Diabetic Retinopathy

Diabetic retinopathy (die-uh-BET-ik ret-ih-NOP-uh-thee) is a complication of diabetes that affects the eyes. It's caused by damage to the blood vessels of the light-sensitive tissue at the back of the eye (retina).

At first, diabetic retinopathy may cause no symptoms or only mild vision problems. Eventually, however, diabetic retinopathy can result in blindness.

Diabetic retinopathy can develop in anyone who has type 1 diabetes or type 2 diabetes. The longer you have diabetes, and the less controlled your blood sugar is, the more likely you are to develop diabetic retinopathy.

To protect your vision, take prevention seriously. Start by carefully controlling your blood sugar level and scheduling yearly eye exams.

Symptoms

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).

Causes

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.

Risk factors

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
• Pregnancy
• Tobacco use

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.