Age-related macular degeneration    
Age-related macular degeneration (AMD) is a debilitating eye disease affecting about 15 million
American. It is the most common cause of severe vision loss among people over 60.

Age-related macular degeneration (AMD) appears in two forms, the more common "dry" form and the
less common "wet" form. The wet form is responsible for 10 percent of disease cases, but can very
quickly lead to blindness. While, the dry form is responsible for 90 percent of disease cases, it
progresses more slowly. The symptoms may include blurry or fuzzy vision, difficulty recognizing familiar
faces, 'wavy' straight lines, dark or empty area appears in the center of vision and rapid loss of central
vision.

Age-related macular degeneration (AMD) destroys central vision by attacking macula (locates in the
center of retina). Because only the center of vision is affected, people rarely go blind from this disease.
However, AMD can make suffers difficult to read, drive, and play sports, watching movies and
television. In normal aging process, yellowish waste deposits accumulate around the macula, but in
individuals with AMD, these yellowish waste deposits are larger and more numerous.

Researchers at Yale School of Medicine have identified a gene (known as complement factor H (CFH))
for AMD on a region of chromosome 1 using interdisciplinary approach. They also found that both
forms are associated with the same variant in the CFH gene.


Prevention (Lowering the risk of AMD)



   Avoid smoking
   Exercise regularly
   Maintain normal blood pressure and cholesterol levels
   Eat a healthy diet rich in green, leafy vegetables and fish


Possible Treatments-

Currently, no treatment exists for early AMD, which in many people shows no symptoms or loss of
vision. Researchers at the National Eye Institute tested whether taking nutritional supplements could
protect against AMD in the Age-Related Eye Disease Studies (AREDS and AREDS2). They found that
daily intake of certain high-dose vitamins and minerals can slow progression of the disease in people
who have intermediate AMD, and those who have late AMD in one eye. The first AREDS trial showed
that a combination of vitamin C, vitamin E, beta-carotene, zinc, and copper can reduce the risk of late
AMD by 25 percent. The AREDS2 trial tested whether this formulation could be improved by adding
lutein, zeaxanthin or omega-3 fatty acids.  Lutein, zeaxanthin and beta-carotene all belong to the same
family of vitamins, and are abundant in green leafy vegetables.

Here are the clinically effective doses tested in AREDS and AREDS2:

  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

For advanced neovascular AMD, there are three types of treatments - injections, photodynamic
therapy and laser surgery.
(1) With neovascular AMD, abnormally high levels of vascular endothelial
growth factor (VEGF) are secreted in your eyes. VEGF is a protein that promotes the growth of new
abnormal blood vessels. Anti-VEGF injection therapy blocks this growth. If you get this treatment, you
may need multiple monthly injections.
(2) Photodynamic therapy involves laser treatment of select
areas of the retina. First, verteporfin will be injected into a vein in your arm.Verteporfin travels through
the blood vessels in your body, and is absorbed by new, growing blood vessels. Your eye care
professional then shines a laser beam into your eye to activate the drug in the new abnormal blood
vessels, while sparing normal ones. Once activated, the drug closes off the new blood vessels, slows
their growth, and slows the rate of vision loss.
(3) Laser surgery involves aiming an intense "hot" laser
at the abnormal blood vessels in your eyes to destroy them. Laser treatment may destroy some
surrounding healthy tissue. This often results in a small blind spot where the laser has scarred the
retina. In some cases, vision immediately after the surgery may be worse than it was before. But the
surgery may also help prevent more severe vision loss from occurring years later.


SOURCE OF INFORMATION: NIH, National Eye Institute.

Herb / nutritional supplements: ginkgo biloba [2], vitamins C and E, and lutein and zeaxanthin [3]
While, Johnson EJ and Schaefer EJ at Jean Mayer U.S. Department of Agriculture Human Nutrition
Research Center on Aging at Tufts University suggested DHA in fish and fish oil might be helpful on
reduction in the risk. [5]

References
2. Evans JR. Ginkgo biloba extract for age-related macular degeneration, Cochrane Database Syst
Rev. 2000;(2):CD001775 3. Bartlett H et al, An ideal ocular nutritional supplement? Ophthalmic Physiol
Opt. 2004 Jul;24(4):339-49. [5] Johnson EJ and Schaefer EJ., Potential role of dietary n-3 fatty acids in
the prevention of dementia and macular degeneration. Am J Clin Nutr. 2006 Jun;83(6 Suppl):14945-
1498S.
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