Emory Eye Center Reports Important
Findings from National AREDS Study: Macular Degeneration Progression
Can Be Slowed for Those at High Risk
(ATLANTA) Findings were released today detailing the results
of an important 10-year study which had a two-fold purpose:
- To assess the clinical course, prognosis, and risk factors of age-related
macular degeneration (AMD) and cataract.
- To evaluate, in randomized clinical trials, the effects of pharmacologic
doses of (1) antioxidants and zinc on the progression of AMD and (2)
antioxidants on the development and progression
Titled the Age- Related Eye Disease Study (AREDS), the clinical
trial was conducted at 11 centers across the country, including the
Emory Eye Center. The results show that there is a relatively simple
way to help prevent the progression of age-related macular degeneration
(AMD) in patients at high risk of the disease. "This is a particularly
important finding since prior to this study, there was no way to slow
the progression of AMD," says principal investigator Daniel F. Martin,
M.D., a vitreoretinal specialist at the Emory Eye Center. The AREDS
was sponsored by the National Eye Institute (NEI), one of the federal
government's National Institutes of Health. The study’s findings are
reported in the October issue of Archives of Ophthalmology.
AMD is the leading cause of visual impairment and blindness in Americans
over 65 years of age. It affects the sharp, central vision required
for "straight ahead" activities such as reading, driving and recognizing
faces. The AREDS results show that a dietary supplement of high levels
of antioxidants and zinc significantly reduced the risk of advanced
AMD and its associated vision loss in patients at high risk of developing
advanced stages of AMD.
These same supplements had no significant effect on the development
or progression of cataract, the study found. Although the current study
indicated that the dietary supplements did not affect the development
of cataract, an effect over a longer period of timeor with different
doses of these antioxidantscannot be ruled out.
The three stages of AMD analyzed in the study included:
- Early AMD: Patients with early AMD have, in one or both eyes, either
several small drusen (yellow deposits under the retina) or a few medium-sized
drusen; these patients do not have vision loss from AMD.
- Intermediate AMD: Patients with intermediate AMD have, in one or
both eyes, either many medium-sized drusen or one or more large drusen;
in these people, there is usually little or no vision loss.
- Advanced AMD: In addition to drusen, patients with advanced AMD
have, in one or both eyes, either: (1) a breakdown of light-sensitive
cells and supporting tissue in the central retinal area (advanced
dry form); or (2) abnormal and fragile blood vessels under the retina
that can leak fluid or bleed (wet form).
These two forms (wet or dry) of advanced AMD can cause serious vision
loss. Scientists are unsure why an increase in the size and number of
drusen can lead to advanced AMD, but patients who have advanced AMD
in one eye are at especially high risk for developing it in the other
The AREDS scientists found that their patients at high risk of developing
advanced stages of AMD lowered this risk by approximately 25 percent
when treated with a high-dose combination of Vitamin C, vitamin E, beta-carotene
and zinc. "High risk" is defined as: 1) intermediate AMD in one or both
eyes; and 2) advanced AMD in one eye, but not the other eye.
In the same high-risk groupwhich includes people with intermediate
AMD, or advanced AMD in one eye but not the other eyethe supplements
reduced the risk of vision loss caused by advanced AMD by about 19 percent.
For those study participants who had either no AMD or early AMD, the
supplements did not provide an apparent benefit.
What This Result Means
For people at high risk for developing advanced AMD, these supplements
are the first effective treatment to slow the progression of the disease.
Current treatment for advanced AMD is quite limited. These dietary supplements
will delay the progression to advanced AMD in those people who are at
high risk (those with intermediate AMD in one or both eyes, or those
with advanced AMD in one eye already).
The supplements are not a cure for AMD, nor will they restore vision
already lost from the disease. They will, however, help those at high
risk from developing an advanced stage of the disease and help them
keep their vision.
What Are the Supplements?
The supplements used in the study which slowed the progression to advanced
AMD consisted of several antioxidant vitamins. They also contained zinc.
The supplements contained 500 mg of vitamin C; 400 IU of vitamin E;
15 mg of beta-carotene; 80 mg of zinc as zinc oxide; and 2 mg of copper
as cupric oxide (to help prevent copper deficiency, which may result
from high levels of zinc supplementation). Although previous studies
have shown that diets rich in green, leafy vegetables lower the risk
of developing AMD, diet alone cannot approximate the levels of the supplements
used in this study.
Participants in this study were divided into four treatment groups
that received: 1) zinc alone; 2) antioxidants alone; 3) a combination
of antioxidants and zinc; or 4) a placebo, a harmless substance that
has no medical effect. The benefits were seen only in people who began
the study at high risk of developing advanced AMDthose with intermediate
AMD, and those with advanced AMD in one eye only. In this group, those
taking "antioxidants plus zinc" had the lowest risk of developing advanced
stages of AMD and its accompanying vision loss. Those in the "zinc alone"
group or "antioxidant alone" groups also reduced their risk of developing
advanced AMD, but at more moderate rates compared to the "antioxidant
plus zinc" group. Those in the placebo group had the highest risk of
developing advanced AMD.
There were 4,757 patients studied nationwide; 438 patients were studied
at the Emory Eye Center. The average length of study for each patient
at Emory was 6.5 years. Emory patients came from several Southeastern
states, including Florida, Georgia, Louisiana, South Carolina, North
Carolina, Tennessee and Texas. Patients at Emory were ages 60 to 80
and were equally represented by gender. Those with intermediate AMD
should check with their physicians before taking large doses of these
dietary supplements. Although the experience in this trial suggests
that these supplements were safe, there may be interactions with other
medications, discoloration of the skin, or anemia associated with taking
a large dosage of zinc.
"At Emory we are also looking at other compounds that may have a promising
effect in delaying the onset of macular degeneration," says Paul Sternberg,
Jr., M.D., director of the Vitreoretinal Surgery & Diseases section
at the Emory Eye Center. "AREDS is the first important step in developing
a therapeutic approach to dry macular degeneration. In our labs we are
studying several promising agents that may be even more effective. Down
the road, we look forward to future clinical trials that may provide
new answers to this disease."
Emory Eye Center Director Thomas M. Aaberg, Sr., M.D. says, "We are
very pleased to have been involved in this important study. The Emory
Eye Center’s pre-eminence in the field of ophthalmology is again demonstrated
with its inclusion in this important trial. We are the only AREDS clinical
trial center in the Southeast, and as such, we are pleased to help in
the fight to prevent blinding eye disease."
"These findings are only a part of what we will learn from AREDS about
macular degeneration. We will continue to answer many more questions
in the next five years as we continue to follow these patients," says