Age Related Macular Degeneration (AMD)
Age related macular degeneration (AMD) is one of the most common causes of poor central vision after age 60 and is caused by both genetic and environmental causes. In recent years, numerous genetic mutations have been identified which predispose to the development of the disease. Increasing age, smoking, high blood pressure, cardiovascular disease, and blue eyes have also been identified as risk factors.
Nine out of 10 people who have AMD have the dry form, which is characterized by drusen, pigment alterations and atrophy in the macula (the central portion of the retina). Drusen are small deposits that gradually accumulate under the macula over many years. In most patients, drusen cause only minimal visual problems and require no medical treatment. The most common cause of vision loss in patients with dry AMD is atrophy, or thinning of the central macula. Like drusen, atrophy tends to worsen very gradually over many years. If the atrophy involves the central macula, straight-ahead vision is often impaired. Dry AMD takes many years to develop. Currently there is no treatment available to reverse the effects of dry AMD.
However, a study by the National Institutes of Health called the Age-Related Eye Disease Study (AREDS) showed that certain vitamins can reduce the risk of vision loss. For more information, see AREDS. Controlling blood pressure, eating a well-balanced diet rich in green, leafy vegetables and not smoking have also been shown to slow the progression of the disease.
The wet form of AMD occurs much less frequently (one out of 10 people with AMD) but is associated with more severe visual problems. Wet AMD is characterized by the development of abnormal blood vessel growth under the macula called choroidal neovascularization. These abnormal vessels may leak fluid, bleed or scar down compromising central vision. Numerous treatments are now available to treat choroidal neovascularization which have greatly improved our ability to preserve and even improve vision in patients with wet AMD. At The Retina Care Center, we employ the full range of therapies to ensure the best possible outcomes for our patients with wet AMD. Depending on the characteristics of the blood vessel growth, patients may benefit from the latest AMD drugs such as Avastin, Lucentis or the newly approved Eylea. Older treatment modalities such as laser photocoagulation and photodynamic therapy are also available and may prove beneficial for select patients. Promising AMD research is being done on many fronts and The Retina Care Center continues to participate in national clinical trials to identify and test new therapies. Our participation in the VIEW-1 trial helped to prove the efficacy of Eylea which just received FDA-approval in November 2011.
While AMD may cause loss of central vision to a level that is considered “legally blind” (20/200 or worse in both eyes), it virtually never affects peripheral or side vision. Furthermore, with the introduction of new therapies, the risk of legal blindness has fallen by about 50% in the past 10 years.
For more information about Age related macular degeneration, please see: www.geteyesmart.org