Age-Related Macular Degeneration (AMD) is a disease that damages the macula, the central portion of the area at the back of the eye called the retina. The macula allows for central vision and also lets you see color and fine detail—all of which are important to daily activities such as reading and driving. The macular damage caused by AMD causes central vision loss. In most cases, patients will retain peripheral vision and be able to see shapes, light and movement. There are approximately 25 million Americans affected with AMD.
There are 2 kinds of age-related macular degeneration (AMD): dry and wet. Dry AMD is more common, representing approximately 90% of all AMD cases, and is generally not as damaging to vision as the wet form. Dry AMD can convert into wet AMD at any time. This is the reason why frequent follow up of those with early Dry AMD or a family history of AMD is so important.
In Dry AMD, yellowish, fatty deposits called drusen collect in the macula. Most dry AMD patients have no symptoms, and an eye doctor may need to conduct a variety of tests to aid in diagnosis. There are no approved treatments for dry AMD, although vitamins, antioxidants and zinc supplements may slow its progression. Diets rich in nutrients are known to slow the progression of AMD in those with or without genetic risk. As many as 20% of Dry AMD patients will progress to wet AMD. There is currently a genetic test (MaculaRisk(R) that can predict with 83% accuracy the likelihood that a patient with Dry AMD will progress to Wet AMD.
Wet AMD occurs when abnormal blood vessels grow under the retinal center, called the macula. These vessels may be very fragile and leak blood and fluid which can damage the macula. Due to the rapid onset of macular damage, a noticeable blurring or even loss of central vision are frequently the first symptoms noted. The vision loss may be permanent because abnormal blood vessels and scar tissue are actually destroying normal retinal tissue. Once lost, these light-sensitive cells in the retina cannot be replaced. If a person has wet AMD in one eye, there is a 35% chance of contralateral wet AMD within 5 years. The most important action to preserve vision is to establish a schedule of regular retinal re-evaluation by an eye care professional. Treatment for Wet AMD involves injections into the affected eye with an anti-VEGF drug (Lucentis, Avastin) once monthly. Anti-VEGF treatment can slow the progression of Wet AMD and it is important that a diagnosis is made early before damage occurs.