What Is Macular Degeneration? What to Know About This Sight-Robbing Eye Condition

Age-related macular degeneration is a leading cause of blindness. Learn how to recognize it before you even have symptoms.

What is macular degeneration?

Age-related macular degeneration (AMD) is a progressive eye disease primarily affecting your central vision, making it difficult to cook, read, drive, and recognize people.

“It’s a leading cause of blindness in the United States and in the world,” says Emily Y. Chew, MD, the director of the division of epidemiology and clinical applications at the National Eye Institute. “The older you are, the more likely you are to get it.”

Learn about the two types of macular degeneration and how you can recognize it before it’s too late.

Types of macular degeneration

As many as 90 percent of people with macular degeneration have what’s called dry macular degeneration or atrophic macular degeneration.

“Over the course of a lifetime, the byproducts of vision build up underneath the retina and form deposits called drusen,” explains Jacque Duncan, MD, a professor of clinical ophthalmology and academic director of the Retina Service at the University of California San Francisco.

This leads to thinning of the macula at the center of the retina and, eventually, vision loss.

Many fewer people have wet or advanced neovascular AMD, but they can lose their vision quickly when they do.

“This is when new blood vessels grow underneath the retina,” Dr. Duncan says. “It causes swelling and leaking and bleeding.”

This least common form of AMD is responsible for some 90 percent of severe vision loss from AMD. “The wet form really takes its toll on vision,” says Abdhish R. Bhavsar, MD, a clinical spokesperson for the American Academy of Ophthalmology.

(Read about 20 simple habits to improve your vision.)

Senior woman having vision problems while looking at smartphonedemaerre/Getty Images

Risk factors for macular degeneration

No one knows exactly what causes macular degeneration, but older age and family history are the two main risk factors. Another is smoking, which doubles your chances of developing the condition. “In every study, the more you smoke, the higher the risk,” Dr. Chew says.

Macular degeneration also shares many risk factors with heart disease, including high blood pressure and cholesterol; a diet rich in meat, butter, and other saturated fats; and lack of exercise.

Being Caucasian and overexposure to ultraviolet (UV) light can contribute to risk as well.

(Here are 10 foods that slash your risk of macular degeneration.)

Symptoms of macular degeneration

Macular degeneration is a progressive disorder with three stages—early, middle, and late—that unfold over the years. Typically there are no symptoms in the early stages, and symptoms (like mild blurriness) that may go unnoticed in the intermediate stage.

“In early disease, most people don’t even know they have it for years and years and years,” says Dr. Bhavsar, who is also director of the Retina Center in Minneapolis. “The main change in the advanced form is distortion—crookedness or waviness—in your vision.”

While you may maintain your peripheral (side) vision, you’ll experience blank spots in your central vision and have trouble making out details and seeing in the dark.

Vitamins for dry macular degeneration

There’s no medical treatment for dry AMD, but two large studies sponsored by the National Eye Institute have found that a specific combination of vitamins and minerals can reduce the risk of vision loss by about 25 percent, Dr. Chew says.

The formula (named AREDS, after the trial) is available over the counter under different brand names, including PreserVision. It won’t help prevent AMD, but it can slow the progression from intermediate to late-stage disease.

“It’s easy to take, and most of the formulations are two pills a day,” Dr. Bhavsar says. “It’s in drugstores and doctors’ offices.”

Make sure the bottle you buy specifically says “AREDS” and contains vitamins C and E, lutein, zeaxanthin, zinc, and copper. An earlier version of AREDS contained beta carotene, but this was found to increase the risk of lung cancer in smokers. Most formulations available today do not contain beta carotene.

Treatments for wet macular degeneration

Unlike dry AMD, wet AMD does have treatments. One is photodynamic therapy (PDT), which uses a combination of an injected medicine and laser light to stunt the abnormal blood vessels.

Anti-VEGF drugs also treat wet AMD by blunting the growth of abnormal blood vessels in your eye. Several of these drugs are available, including Avastin, originally developed for treating colorectal and other forms of cancer.

(Learn how to protect your eyesight.)

Screening and diagnosing AMD

Mature women at a medical appointment with ophthalmologist doctorFG Trade/Getty Images

The most important thing you can do for the health of aging eyes is to let your doctor check them regularly. The American Academy of Ophthalmology recommends comprehensive eye exams starting at age 40.

Not only will these exams, which should include dilation, be able to detect AMD, but they’ll also look for glaucoma and cataracts, two other eye conditions that are more common as we age.

One tool doctors use (and you can also use at home) is an Amsler grid. As its name suggests, it is a grid of horizontal and vertical lines, though you can also use any straight lines as a substitute.

Look at the grid every day using one eye at a time from about a foot away. If any of the lines look dim, wavy, bent, or blurry, contact your doctor. This could signal AMD.

“I recommend patients use the grid to help them discover distortion or anything missing in the vision field,” Dr. Bhavsar says.

Preventing AMD

“Pretty much everything that you can think of that can be healthy for your heart turns out to be good for your retina also,” Dr. Bhavsar says.

In other words, make sure you get plenty of exercise and eat fruits and vegetables with colors in them (they’re high in antioxidants). Wearing sunglasses that block ultraviolet rays can also help, he advises and if you smoke, quit.

Finally, keep up with regular eye exams.

Sources

Amanda Gardner
Amanda Gardner is a freelance health reporter whose stories have appeared in cnn.com, health.com, cnn.com, WebMD, HealthDay, Self Magazine, the New York Daily News, Teachers & Writers Magazine, the Foreign Service Journal, AmeriQuests (Vanderbilt University) and others. In 2009, she served as writer-in-residence at the University of Wisconsin School of Medicine and Public Health. She is also a community artist and recipient or partner in five National Endowment for the Arts grants.