What is diabetic retinopathy?
Diabetic retinopathy is an eye disease caused by diabetes, and it is a leading cause of vision loss in working-age adults. Over time, high blood sugar damages the tiny blood vessels in the retina, the light-sensing layer at the back of the eye. Damaged vessels can leak fluid or blood, and the retina can be starved of the oxygen it needs.
The earlier stages usually cause no symptoms, so many people do not know they have it. The good news is that with regular eye exams, good diabetes control and today’s treatments, most serious vision loss from diabetes can be prevented.
The stages of diabetic retinopathy
- Non-proliferative diabetic retinopathy (NPDR) is the earlier stage. Blood vessel walls weaken, bulge and may leak small amounts of blood or fluid into the retina. It is graded as mild, moderate or severe. Mild NPDR often stays stable for years, but the more advanced it becomes, the higher the chance it will progress.
- Proliferative diabetic retinopathy (PDR) is the advanced stage. When parts of the retina are not getting enough blood, the eye grows new, abnormal blood vessels. These fragile vessels can bleed into the gel inside the eye, causing floaters or sudden loss of vision, and they can form scar tissue that pulls on the retina and causes a retinal detachment. PDR can also lead to a severe type of glaucoma.
Diabetic macular edema
At any stage, fluid can leak into the macula, the center of the retina that gives you sharp, detailed vision. This swelling is called diabetic macular edema (DME), and it is the most common reason people with diabetes lose vision. It usually makes central vision blurry or wavy.
Who is at risk?
Anyone with type 1 or type 2 diabetes can develop diabetic retinopathy. Your risk is higher if you:
- Have had diabetes for many years
- Have blood sugar that is often high (a high A1C)
- Have high blood pressure or high cholesterol
- Smoke
- Have kidney disease
- Are pregnant
Pregnancy can make diabetic retinopathy progress faster. Women with type 1 or type 2 diabetes should have a dilated eye exam before or early in pregnancy, and follow-up exams as their eye doctor recommends.
What are the symptoms?
In the early stages there are usually no symptoms at all: no pain, no redness and no change in vision. As the disease advances, you may notice:
- Blurry vision, or vision that changes from day to day
- New spots or dark strings floating in your vision (floaters)
- Dark or empty areas in your vision
- Trouble seeing colors
A sudden shower of floaters, a curtain over your vision or a sudden loss of vision needs to be checked right away.
How is it diagnosed?
A dilated eye exam lets your doctor see the retina and its blood vessels clearly. A painless scan called OCT (optical coherence tomography) shows whether there is swelling in the macula. In some cases, retinal photographs or a dye test called fluorescein angiography are used to see which vessels are leaking or closed off.
How is diabetic retinopathy treated?
For every stage, the foundation of treatment is controlling blood sugar, blood pressure and cholesterol with your primary care doctor. Good control lowers the chance that retinopathy will start or get worse.
- Mild to moderate NPDR without swelling: usually no eye treatment is needed. Your eyes are monitored with regular exams to catch any change early.
- Diabetic macular edema: the main treatment is anti-VEGF medicine, given as a quick injection into the eye after it is fully numbed. These medicines reduce leakage and swelling, and many patients see their vision improve. Injections are usually repeated on a schedule, and steroid medicines are sometimes used as well.
- Proliferative diabetic retinopathy: any swelling in the macula is treated first with anti-VEGF injections. Once the swelling has resolved, a LASER treatment called panretinal photocoagulation (PRP) is applied to the outer retina to shrink the abnormal blood vessels and lower the risk of bleeding and detachment. Anti-VEGF injections can also help control the abnormal vessels.
- Advanced complications: if bleeding inside the eye does not clear, or scar tissue pulls the retina loose, a surgery called vitrectomy may be needed to remove the blood or scar tissue.
Protecting your vision
- Have a dilated eye exam at least once a year, even if your vision seems fine
- Keep your A1C, blood pressure and cholesterol in your target range
- Don’t smoke
- Call promptly if your vision changes
Most vision loss from diabetes can be prevented when diabetic retinopathy is found early. If you have diabetes, schedule a diabetic eye exam every year.