Oogheelkundig Medisch Centrum Amsterdam

Age-Related Eye Disease Study (AREDS)

AREDS scientists found that people at high risk for developing advanced AMD - those with intermediate AMD, and those with advanced AMD in one eye only - reduced their risk of developing advanced stages of AMD by about 25 percent when treated with the combination of "antioxidants plus zinc." The "antioxidants plus zinc" supplement also reduced the risk of central vision loss by 19 percent in the same group. Participants at high risk for developing advanced AMD who were treated with "zinc alone" reduced their risk of developing advanced AMD by about 21 percent and their risk of vision loss by about 11 percent. Participants who were treated with "antioxidants alone" reduced their risk of developing advanced stages of AMD by about 17 percent and their risk of vision loss by about 10 percent.

The study was not designed to evaluate the effect of the supplements in study participants who initially had no AMD (Category One). This is because previous studies had indicated that people aged 60 and over with no AMD have a very low risk for developing a clear progression of AMD within a seven-year period (the life of the AREDS clinical trial). The Age-Related Eye Disease Study confirmed this low risk - participants with no AMD had less than a one percent chance of losing vision from AMD during the study.

For those study participants who initially had early AMD (Category Two), the antioxidants and zinc used by the AREDS researchers did not slow the disease's progression to intermediate AMD. Consequently, there is no apparent need for those diagnosed with early AMD to take the supplements studied in the AREDS. However, those with early AMD should get dilated eye examinations every year to determine if the disease is progressing.

Depending on their stages of AMD, the AREDS participants were placed in one of four categories. The one constant was that at least one eye of each participant had to be free from any vision-threatening eye disease other than AMD or cataract, and that eye could not have had previous surgery, except for cataract surgery. In Category One, participants had no AMD and a few small or no drusen - tiny yellow deposits in the retina - in either eye. In Category Two, participants had early AMD - either several small drusen or a few medium-sized drusen in one or both eyes. Category Three participants had intermediate AMD - either many medium-sized drusen or one or more large drusen in one or both eyes; these participants were at high risk for developing advanced AMD, which is generally defined as either a break-down of light-sensitive cells and supporting tissue in the central retinal area (advanced dry form), or abnormal and fragile blood vessels under the retina (wet form). Category Four participants already had advanced AMD in one eye, and in the other eye had good vision with no sign of advanced AMD. Previous studies had shown that the eye without AMD was at high risk for developing advanced AMD.

The participants in each category were randomly selected to receive daily oral tablets for one of four treatments: 1) zinc alone; 2) antioxidants alone; 3) a combination of antioxidants and zinc; or 4) a placebo, a harmless substance that looks like the real treatment but has no effect on eye disease. The antioxidant formulation contained a combination of vitamin C, vitamin E, and beta-carotene. The specific daily amounts of antioxidants and zinc used by the AREDS researchers were 500 milligrams of vitamin C; 400 IU of vitamin E; 15 milligrams of beta-carotene; 80 milligrams of zinc as zinc oxide; and two milligrams of copper as cupric oxide. In the study's planning stages, a panel of nutritionists, ophthalmologists, and biochemists reviewed the basic science and epidemiological data and recommended these vitamins and dosages.

On October 12, 2001, the National Eye Institute released the long awaited results of AREDS (Age-Related Eye Disease Study), designed to look at the effect of vitamin supplementation on AMD and cataracts. This multi-year research project involved almost 5,000 individuals 55-80 years old. They were divided into four groups according to their eye condition (no AMD, early AMD, intermediate AMD, advanced AMD). In each group, participants were randomly selected to receive daily tablets of either zinc alone, antioxidants alone, a combination of zinc and antioxidants, or a placebo (so-called sugar pill). About 90% of the participants remained in the study for five years.

The Encouraging Results

For people at high risk of developing advanced stages of AMD, use of the combination of antioxidants and zinc supplements reduced that risk by 25%.

For this same group, the risk of vision loss itself was reduced by 19%.

Study participants who had either no AMD or early AMD did not derive any apparent benefit from the supplements.

The vitamins also did not appear to have an effect on the development of cataracts.

The Supplement

The combined antioxidant/zinc supplement used in the study contained:

•Vitamin C - 500 milligrams

•Vitamin E 400 IU

•Beta-Carotene 15 milligrams

•Zinc (as zinc oxide) 80 milligrams

•Copper (as cupric oxide) 2 milligrams

Oogheelkundig Medisch Centrum Amsterdam