What is Age-Related Macular Degeneration (AMD)?
Age-related macular degeneration (AMD) is a condition that affects the cells responsible for our central vision, in the macula. These cells are needed for seeing fine detail (reading, driving etc.). When macular degeneration occurs, these cells become damaged and fail to function normally. This results in symptoms such as blurred, decreased or distorted vision. Because macular degeneration affects central vision, peripheral vision is typically spared.
Why do I have Age-Related Macular Degeneration?
With all the research and advances in medicine we still do not understand why some people develop AMD and others do not. Large randomized controlled trials however have taught us that there are several risk factors:
Age: Your risk of developing AMD increases with age, it is most commonly seen in patients after the age of 60.
Family History: With current research we are learning that genetics plays a greater role than we ever knew. You have a higher risk of developing AMD if someone in your family is affected by it.
Race: AMD is much more common in Caucasians than other races.
Poor Diet: A lack of fruits and vegetables can increase your risk of AMD. Interestingly, recent studies have shown a a mediterranean diet may be protective against the development of AMD.
Smoking: Smoking is the single greatest modifiable risk factor for AMD.
What is the Difference Between Dry and Wet Age-Related Macular Degeneration?
Typically if you carry a diagnosis of AMD it is classified as either dry or wet (also known as neovascular). Typically AMD initially presents as the dry form. Often times the earliest changes from macular degeneration do not cause any symptoms, however your eye doctor can detect these changes during an eye exam. One of the changes your eye doctor may notice are deposits underneath the macula, called drusen. Drusen may cause mild blurring or distortion of your vision, or, as they typically are, not cause any noticeable changes in your vision. If your Dry AMD progresses, it may permanently damage the cells in the macula and lead to advanced changes called geographic atrophy. These damaged areas are where the actual retinal cells are no longer functioning and lead to blind spots in your vision. Unfortunately at this time there is no treatment available for Dry AMD.
Wet AMD refers to the development of abnormal leaking blood vessels underneath the macula, which in some instances can bleed. Whether these blood vessels leak or bleed patients often notice a sudden and dramatic change in their vision. If this occurs, it is important that you are evaluated by your doctor as soon as possible. Receiving early treatment is important in shutting the abnormal blood vessels down and hopefully preventing further damage.
Without treatment, the abnormal blood vessels will continue to leak and/or bleed causing irreversible scarring in the macular and may eventually destroy central vision. Thankfully only 10% of patient with Dry AMD convert to Wet AMD.
How is AMD diagnosed?
The presence of AMD can typically be determined during a dilated eye exam. Testing to support in the diagnosis of AMD include Optical Coherence Tomography (OCT) and Fluorescein Angiography (FA). These tests are used to diagnose and help guide response to treatment. They also can help determine the severity of the disease and whether you have dry or wet AMD.
If I have Dry AMD, what can I do to decrease my chances of developing Wet AMD?
1. Eye Vitamin supplementation and a diet high in green leafy vegetables (discuss with your primary care doctor before starting)
2. Self monitoring with Amsler grid testing.
A large clinical trial performed by the National Eye Institute called the Age-Related Eye Disease Study 2 (AREDS2) found the following formulation most beneficial: Vitamin C (500mg), Vitamin E (400IU), Lutein (10mg), Zeaxanthin (2mg), Zinc (80mg), Copper (2mg). There are many different brands of these over-the-counter tablets available on the market. It is important to remember that these vitamins are not a cure for Dry AMD. The ARED Study also found that if you don’t have any signs of macular degeneration or have very early signs of Dry AMD, these vitamins are of no benefit in risk reduction. It has also been shown that making certain dietary changes can also help in reducing your risk of progression; a diet high in a variety of colorful fruits and vegetables, choosing healthy unsaturated fats over saturated fats, choosing whole grains over refined grains and adding a good source of omega-3 fatty acids. You can also monitor for any changes yourself with an Amsler Grid. You can get a copy of the grid at our office.
Amsler Grid self testing instruction:
It is preferable to test yourself in the same location, lighting conditions and glasses. It is importance to test each eye separately.
1. Cover one eye and look at the central dot with the uncovered eye.
2. Note if any of the lines look bent or wavy, or if sections of the grid are blurry or missing.
3. Repeat for other eye
4. If you notice any changes you should call our office right away, as this could be a sign of progression of disease.
If I develop Wet AMD, what is the treatment?
Unfortunately at this point in medical science there is no cure for wet AMD. If however, abnormal blood vessels due develop they can be shut down with medications that are injected directly into the eye. These medications include: Avastin (Bevacizumab), Lucentis (Ranibizumab) and Eylea (Aflibercept). Initially these injections are given every 4 weeks until the blood vessels leakage/bleeding is controlled and the vessels are shut down. Subsequently, the interval between injections may be increased or decreased as much as your eye can tolerate. In most instances however, you will likely need continued injections to keep the blood vessels shut down and maintain your vision. In some cases laser treatment or the abnormal blood vessels is indicated and may aid in shutting the abnormal blood vessels down.