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Age-Related Macular Degeneration
Age-related macular degeneration (AMD) is a condition that primarily affects the part of the retina
responsible for sharp central vision. There are two forms:
- Dry AMD (non-exudative) is the most common form of the disease.
Early AMD involves the presence of drusen, fatty deposits under the light-sensing
cells in the retina. Late cases of dry AMD may also involve atrophy of the
supportive layer under the light-sensing cells in the retina that helps keep
those cells healthy. Vision loss in early dry AMD is usually moderate and
only slowly progressive. Atrophy in late cases of dry AMD can result in
more significant vision loss.
- Wet AMD (exudative) is less common, but is more threatening to vision.
It's called wet AMD because of the growth of tiny new blood vessels
(neovascularization) under the retina that leak fluid or break open. This
distorts vision and causes scar tissue to form. All cases of the wet form
are considered late AMD.
The exact cause of AMD is unknown, but risk factors for the disease include
age (rarely affecting those under age 50), White race and cigarette smoking.
Research also suggests that long-term diets low in certain antioxidant nutrients
may increase the risk of AMD. Because AMD often damages central vision, it is
likely the most common cause of legal blindness and vision impairment in
older Americans.
Unfortunately, there is no generally-accepted treatment for dry AMD. Laser
therapies to destroy leaking blood vessels can help reduce the risk of advancing
vision loss in many cases of wet AMD. Research has recently shown that certain
doses of zinc, vitamins A and C, and beta-carotene can help control the
advance of late AMD, but appear to have no effect in preventing the disease in
otherwise healthy individuals.
Only cases of late AMD involving geographic atrophy or neovascularization are
included in the prevalence estimates on page 19. Over 1.6 million Americans
age 50 and older have late AMD. Age-specific prevalence rates are initially
comparable between races, but advance more significantly for Whites after age
75. In Blacks, the disease is more prevalent in women until about age 75 as well.
Because data are lacking for Hispanics and other races, the rates shown
for these populations are an arithmetic average of the rates for Whites and
Blacks.
Available tables:
- Estimated Number of Cases of Age-related Macular Degeneration in the U.S. Population Aged 50 and over by State, Race and Sex
- Prevalence Rates for Age-related Macular Degeneration by State, Race and Sex
- National age-specific prevalence rates for age-related macular degeneration
- U.S. Census 2000 Population aged 50 and over by Race and Sex
The tables are located on the following page:
Notes:
- The page opens in a new window.
- There are 4 tabs located in the bottom left corner that select the different tables.
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