Age-related macular degeneration (AMD) is a deterioration or breakdown of the eye's macula. The macula is a small area in the retina — the light-sensitive tissue lining the back of the eye. The macula is the part of the retina that is responsible for your central vision, allowing you to see fine details clearly. Tiny dot-like deposits known as drusen slowly accumulate beneath the macula. While these deposits usually do not cause visual loss directly, they indicate that the patient is at risk for developing further problems with the macula. Usually, these deposits would not be apparent before the age of 50.
Visual problems in macular degeneration take two basic forms. The first, milder problem occurs as the cells of the macula slowly lose sensitivity and may become less numerous. This may result in fluctuating vision—the sight is clearer on some days than others—and slowly (typically over months to years) vision may worsen. This is referred to as the “dry” form of macular degeneration.
The second type of problem occurs more suddenly and may cause a more serious drop in vision. Tiny clusters of abnormal blood vessels may begin to grow beneath the macula. These vessels “leak” and blood or watery fluid may accumulate beneath the macula. This can result in irreversible damage to the macula, resulting in loss of the central detail vision. The presence of leaks is often referred to as the “wet” form of macular degeneration.
If these vessels can be identified at an early stage, and they are outside the exact center of the macula, it may be possible to seal them with laser treatment. In most cases, however, laser cannot be used because the vessels have already spread too far, or the exact location of the leak cannot be found. Fortunately, there are some newer treatments that offer greater hope for vision improvement despite the limitations of laser treatment.