BUSINESS WIRE
Nutritional and Genetic Studies Point to New Prevention and Treatment
Strategies
SAN FRANCISCO--(BUSINESS WIRE)--Age-Related Macular Degeneration (AMD) is a leading cause of vision loss
in the United States, but discoveries about the roles played by
nutrition, genetic factors and immune response are providing clues to
new prevention and treatment measures. AMD can destroy the detailed,
central vision we need to read, drive, recognize faces, and enjoy daily
life.
March is AMD Awareness Month, and the American Academy of Ophthalmology,
joined by the American Society of Retina Specialists, the Macula
Society, and The Retina Society, encourages Americans to know their
risks for AMD. “We have a greater
understanding of AMD than ever before,” says
Janet S. Sunness, MD, Medical Director of the Hoover Services for Low
Vision and Blindness, Baltimore, Maryland, and an Academy clinical
correspondent. “We are seeing exciting
clinical and research advances, but catching AMD early still offers the
best chance of preserving vision. People need to know their risks so
that they can save their sight.”
As part of the EyeSmart campaign, the Academy and EyeCare America, a
public service program of the Foundation of the American Academy of
Ophthalmology, recommend that adults with no signs or risk factors for
eye disease get a baseline eye disease screening at age 40—the
time when early signs of disease and changes in vision may start to
occur. Based on the results of the initial screening, an ophthalmologist
will prescribe the necessary intervals for follow-up exams. For
individuals at any age with symptoms of or at risk for eye disease, such
as those with a family history of eye disease, the Academy recommends
that individuals see their ophthalmologist to determine how frequently
their eyes should be examined. One of the best ways to reduce AMD risk
is to quit smoking, as smokers have twice the risk of nonsmokers.
New Clues
Certain nutrient supplements are now known to be protective: the first
Age-Related Eye Disease Study (AREDS 1) of 4,000 people with AMD found
that the progression to advanced disease among people at high risk
declined by 25 percent when the subjects were given a high-dose
combination of antioxidants and zinc. Eye MDs recommend this supplement
formula to their AMD patients when appropriate. These nutrients may
strengthen the ability of a layer of cells in the eye’s
retina to withstand oxidative stress, a probable factor in AMD
development. In the second AREDS study now underway, researchers are
assessing lutein, zeaxanthin, and omega-3 fatty acids, associated in
some large studies with reduced risk of developing AMD. Both AREDS
projects were sponsored by the National Institutes of Health. Eating
fruits and deeply colored vegetables such as red peppers and spinach—food
sources of antioxidants—provides many health
benefits, and one is likely to be protection against AMD.
A new model that views a specific type of uncontrolled immune response
as an important factor in AMD development and progression has emerged
from the work of a number of genetic and ophthalmic researchers. The
model promises to spark advances in AMD treatments and genetic
susceptibility tests. In several degenerative diseases—including
Alzheimer’s, atherosclerosis and AMD—the
early phases are marked by abnormal extra-cellular deposits that begin
to disrupt normal functioning. In AMD, these deposits are called drusen,
and they contain proteins associated with inflammation and other immune
system responses.
Four independent research groups recently discovered that variations in
three genes associated with sensitivity of the immune response are also
strongly associated with AMD. Several research groups subsequently
confirmed that two of these genetic variants collectively account for
about 75 percent of AMD cases in North American and European
populations. Another study, by Margaret Pericak-Vance, PhD, Duke
University, and Jonathan Haines, PhD, Vanderbilt University, showed how
a risk factor and genetic variant interact: the risk of AMD increased
eight-fold in study participants who were smokers and had variant
LOC387715.
About AMD
The disease takes two forms, termed “dry”
and “wet.” In the
early “dry” stage,
drusen, yellow deposits, develop under the retina, but most people do
not have a change in vision. Patients with more and larger drusen, and
more pigment changes in the central retina, or macula, are considered to
have intermediate AMD and are at higher risk for both advanced “dry”
and “wet” AMD. The
majority of those with intermediate AMD do not progress to the advanced
stage but should be carefully followed by an Eye MD to insure timely
treatment if needed.
Advanced AMD can occur in the “dry”
or the “wet” form.
Once the “dry”
form reaches the advanced stage, with blind spots in the central visual
field, no medical or surgical treatment is available, although patients
can be provided low-vision technologies, including improved lighting and
magnification, to maintain their quality of life. In the “wet”
form, abnormal new blood vessels develop under the retina that bleed or
leak fluid and form scars, causing central vision loss. Only about 10%
of the 10 to 15 million Americans with AMD have the “wet”
form, but until two years ago it was responsible for most severe vision
loss. New, highly effective treatments such as the injectable
medications ranibizumab and bevacizumab are dramatically reducing damage
from “wet” AMD:
vision stabilizes in over 90 percent of patients and actually improves
in more than 30 percent.
For more information about AMD and other eye diseases, visit www.geteyesmart.org.
For more information on: the American Society of Retinal Specialists,
visit http://www.asrs.org; on the
Macular Society: http://www.maculasociety.org;
and on The Retina Society: http://www.retinasociety.org.
Broadcast Eds: AMD B-roll footage is available from the
Academy. Please contact the Academy’s media
relations department for download information.
About the American Academy of Ophthalmology
The American Academy of Ophthalmology is the world's largest association
of eye physicians and surgeons—Eye M.D.s—with
more than 27,000 members worldwide. Eye health care is provided by the
three “O’s”
– opticians, optometrists and
ophthalmologists. It is the ophthalmologist, or Eye M.D., who can treat
it all: eye diseases and injuries, and perform eye surgery. To find an
Eye M.D. in your area, visit the Academy's Web site at www.aao.org.