About 8.5 million Americans over the age of 40 suffer from vision loss due to AMD. Though its cause is unknown, AMD results when changes occur to the macula, a portion of the retina located at the back of the eye. The macula provides our central vision and allows us to see fine detail such as recognizing a face, reading, or watching television. When the macula becomes damaged, extreme and dramatic vision loss can occur.
Early symptoms of AMD are the appearance of spots beneath the retina. The spots, called drusen, are small, round lesions. They usually do not change vision very much and most people with drusen will never have a serious loss of vision. Other common symptoms include the gradual loss of the ability to see objects clearly, distorted vision, a gradual loss of color vision and a dark or empty area in the center of your vision. Most changes occur gradually and begin in only one eye. Because the healthy eye compensates for the weaker eye, these changes may go unnoticed for a while.
There are two forms of the late stages of AMD: dry AMD and wet AMD. When the early stages of drusen (the spots mentioned above) are present for an extended period of time, they cause the macula to become thinner and cease functioning. This is referred to as the dry form of AMD. People with this type may have "blank" areas in their central vision. No treatments are available at this time, but various vision aids such as magnifiers are available and can help people live their lives as normally as possible.
Wet AMD is caused by the growth of abnormal blood vessels across the macula and retina. As these vessels leak fluid and blood into the tissue at the back of the eye, scar tissue typically forms and vision loss may occur. This activity is responsible for up to 90% of the severe vision loss associated with AMD. There are two forms of treatment for wet AMD. One is using a laser to stop any leakage and destroy the abnormal blood vessels. This treatment results in a scar, which can leave a permanent blind spot in the field of vision. Usually this loss of vision is less severe than if the AMD had gone untreated. The other form of treatment for wet AMD is Visudyne therapy. In this procedure a light-activated drug (Visudyne) is injected into the patient's bloodstream. It is then activated by a non-thermal laser. This produces a clot that closes the abnormal blood vessels without causing damage to the retina. If you suffer from any type of vision loss or suspect that you might be at risk for AMD, contact Dr. Howell immediately for a comprehensive examination. It is important to treat this as quickly as possible to prevent additional vision loss. AMD may be hereditary and anyone over 40 who has a relative with AMD should have a retinal exam every two years.