Age-Related Macular Degeneration (AMD) is the most common cause of severe vision loss in older Americans. It affects central vision and may interfere with daily tasks, such as reading and driving. Several of our retina specialists have developed a particular focus on this disease, and have been instrumental in developing innovative treatments to control and reverse the effects of AMD.
Early symptoms include blurred vision or distortion, such as objects appearing warped, or straight lines appearing wavy. Your ophthalmologist can often detect signs of AMD before any loss of vision occurs.
Forms of AMD
Macular degeneration affects the retina in two forms – dry and wet AMD.
The dry form of AMD is more common, and is generally not associated with severe loss of vision. It is characterized by the presence of small, yellowish deposits under the retina, called drusen. This early form of macular degeneration does not cause any visual symptoms. Thus, a complete eye examination by an ophthalmologist is recommended annually if you are age 50 or older. These regular examinations provide an opportunity to look for signs of the disease, particularly if there is any history of macular degeneration in your family.
If you have the early form of AMD, studies have shown that you can reduce your chances of loss of vision by not smoking, maintaining a healthy diet (including fruits and vegetables rich in antioxidants), and working with your doctors to control your blood pressure and lipids. You can also perform a simple test at home, using an Amsler grid, to look for signs of worsening vision caused by AMD.
The wet, or neovascular, form of AMD, is frequently accompanied by relatively sudden loss of vision. This is caused by the growth of abnormal blood vessels underneath the retina that leak fluid or blood. Recent advances in the treatment of wet AMD can now prevent further loss of vision, or even restore vision in some cases, if treatment is sought promptly.
There is no known cure for either wet or dry forms of AMD. However, most patients with the dry form do not experience severe visual loss.
Treatment for Dry AMD
Certain patients with intermediate forms of dry AMD may benefit from a specific vitamin formulation that has been shown in clinical trials to decrease the chance of developing the more advanced stages of AMD. Please note that the Age Related Eye Diseases Study (AREDS) tested the benefit of a defined vitamin formulation that may be different from over-the-counter supplements. You should consult with your ophthalmologist or retina specialist to verify whether you are a candidate for AREDS vitamins, and to determine which formulation is right for you.
If you have the early form of AMD, studies have shown that you can reduce your chances of loss of vision by not smoking, maintaining a healthy diet, and working with your doctors to control your blood pressure and lipids. Colorful fruits and vegetables rich in antioxidants, fish rich in omega-3 fatty acids, and nuts are all considered to be beneficial with regard to prevention of the advanced form of AMD.
Treatment for Wet AMD
There have been great strides in the treatment of the wet, or neovascular, form of AMD in the past few years. For instance, researchers at Mass. Eye and Ear and Harvard Medical School found that vascular endothelial growth factor (VEGF) is involved with stimulating abnormal blood vessel growth in ocular diseases. Because of this knowledge, most patients who begin to experience vision loss due to the abnormal growth of new vessels in AMD can maintain stable vision, or perhaps even experience improvement, in vision following prompt treatment with a new class of medications that block this new blood vessel growth.
Anti-VEGF treatments seek to stop the abnormal blood vessel growth of wet AMD and prevent vision loss. Currently, the most commonly used anti-VEGF agents are ranibizumab (Lucentis™), approved for the treatment of wet AMD by the FDA in 2006, and bevacizumab (Avastin™). These medications are delivered via injection into the degenerating eye. Injections are generally performed monthly, but may occur at less frequent intervals – your retinal specialist will explain the dosing schedule and rationale.
Injections of anti-VEGF agents are performed in an outpatient office setting and are generally well-tolerated. Most patients are able to resume their daily activities immediately. You will be instructed to use antibiotic eye drops for several days following your injection. While anti-VEGF agents are relatively safe, there are rare associated risks – you will have the opportunity to discuss the risks and benefits of anti-VEGF treatment with a retinal specialist. If you experience worsening vision, pain, or progressive eye irritation and redness following an injection, contact your retinal specialist immediately.
Prior to the advent of anti-VEGF agents for AMD, many patients with the wet form of AMD were treated with Photodynamic Therapy (PDT), a type of "cold laser" therapy using the photosensitizing drug verteporfin (Visudyne™), developed by a collaborative effort between Mass. Eye and Ear and Massachusetts General Hospital. Currently, PDT is rarely used as a stand-alone therapy for wet AMD, but is under investigation as one component of "combination therapies" for wet AMD. Thermal laser photocoagulation, or "hot laser," is also uncommonly used, but researchers continue to investigate the role of novel laser technologies in AMD.
If you have lost vision in one or both eyes from AMD, you may benefit from Vision Rehabilitation at Mass. Eye and Ear. This Center has offered vision rehabilitation services for more than 25 years to patients with eye conditions that restrict daily activities, mobility, productivity, or independence. The goal of vision rehabilitation is to help patients effectively use all of their remaining vision. It is part of the continuum of eye care, just as stroke rehabilitation or cardiac rehabilitation is part of the continuum of health care. Patients continue to receive treatment from a retinal specialist while participating in rehabilitation.