Age-related macular degeneration: what you need to know

US population – 318.8 million
US population over 60 – 60.5 million
US population with age-related macular degeneration – 15 million

Age-related macular degeneration (AMD) is the number one cause of blindness over the age of 60. As the population continues to age, AMD will continue to cause millions of people to lose their vision.

Image courtesy of Sohrab  Gollogly website at www.sohrabgolloglymd.com

Image courtesy of Sohrab
Gollogly website at http://www.sohrabgolloglymd.com

So what is AMD and how can it be treated?

Age-related macular degeneration is the breakdown of the light sensing tissue in the back of the eye – the retina. In the normal process of seeing, as light hits the nerves in the retina, the nerves go through a chemical change in order to send a signal to the brain saying, “light, hit me.” As the nerves go through this change, they slough off a lipo-protein material called drusen that is cleaned up by the layers below the retina. In the normal process of aging, these garbage collectors in the retina don’t do their job as well and with time, drusen begins to deposit. These cells are important, not only for cleaning up the debris of seeing, but also for bringing nutrients to the retinal. In AMD, there is a faster than normal aging in the retina, resulting in a greater buildup of drusen and eventually the loss of the light sensing nerves and loss of vision.

Most people who develop AMD develop a slow loss of vision over many years. This is the definition of “Dry” AMD. In about 15 percent of patients, the body’s response is to grow new blood vessels into the damaged area of the retina in order to try to fix the problem. These new blood vessels are poorly constructed and leak badly. This “Wet” form of AMD causes bleeding in the retina and a rapid loss of vision within weeks to months.

Unfortunately, there is no treatment for macular degeneration. In some cases, the use of lasers or injections of medications into the eye can “dry up” wet-AMD, but cannot stop the slow steady loss of vision. Fortunately, AMD does not cause complete blindness, only the loss of central vision. However, dealing with the loss of vision from AMD can be difficult. Fortunately, the use of magnifiers and other low vision devices prescribed by low vision specialists can help significantly with the activities of daily living.

The goal of treatment is early detection and mitigation of vision loss. Detection can only happen by the examination of the eye by a doctor of optometry or ophthalmology using special instruments to examine the inside of the eye.

Researchers at the National Eye Institute tested the use of nutritional supplements to protect against AMD. This Age-Related Eye Disease Study 2, AREDS2, found that daily supplements of certain vitamins and minerals can slow progression of vision loss in people who have intermediate AMD, and those who have severe AMD in one eye. The AREDS2 study recommends the following nutritional supplements for patients who have AMD:

  • 500 milligrams (mg) of vitamin C
  • 400 international units of vitamin E
  • 80 mg zinc as zinc oxide (25 mg in AREDS2)
  • 2 mg copper as cupric oxide
  • 15 mg beta-carotene, OR 10 mg lutein and 2 mg zeaxanthin

In addition, other factors increase the risk of developing AMD – smoking, obesity, UV light absorption, systemic vascular diseases, and poor nutrition. So it is important to quit smoking, wear glasses that inhibit UV light, eat a diet high in fruits and vegetables and have yearly eye exams to detect AMD in its early stages. Remember, there are no symptoms until the later stages of the disease, so eye examinations by doctors of optometry and ophthalmology are the only way to determine if you are at risk of developing vision loss from age-related macular degeneration.

 

~ Dr. Steven Sage Hider, OD
California Optometric Association
http://www.coavision.org
http://www.eyehelp.org