It's possible to have diabetic retinopathy and not know it. In fact, it's uncommon to 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
- Dark or empty areas in your vision
- Vision loss
- Difficulty with color perception
Diabetic retinopathy usually affects both eyes.
Diabetic retinopathy may be classified as early or advanced, depending on your signs and symptoms.
- Early diabetic retinopathy. This type of diabetic retinopathy is called nonproliferative diabetic retinopathy (NPDR). It's called that because at this point, new blood vessels aren't growing (proliferating). NPDR can be described as mild, moderate or severe. When you have NPDR, the walls of the blood vessels in your retina weaken. Tiny bulges (called microaneurysms) protrude from the vessel walls, sometimes leaking or oozing fluid and blood into the retina. As the condition progresses, the smaller vessels may close and the larger retinal vessels may begin to dilate and become irregular in diameter. Nerve fibers in the retina may begin to swell. Sometimes the central part of the retina (macula) begins to swell, too. This is known as macular edema.
- Advanced diabetic retinopathy. Proliferative diabetic retinopathy (PDR) is the most severe type of diabetic retinopathy. It's called proliferative because at this stage, new blood vessels begin to grow in the retina. These new blood vessels are abnormal. They may grow or 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, causing glaucoma. This can damage the nerve that carries images from your eye to your brain (optic nerve).
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 dilated eye exam — even if your vision seems fine — because it's important to detect diabetic retinopathy in the early stages. If you become pregnant, your eye doctor may recommend additional eye exams throughout your pregnancy, because pregnancy can sometimes worsen diabetic retinopathy.
Contact your eye doctor right away if you experience sudden vision changes or your vision becomes blurry, spotty or hazy.
Too much sugar in your blood can damage the tiny blood vessels that nourish the retina. It may even block them completely. As more and more blood vessels become blocked, the blood supply to more of the retina is cutoff. This can result in vision loss. In response to the lack of blood supply, the eye attempts to grow new blood vessels. But, these new blood vessels don't develop properly and can leak easily. Leaking blood vessels can cause a loss of vision. Scar tissue may also form, which can pull on the retina. Sometimes, this can cause the retina to detach.
Elevated blood sugar levels can also affect the eyes' lenses. With high levels of sugar over long periods of time, the lenses can swell, providing another cause of blurred vision.
Diabetic retinopathy can happen to anyone who has diabetes. These factors can increase your risk:
- Duration of diabetes — the longer you have diabetes, the greater your risk of diabetic retinopathy
- Poor control of your blood sugar level
- High blood pressure
- High cholesterol
- Tobacco use
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 or 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.
If you have diabetes, reduce your risk of getting diabetic retinopathy by doing the following:
- Make a commitment to managing 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. Careful monitoring is the only way to make sure that your blood sugar level remains within your target range. 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. If you've been meeting your blood sugar goals, your doctor will likely perform this test twice a year. But, if your A1C is higher than your goal, more frequent testing is recommended. Remember, keeping your blood sugar level as close to normal as possible slows the progression of diabetic retinopathy and reduces the need for surgery.
- Keep your blood pressure and cholesterol under control. High blood pressure and high cholesterol increase the risk of vision loss. 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. Talk to your doctor about ways to stop smoking or to stop using other types of tobacco.
- Pay attention to vision changes. Yearly dilated eye exams are an important part of your diabetes treatment plan. 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 poor vision. Taking an active role in diabetes management can go a long way toward preventing complications.