By Mark Siegel
Age-related macular degeneration (AMD) is a leading cause of severe vision loss among Americans ages 65 and over. Knowing your risk factors, being aware of your family history, and keeping regular appointments with your ophthalmologist can help reduce your risks for vision loss from macular degeneration. In its most severe form, known as wet AMD, the disease can lead to permanent loss of central vision which is essential for driving, reading, and recognizing faces.
The past few years have been marked by significant improvement in understanding the causes and the treatment of AMD. New research and clinical advances are helping us to better treat both the “dry” AMD and “wet” forms of AMD. One strong risk factor that people may not be aware of is family history. It’s important to find out whether your relatives have had AMD, and to tell your ophthalmologist, if you have a history of AMD in your family. Knowing your risks can save your sight.
Here are the top five risk factors for AMD:
• Being over the age of 60
• Having a family history of AMD
• Cigarette smoking
If you have any two of these risk factors, you should schedule an appointment with your ophthalmologist for a complete evaluation. Your ophthalmologist may recommend certain preventive measures which can reduce your risk of vision loss from this disorder.
People who are at risk should know the symptoms of wet AMD, the form most likely to cause rapid and serious vision loss. These include sudden, noticeable loss or distortion of vision, such as seeing “wavy” lines. See an ophthalmologist right away if these symptoms occur. Current treatments for wet AMD provide an excellent chance of stopping vision loss and may actually restore some vision when macular degeneration develops. Earlier diagnosis of wet AMD gives a better chance of successful treatment.
There are some AMD risk factors that a person can change such as smoking and diet to reduce the risk of vision loss from AMD. Other risk factors such as genetic factors cannot be changed. However, knowing your family medical history is one way to learn whether you may be genetically predisposed to a disease. One way to reduce AMD risk is to quit smoking or never start. For patients at high risk for developing late-stage AMD, taking a dietary supplement of vitamin C, vitamin E and beta carotene, along with zinc, has been shown to lower the risk of AMD advancing to advanced stages by 25 percent. Patients should check with their ophthalmologist and primary care physician before starting any dietary supplement.
The disease takes two forms, termed “dry” and “wet.”
• Early-stage AMD: Yellow deposits called “drusen” develop under the retina, the light-sensitive tissue at the back of the eye that focuses images and relays them to the optic nerve. At this stage, most people do not have reduced vision.
• Intermediate AMD: Patients have more and larger drusen and more pigment changes in the macula (the part of the retina responsible for central vision); they are at higher risk for both advanced dry and wet AMD. The majority of those with intermediate AMD do not progress to an advanced stage, but should be followed by an ophthalmologist so they can be treated if needed.
• Advanced “dry” AMD: Patients with more advance dry AMD may have a blind spot in their central vision. Currently there is no proven therapy to restore vision lost from advanced dry AMD. Low-vision technologies, including improved lighting and magnification, help maintain their quality of life.
• Advanced “wet” AMD: In this stage, abnormal blood vessel form under the retina. These blood vessels can leak fluid or bleed and cause sudden and drastic loss of central vision.
Although only about 10 percent of the 10 to 15 million Americans with AMD have the “wet” form, it is responsible for the most severe vision loss. New, highly effective treatments such as the injectable medications ranibizumab and bevacizumab are dramatically reducing damage from “wet” AMD and can stabilize vision in more than 90 percent of patients and actually improve vision in up to 30 to 40 percent of patients.