What is Macular Degeneration? 

Age-related macular degeneration ( AMD) is the most common cause of irreversible vision loss in Americans over the age of 60. It is estimated that 10 million Americans will experience this age-related visual impairment during their retirement years.

Macular degeneration is a disorder of the retina, the light-sensitive inner lining of the eye. The macula is a small, central portion of the retina which is necessary for sharp, " Straight ahead" vision needed for reading, driving a car or recognizing faces.

There are a number of abnormalities associated with the term "age-related macular degeneration." They range from mild changes within decrease in vision to abnormalities severe enough to result in the loss of all "straight ahead" vision. Macular degeneration does not cause total blindness because the remaining and undamaged parts of the retina around the macula continue to provide "side" vision. There are two main types of macular degeneration. "dry" and "wet", which are discussed in the next section.
   

Signs and Symptoms

 Aging causes the cells in the retina to become less efficient. Ultimately, deposits called drusen appear under the retina and can be seen during an eye examination and on photographs of the retina. A few small drusen develop, vision may be decreased. Vision may be affected when there are pigment disturbances in the layer of cells called the retinal pigment epithelium. These two types of changes in the most common form. currently, there is no known treatment for dry AMD.

A few people experience the "wet" form of macular degeneration which can cause more serve visual loss. In this situation, abnormal blood vessels grow beneath the retina and result in bleeding and leakage of fluid. Vision may suddenly become distorted or blurred. In some cases of wet macular degeneration, laser treatment can be affective at destroying the abnormal vessels, thus preventing or slowing further visual loss. Wet macular degeneration cannot always be treated successfully by laser, however, some experimental drugs surgical procedures are being tested.

A self test

The Amsler Grid ( see figure below ) is used to screen for macular degeneration. In an effort to detect loss of vision associated with macular degeneration, eye doctors across the country are recommending this test to their patients. The test involves looking at a square grid with a dot in the center. The grid should be held 12 inches away from the face. While wearing eye glasses normally worn when reading, the individual covers one eye at a time. With the uncovered eye, the individual stares at the dot in the center of the grid. All four corners of the grid should be visible, and the lines of the grid should appear to be straight and continuous from top to bottom and side to side. If there appear to be any holes or blurry spots, or the lines look wavy, fuzzy, crooked, distorted or broken, the individual should call their eye doctor immediately.