By Dr. Christopher Tortora, M.D.
Medical Director of Hawaiian Eye Center and Dry Eye Clinic
February is designated Age-Related Macular Degeneration (AMD) Awareness Month to help educate the public on this serious eye disease that affects over 2 million Americans and is the leading cause of severe vision loss for those 50 years of age and older. AMD develops as a person ages and can greatly diminish central vision.
AMD is a progressive and usually painless eye disease that occurs when the eye’s macula starts to deteriorate. The macula is the small central portion of the retina—the light-sensitive tissue lining the back of the eye.
AMD develops slowly over time and symptoms often go unnoticed until there is significant eyesight damage. AMD causes central vision to blur while peripheral vision is unaffected. Central vision allows a person to see straight ahead and distinguish fine details.
There are two forms of AMD—dry and wet. The dry form is the most common and is a result of drusen, white or yellow fatty protein deposits, in the macula. As drusen grow and multiply, eyesight becomes dimmed or distorted. In advanced stages, the macula becomes thinner and can lead to blind spots or complete loss of central vision.
The wet form of AMD is far less common but advances much more rapidly. Abnormal blood vessels grow underneath the macula and leak blood and fluid into the retina. The abnormal blood vessels eventually scar and cause permanent loss of central vision. In some cases, dry AMD can turn into wet AMD.
Symptoms of AMD include dark, blurry spots in the center of vision and a decrease in the brightness of colors. Wet form symptoms will appear and advance quickly, while dry form symptoms tend to go unnoticed until later stages of AMD.
Early detection of AMD is vital in preserving eyesight. Those 50 and older should get a comprehensive dilated eye exam from an eye doctor at least once a year to check for AMD and other eye diseases. If early AMD is detected, more frequent eye exams may be needed to see if the disease is progressing.
There is currently no treatment for early AMD and no cure for the dry form. However, the National Eye Institute did extensive studies that showed high doses of certain vitamins and minerals (including vitmain C, vitamin E, zinc, copper, lutein and zeaxanthin) can help to slow the progression for those with intermediate or late AMD. Nutritional supplements based on these studies are available from a number of manufacturers and may be referred to as AREDS or AREDS2 (Age-Related Eye Disease Studies).
Wet AMD can be treated with variety of procedures that help to close off broken blood vessels and slow the growth of new abnormal blood vessels. Treatments include injecting drugs directly into the eye or via the arm with an accompanying laser beam to the eye that activates the drug, known as photodynamic therapy. Laser surgery, which differs from photodynamic therapy, is used far less often and involves aiming a high-energy beam that burns the abnormal blood vessels.
Even with treatment, AMD may still progress or reoccur. It’s important to speak with an eye care professional about treatment options and risks.
Risk factors for AMD include: being 50 and older, smoking, obesity, hypertension, high cholesterol and a family history of the disease. Caucasians and women are also more likely to develop AMD.
The best way to help prevent AMD or limit its effects is to exercise regularly, maintain a healthy diet and not smoke.