diabetes, a type of diabetes that develops only during pregnancy, you do not have an increased risk of getting diabetic retinopathy unless the diabetes continues after your pregnancy.
How are diabetes retina problems treated?
You can help your diabetes retina problems by controlling your
- blood glucose
- blood pressure
- cholesterol and triglycerides, or types of blood fat
If your retinopathy still does not improve, then you may need other treatments. You will need to see an ophthalmologist who can decide whether you need one of these treatments:
- Medicines. Your doctor treats macular edema with injections of medicines into the eye. These medicines block a protein in the body that causes abnormal blood vessel growth and fluid leakage. Reducing the fluid leakage often allows the retina to return to normal thickness. The ophthalmologist will numb your eye and then insert a tiny needle to deliver the medicine.
- Laser treatment. Your doctor can also treat macular edema with focal laser treatment. In one visit, the ophthalmologist will numb your eye and place many small laser burns in the areas leaking fluid near the macula. These burns slow the leakage of fluid and reduce the amount of fluid in your retina.
Sometimes your doctor also treats diabetic retinopathy with scatter laser treatment. In two or more visits, the ophthalmologist will numb your eye and place thousands of laser burns around the new, weak blood vessels away from the macula, causing them to shrink.
Laser treatment can greatly reduce your chances of blindness from retina damage. However, laser treatment often cannot restore vision that has already been lost.
Treatment with medicines or lasers can be performed in your ophthalmologist’s office.
- Vitrectomy. If the bleeding in your eye is severe, you may need to go to the hospital for a surgery called a vitrectomy. Your ophthalmologist will numb your eye or give you general anesthesia to help you fall asleep. The ophthalmologist will make a tiny cut in your eye and remove the vitreous gel that is clouded with blood. The ophthalmologist replaces the vitreous gel with a salt solution.
What other eye problems can occur in people with diabetes?
People with diabetes can have the following eye problems more often and at a younger age than people who do not have diabetes:
- Cataract. A cataract is a clouding of the normally clear lens that causes blurry vision. You need surgery to remove a cataract. During surgery, the ophthalmologist takes the lens out and puts in a plastic lens that is similar to a contact lens. The plastic lens stays in your eye permanently.
- Glaucoma. Glaucoma is a group of diseases that may be caused by an increase in eye pressure. Glaucoma can damage the optic nerve and result in vision loss and blindness. People with diabetes are more likely to get a severe type of glaucoma in which abnormal blood vessels grow in the front part of your eye. Your ophthalmologist will treat glaucoma with eye drops, pills, or surgery to control your eye pressure.
- Neuropathy. Neuropathy is nerve damage. Damage to the nerves in the feet or legs is the most common nerve damage from diabetes. However, diabetes can also affect the nerves to the eye. Having high blood glucose from diabetes causes decreased blood supply to the optic nerve. You may suddenly have double vision, drooping of your eyelid, or pain over your eye. Some people have full or partial paralysis of their eye muscles. This type of neuropathy tends to improve by itself over a period of weeks to months. If it doesn’t, you may need to wear a patch over one eye or use a special lens to try to align your eyes.
How does smoking affect diabetes eye problems?
Like diabetes, smoking damages the tiny blood vessels in your eyes. Smoking is also linked to an increase in pressure inside your eye that can lead to glaucoma and optic nerve damage.
Smoking and diabetes are a dangerous mix. Smoking raises your risk for many diabetes problems. If you quit smoking,
- you will lower your risk for heart attack, stroke, nerve disease, kidney disease, and amputation, which is surgery to cut off a body part
- your cholesterol and blood pressure levels might improve
- your blood circulation will improve
If you smoke, stop smoking. Ask for help so that you don’t have to do it alone. You can start by calling 1–800–QUITNOW (1–800–784–8669).
What can I do if I already have some vision loss from diabetes retina problems?
If you already have some vision loss from diabetes retina problems that cannot be corrected by treatment, ask your eye doctor about low vision services and devices that can help you make the most of your remaining vision. Ask for a referral to a specialist in low vision. Many community organizations and agencies offer information about low vision counseling and training, and other special services for people with vision problems.
How can I keep my eyes healthy?
You can keep your eyes healthy by taking these steps:
- Keep your blood glucose numbers as close to your targets as you can. Improving your blood glucose numbers can greatly lower your risk for retinopathy. Your doctor will work with you to set your target blood glucose numbers and teach you what to do if your numbers are too high or too low.
- Keep your blood pressure as close to your target as you can. High blood pressure can damage the tiny blood vessels on the retina. Have your blood pressure checked at every medical visit. Ask your doctor whether you need medicine or a combination of medicines to control your blood pressure. If your doctor prescribes blood pressure medicine, take it regularly.
- Have a healthy diet and be physically active to reduce your need for medicines to control your blood glucose, blood pressure, cholesterol, and triglycerides.
- Diabetes Diet and Eating
- Physical Activity and Diabetes
More information is provided in the NIDDK health topics:
- If you smoke, stop smoking.
- Call your eye doctor right away if you have any signs of eye problems, especially sudden vision loss.
- Have a dilated eye exam at least once a year, even if your vision seems fine.
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