More than 10 million Americans suffer the potentially disabling effects of macular degeneration, an eye disease that is the top cause of vision loss in people over age 55.
The incurable condition, which blurs central vision, is also called age-related macular degeneration (AMD) because it is associated with growing older, according to the National Eye Institute (NEI). Central vision is needed for driving, reading and recognizing faces and colors, among other tasks.
The macula is located in the center of the retina, the inside back layer of the eyeball that converts light and images into electrical signals that are sent to the brain. AMD can occur in one or both eyes.
AMD typically develops gradually and isn't painful, so early symptoms can be mistaken for normal age-related vision changes. According to the Mayo Clinic, symptoms include:
Causes & Complications
The exact causes of AMD aren't known, but certain physical conditions and lifestyle choices increase the odds of developing it. According to the NEI, these risk factors include:
There are two types of AMD: wet and dry.
Wet AMD is relatively rare, comprising only about 15 percent of all cases, according to the NEI. It is also more serious than dry AMD, and can trigger rapid vision loss. It develops when abnormal blood vessels behind the retina begin emerging under the macula, and leaking blood and fluid.
Dry AMD occurs when light-sensitive cells in the macula gradually deteriorate. The size and number of yellow deposits behind the retina called drusen, which dislodge the macula from its usual spot, often indicate how severe dry AMD has become. When drusen are numerous or large, dry AMD is usually more advanced, according to the NEI.
EMBED THIS GRAPHIC ON YOUR SITE
Diagnosis & Tests
AMD is suspected in people over 60 who experience recent changes in the center of their field of vision. Several tests can help confirm the diagnosis, including:
Treatments & Medication
While nothing cures AMD, various treatments are available depending on its type.
The progression of dry AMD from intermediate to advanced may be slowed by taking a daily high-dose combination of antioxidant vitamins and zinc, according to the NEI. The formulation includes:
Wet AMD has three main treatments, not all of which are appropriate for every patient. They include:
Several lifestyle changes can help AMD patients cope better with resulting vision loss, according to the Mayo Clinic. These include using magnifying lenses and glasses; adjusting computer font size and brightness level; using adaptive appliances such as clocks and telephones with extra-large numbers; and brightening room light levels.