Macular Degeneration

What is age-related macular degeneration (AMD)?

AMD is an eye disease that can gradually diminish sharp, central vision. Our central vision is what we use to see objects clearly, and our clearest vision comes from the central part of the retina called the macula. In some people, AMD advances so slowly that it will have little effect on their vision as they age. But in others, the disease progresses faster and may lead to difficulty doing normal tasks of daily living, such as reading normal size print or driving.

How does AMD damage vision?

The retina is a paper-thin tissue that lines the back of the eye and sends visual signals to the brain. In the middle of the retina is a tiny area called the macula. The macula is made up of millions of light-sensing cells, called photoreceptors, that help to produce central vision.

AMD occurs in two forms:

Dry AMD--Ninety percent of all people with AMD have this form. Research has found that the majority of AMD has a genetic basis. For some reason, the bottom layer of the retina, known as the retinal pigment epithelium or RPE, starts to loose it's ability to thrive. When this pigment layer of the retina stops to function, the light-sensing cells in the macula stop working, leading to blurry or missing central vision.
Wet AMD--Although only 10 percent of all people with AMD have this type, it accounts for 90 percent of all blindness from the disease. As dry AMD worsens, new blood vessels may begin to grow, leak, and cause what's called "wet" AMD. Because these new blood vessels tend to be very fragile, they will often leak blood and clear fluid under the macula, causing macular edema or swelling. Without treatment, this swelling can cause further loss of vision.

Who is most likely to get AMD?

The greatest risk factor is age and having a genetic predisposition. Although AMD may occur during our 40's and 50's, studies show that people over age 60 are clearly at greater risk than other age groups. For instance, a large study found that people in middle-age have about a 2 percent risk of getting AMD, but this risk increased to nearly 30 percent in those over age 75. Early detection by having annual eye exams is recommended for anyone over the age of 40 with a family history of macular degeneration.

Other AMD risk factors include:

Gender - Women tend to be at greater risk for AMD than men.
Race - Caucasians are much more likely to lose vision from AMD than African Americans.
Smoking -Smoking increases the risk of AMD.
Lifestyle - Eating vitamin-deficient processed foods and being overweight directly affect a persons cardiovascular health which can in turn affect the quality of blood supply and nutrients to the eyes.

What are the symptoms?

Both dry and wet AMD are painless! The most common early sign of dry AMD is blurred vision. As fewer cells in the macula are able to function, people will see details less clearly in front of them, such as faces or words in a book. Often this blurred vision will go away in brighter light. If the loss of these light-sensing cells becomes great, people may see a small-but growing-blind spot in the middle of their field of vision.

The classic early symptom of wet AMD is that straight lines appear crooked. This results when fluid from the leaking blood vessels gathers and lifts the macula, distorting vision. A small blind spot may also appear in wet AMD, resulting in loss of one's central vision.

How is it detected?

Your eye doctor will be checking for AMD at your yearly eye exam. If you are over 60 and have had recent changes in your central vision, you will need to be seen sooner. Call your eye doctor immediately if you have any new blurry vision. To look for signs of the disease, your doctor will use eye drops to dilate, or enlarge, your pupils. Dilating the pupils allows your eye care professional to view the back of the eye better.

You may also be asked to view an Amsler grid, a pattern that looks like a checkerboard. Early changes in your central vision will cause the grid to appear distorted, a sign of AMD.

How can it be treated?

There are no current surgical or medical treatments for dry AMD. Hundreds of studies have suggested or proven that eating certain foods, taking dietary supplements, and leading a heart-healthy lifestyle may slow the progress of the disease. Some studies have even shown results of reversal some of the signs and symptoms of macular degeneration. Talk to your optometrist or ophthalmologist about their recommendations for the best ways that you can prevent or slow down macular degeneration in your eyes.

Retinal eye surgeons and other trained ophthalmologists can treat wet AMD with a medication that's injected into the eye. Because these medications, such as Avastin and Lucentis, are short acting, re-treatment is usually needed every 4 to 6 weeks. Newer injectable medications are being studied that may last longer. An older less frequently used treatment called PDT involves aiming a strong light beam onto the leaky blood vessels to destroy them.

What research is being done?

The National Eye Institute is funding a number of research studies to learn what causes AMD and how it can be better treated. For instance, in the Age-Related Eye Diseases Study (AREDS), researchers are assessing the aging process in the eyes of thousands of older people to discover the earliest signs of AMD. The same study is also evaluating the effects of certain vitamins and minerals in preventing or slowing the progress of AMD. Those results are expected to be released soon.

At the same time, other scientists are trying to learn more about how the cells in the retina work. This knowledge will allow them some day to pinpoint the cause of the disease and design methods to prevent it.

What can you do to protect your vision?

Have your eyes examined yearly by an optometrist or ophthalmologist.
Follow a heart-healthy lifestyle, remember if it's good for your heart it's good for your eyes!
Protect your eyes with 100% UV light filters, especially UVA and UVB radiation.
Ask your eye doctor which, if any, dietary supplements would be beneficial for your eyes.