December 14, 2016

Macular degeneration is common in people older than 55, but lifestyle influences who gets it.


Macular degeneration is the top cause of vision loss in people older than 55. It affects more than 10 million people in the United States. Macular degeneration involves losing the ability to see in the center of your field of vision. Janice Law., M.D., an ophthalmologist and retina specialist with the Vanderbilt Eye Institute, explains this common condition, and a powerful way to prevent it.


What is macular degeneration?

This condition happens when cellular waste builds up in the center area of the retina, called the macula. The retina is specialized, neural tissue lining the inner wall of the eye. The macular region is responsible for our central vision, or what we see when we focus in the center of our field of vision. The macula is also responsible for our sharpest vision and our color vision.


What causes it?

High-tech imaging lets doctors see layered views of the retina. A hallmark of macular degeneration that they look for, Law said, is yellowish spots in the retina, called drusen, which are fatty proteins, the buildups of cellular waste that the eye hasn’t cleared out. Scientists don’t know whether drusen is created because the cells in the retina are sloughing off too much waste material, or whether the eye’s natural process to clear this waste is no longer working adequately.


What are the signs?

Macular degeneration means the deterioration or loss of vision in the middle of your field of vision. It can appear as a gray, dark, fuzzy or distorted spot in the middle of your view, while your peripheral vision remains clear.

Over time, as the condition worsens, that spot of blurry vision or no vision in the middle of your view gets darker or larger. Also, some people have trouble perceiving the contrast between colors – so they may not be able to see objects’ shadows, Law said, or distinguish between the colors of a traffic light.


What are the risk factors?

Age is a big risk factor; the older you get, the greater your risk for developing this problem.

Other risk factors are ethnicity (Caucasians are at greatest risk), genetics and smoking.

The latter is important, because it’s something people can control. Law urges smokers to quit this habit to reduce their risk of developing macular degeneration in their later years.


What are the two types of macular degeneration?

The most common type, affecting 80 percent of people with this condition, is “dry” macular degeneration.

With this type, lost vision cannot be restored. Currently there is no treatment for it. People can slow the progression of dry macular degeneration with lifestyle changes: sunglasses for UV protection, healthy eating including leafy green vegetables and fish, and quitting smoking, Law says. Over-the-counter AREDS (age-related eye disease study) vitamins can reduce the risk of age-related macular degeneration and help slow the progression of the disease.

The second type is wet, or “bleeding.” If it’s left untreated, the retina becomes scarred and vision loss cannot be reversed.

However, there is treatment for this type, Law said. Medication injected into the eye can stop the bleeding, stabilize the disease and possibly restore some vision. There’s also a new drug being studied, she said, that may reduce the number of injections needed to control the disease.

Scientists don’t fully understand why someone develops one type instead of the other. Both types get worse over time, but people with this condition don’t experience vision loss at the same rate. Some people’s condition may worsen slowly over time, and others’ deteriorates more rapidly.

“Smoking does play a huge role” in speeding the progression of the disease, Law says.

To check your eyes for signs of macular degeneration or other common vision problems affecting people as they age, get an eye exam every year after turning 50.


Are your eyes in need of care? The Vanderbilt Eye Institute assesses and treats a variety of conditions. Call 615-936-2020 for an appointment.

Janice C. Law, M.D., is assistant professor of vitreoretinal surgery and diseases and director of medical student education at Vanderbilt Eye Institute. She is chair of the American Academy of Ophthalmology’s Young Ophthalmologists committee, serving 7,000 domestic and international young ophthalmologists. Her research is focused on curriculum development and skills assessment in ophthalmology.