What is Macular Degeneration?
As the name “age-related” suggests, the chances of developing AMD increase with age, especially over 65. It tends to run in families, although having one or even both parents with AMD does not automatically mean their children will develop the disease. Other major risk factors include smoking, obesity, high blood pressure and sunlight exposure.
The “degeneration” in macular degeneration refers to a breaking down of the macula. The macula is the very center of the retina and is responsible for the fine detail vision needed to drive or read. Since AMD only affects the center of the retina, it does not lead to total blindness. However, in severe cases it can cause vision to deteriorate to the point where driving and reading become difficult or impossible.
There are two types of macular degeneration: dry and wet.
Dry macular degeneration accounts for about 80% of cases. It causes a slow, gradual decrease in vision and is typically less severe than wet AMD.
With dry AMD, the changes in the macula lead to a slow, gradual loss of vision over many years. The loss of vision may be so slow and gradual that no change is noticed from one year to the next. Patients with dry AMD generally do not lose central vision entirely, but vision loss can make certain tasks like driving or reading difficult or impossible.
Wet macular degeneration accounts for roughly 20% of cases of AMD. In wet AMD, abnormal blood vessels grow underneath the macula and leak blood and fluid. This leakage causes a decrease in vision which can occur rapidly.
Wet AMD usually causes more severe vision loss than dry AMD, although new treatments are available that may slow or even stop the leakage. Most people who develop wet AMD first develop dry AMD that converts into the wet kind.
How is AMD Treated?
Patients with mild to moderate cases of dry AMD can lower their risk of developing wet AMD and preserve their vision by taking a daily dose of antioxidant vitamins and minerals. These findings are the results of several large clinical trials known as AREDS 1, AREDS 2, and the LAST trial.
The vitamins and minerals in the study were:
- Vitamin C 500 mg
- Vitamin E 400 IU
- Zinc 80 mg
- Copper 2 mg
- Lutein 10 mg
- Zeaxanthin 2 mg
Patients with dry AMD who took these vitamins and minerals reduced their risk of developing wet AMD. Many also showed improvement in visual function such as improved ability to recover from glare from bright lights and vision in low contrast (e.g. driving in rain) situations.
One important finding of these studies was that vitamin A (beta carotene) was not helpful for AMD patients. In fact, recent studies suggest that smokers (and former smokers) who take too much vitamin A may increase their risk of lung cancer.
It isn’t possible to get enough vitamins and minerals in the AREDS 2 formula by diet alone. However, eating a diet rich in green, leafy vegetables (spinach, kale, etc.) can lower your risk of AMD. Fruits and vegetables with intense colors like red, yellow, and blue, along with fatty fish like salmon and tuna may also lower your risk of AMD
New treatments for dry AMD are in development and under study, including stem cell and gene transplantation therapy, as well as newer medications to improve retinal health. None have been FDA approved at this time.
For wet AMD, a new generation of treatments has been sight-saving to many people. It involves the injection of medications that slow down and even completely stop growth and leakage of abnormal blood vessels. While the injections are not always effective and multiple injections are usually needed, they do offer hope against the worst complications of AMD.
Lastly, many patients with vision loss from AMD can live a fuller life through vision rehabilitation, or low vision services. While they do not restore vision that has been lost, they can help you or your loved one make the most of the vision they still have. Options include large screen devices, specialized magnifiers, and audio assistants such as Alexa and Siri.