Macular Degeneration (AMD)

Macular degeneration is a disease of the central retina (called the macula) that affects central vision. It is the leading cause of vision loss among people over age 65.

Because it affects only central vision, macular degeneration does not cause total blindness. But it can make most daily activities like driving and reading difficult or impossible.

What causes it?

The exact cause of macular degeneration is still not understood, but it is thought to be associated with atherosclerotic changes in the tiny blood vessels that nourish the macula, compromising the blood flow to this part of the retina.

Age clearly plays a role in the disease. For this reason, it is often referred to as age-related macular degeneration (AMD).

Macular degeneration has two forms

There are two forms of AMD:

• Dry AMD is the more common form, affecting approximately 90 percent of those who have macular degeneration. It typically develops slowly and causes mild visual distortion to moderate central vision loss.
• Wet AMD affects only 10 percent of people with macular degeneration, but causes more severe vision loss. In wet AMD, new blood vessels that form under the macula leak fluid and can cause a rapid and severe loss of central vision.

How common is AMD?

Macular degeneration is the most common cause of severe vision loss among individuals over age 65. It's estimated that over 11 million people in the United States have AMD. It affects about 9 percent of the population over age 40, and causes vision loss of 20/200 or worse (legal blindness) in 15 to 20 percent of those with the condition.

Age is the greatest risk factor. People in their forties have only about a two percent. Those over age 75 have a 30 percent risk.

Other risk factors include:

• Smoking
• A family history of AMD
• High cholesterol
• A poor ability to tan when young
• Excessive exposure to sunlight
• High dietary intake of saturated fat and cholesterol
• Uncontrolled hypertension
• A high body mass index in men
• Race - AMD affects Caucasians more frequently than people of other races
• Gender - Women are twice as likely to develop AMD

What are the symptoms of AMD?

Macular degeneration is painless. Visual symptoms are constant and limited to the central area of a person's visual field. They include:

• Distorted vision
• Blurred vision
• A central darkened spot or empty area

Can macular degeneration be treated?

Though there is currently no widely accepted treatment for macular degeneration, promising new medications are currently being developed. If you or a family member has AMD, ask your eye doctor about new treatment options that may be available.

Can macular degeneration be prevented?

Recent research suggests certain antioxidant vitamins and other nutritional supplements may slow or prevent the development of macular degeneration in some individuals. Vitamins A, C and E; zinc; Carotenoids; and lutein may be beneficial in maintaining a healthy retina. (These substances, however, have not been shown to reverse existing damage to the retina from AMD.)

Actions you can take to lower your risk of AMD include:

• Get plenty of exercise
• Maintain a proper weight
• Eat a healthy diet
• Avoiding smoking
• Take a multiple antioxidant vitamin supplement daily

Because excessive exposure to sunlight is a risk factor for AMD, it's also a good idea to wear sunglasses outdoors that provide 100 percent UV protection. A wide-brimmed hat also helps limit the amount of UV radiation reaching your eyes.

Low vision aids

People who have lost vision due to AMD can often benefit from low vision aids. These specialized optical devices provide high magnification and help a person with AMD use their remaining central vision as effectively as possible.