If You Have Diabetes, Get a Comprehensive Dilated Eye Exam

People with diabetes should have a comprehensive dilated eye exam at least once a year to check for early signs of diabetic retinopathy, a leading cause of visual impairment. Timely treatment and appropriate follow up care can reduce the risk of blindness by 90 percent, even for people with advanced diabetic retinopathy.

Why do people with diabetes need comprehensive dilated eye exams?

The early stages of diabetic retinopathy often have no warning signs. People with the disease can go years without ever knowing they have it.
In fact, between 40 and 45 percent of people with diagnosed diabetes have some form of the disease. The longer you have diabetes, the more likely you are to develop diabetic retinopathy. A comprehensive dilated eye exam allows your eye care professional to look for signs of eye disease by examining your retina, the light­ sensitive tissue at the back of your eyes. In people with diabetic retinopathy, leaking blood vessels can cause vision loss.

What are the symptoms?

At first, people may notice no symptoms, warning signs, or changes to their vision. However, diabetic retinopathy can get worse over time and cause vision loss. Floaters can be a sign of diabetic retinopathy. Sometimes difficulty reading or doing close work can indicate that fluid is collecting in the macula, the most light­sensitive part of the retina. This fluid build­up is called macular edema. Another sign is double vision, which occurs when the nerves controlling the eye muscles are affected. If you experience any of these signs, see your eye doctor immediately. Otherwise, diabetics should see their eye doctor at least once a year for a dilated eye exam.

How does diabetic retinopathy cause vision loss?

Blood vessels damaged from diabetic retinopathy can cause vision loss in two ways:
Fragile, abnormal blood vessels can develop and leak blood into the center of the eye, blurring vision.
Fluid can leak into the center of the macula, the part of the eye where sharp, straight-ahead vision occurs. The fluid makes the macula swell, blurring vision. Diabetic retinopathy usually affects both eyes.

How is diabetic retinopathy detected?

A comprehensive dilated eye exam allows your eye care professional to look for signs of eye disease by examining your retina, the light­ sensitive tissue at the back of your eyes. Your eye doctor may diagnose retinopathy using a special test called fluorescein angiography. In this test, dye is injected into the body and then gradually appears within the retina due to blood flow. Your eye care practitioner will photograph the retina with the illuminated dye. Evaluating these pictures tells your doctor how far the disease has progressed.

What are the stages of diabetic retinopathy?

Diabetic retinopathy has four stages:

1. Mild Non-proliferative Retinopathy – At this earliest stage, micro aneurysms occur. They are small areas of balloon­-like swelling in the retina’s tiny blood vessels.
2. Moderate Non-proliferative Retinopathy – As the disease progresses, some blood vessels that nourish the retina are blocked.
3. Severe Non-proliferative Retinopathy – Many more blood vessels are blocked, depriving several areas of the retina with their blood supply. These areas of the retina send signals to the body to grow new blood vessels for nourishment.
4. Proliferative Retinopathy – At this advanced stage, the signals sent by the retina for nourishment trigger the growth of new blood vessels. This condition is called proliferative retinopathy. These new blood vessels are abnormal and fragile. They grow along the retina and along the surface of the clear, vitreous gel that fills the inside of the eye. By themselves, these blood vessels do not cause symptoms or vision loss. However, they have thin, fragile walls. If they leak blood, severe vision loss and even blindness can result.

Can diabetic retinopathy be treated?

Yes. If diabetic retinopathy is diagnosed and treated early, additional vision loss can be avoided. However, vision already lost cannot be restored. Leaking blood vessels can be repaired and extra blood vessels can be removed. Your ophthalmologist may suggest laser surgery. He or she places several laser burns in the areas of the retina away from the macula, causing the abnormal blood vessels to shrink. Scatter laser treatment may be able to save the rest of a person’s sight.

How can you protect your vision?

The best protection is to get a comprehensive dilated eye exam at least once a year. If you have diabetic retinopathy, you may need an eye exam more often. People with proliferative retinopathy can reduce their risk of blindness by 95 percent with timely treatment and appropriate follow­up care.
The Diabetes Control and Complications Trial (DCCT) showed that better control of blood sugar levels slows the onset and progression of retinopathy. The people with diabetes who kept their blood sugar levels as close to normal as possible also had much less kidney and nerve disease. Better control also reduces the need for sight­saving laser surgery.
This level of blood sugar control may not be best for everyone, including some elderly patients, children under age 13, or people with heart disease. Be sure to ask your doctor if such a control program is right for you.