The American Academy of Ophthalmology recognizes the month of February to promote awareness about Age-related Macular Degeneration, also called simply macular degeneration or AMD, the nation’s leading cause of vision loss. We at the UW Department of Ophthalmology and Visual Sciences want to inform you, our patients and families, about the disease, what to look for if you think you might have AMD and offer insights into how to prevent or stop the progression of macular degeneration, as well as ways to cope with low vision.
Here are the facts about AGE-RELATED MACULAR DEGENERATION:
SOURCE: National Eye Institute, American Academy of Ophthalmology, American Macular Degeneration Foundation.
AMD is a deterioration of the eye’s macula, the central part of the light-sensitive tissue at the back of the eye called the retina. The macula is much more light sensitive than the rest of the retina and helps us focus in fine detail, such as the ability to recognize faces, read fine print, read street signs, etc. As the macula is only a small part of the retina, its degeneration does not usually affect your peripheral vision, which is not as fine and detailed as your central vision.
In AMD, as the macular tissue ages, it tends to thin out. Tiny pieces of a fatty protein called drusen start to accumulate under the retina. At some point the macula stops functioning properly and the light signals the retina sends to the brain via the optic nerve become distorted and central vision starts to worsen and may eventually disappear.
There are two forms of AMD, “dry” and “wet.” The majority of people with macular degeneration have the dry form. With dry AMD, vision loss usually happens more slowly. When dry AMD is diagnosed in early stages your ophthalmologist will see a build-up of medium-sized drusen behind your retina. As the disease progresses and your central vision diminishes, the drusen become larger and there may also be pigment changes in your retina. In late dry AMD the actual light-sensing cells start to break down so they can no longer convey the visual information to the brain. When you are diagnosed with dry AMD, it will be very important to keep a regular appointment with your ophthalmologist because dry AMD can change into the more damaging form called wet macular degeneration. Wet AMD is diagnosed when the doctor sees the growth of abnormal blood vessels underneath the retina. These blood vessels may leak fluid and blood, further distorting your vision. This process can happen faster and cause more noticeable changes than the dry form.
The American Academy of Ophthalmology lists the following symptoms for both dry and wet AMD:
One or both eyes can be affected. Often times vision loss in one eye is masked because the other eye compensates, making vision loss virtually unnoticeable.
Symptoms of wet AMD typically appear and progress more quickly.
The National Eye Institute emphasizes that early and intermediate stages of AMD usually start with no symptoms. The only way to detect AMD is to have a comprehensive eye exam, which may include one of the following:
During your exam, your doctor will be looking for evidence of drusen deposits underneath your retina. The presence of larger deposits is indicative of AMD. You doctor will also be looking for possible changes in your eye pigment underneath your retina with development of areas of dark pigment clumping and other areas of loss of pigment. This is another possible sign of AMD.
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