Mardella Richey (right) talks with Dr. Emily Chew, deputy director of the Division of Epidemiology and Clinical Research at NEI, before an eye exam at the NIH Clinical Center. Richey participated in the first Age-Related Eye Disease Study, and Dr. Chew was lead investigator for that study as well as a new study involving the role of different nutritional factors in eye health.
Photo courtesy of NIH/NEI
"I don't recognize people unless I'm almost nose to nose," says Mardella Richey. "When I go out to dinner, restaurants are so dark I wouldn't recognize my own mother." Even a daily task like cooking can be a problem. "I can't read what it says on the bottle—if it's curry powder or celery powder," says Richey, who recently confused one for the other when making tomato soup. (The curried soup wasn't bad!)
Richey is among some nine million Americans with agerelated macular degeneration (AMD), the leading cause of vision loss for people over 60. AMD destroys sharp central vision, which is necessary for seeing objects clearly and for common daily tasks such as reading and driving.
Nearly two million people have the advanced form of the disease, called wet AMD, which can cause rapid vision loss in both eyes. An early symptom of wet AMD is that straight lines may appear wavy and distorted, and images on TV may appear blurry. It is caused when abnormal blood vessels grow beneath the retina and leak blood and fluid under the macula, the small area near the center of the retina responsible for central vision.
Initial study encouraging
Richey participated in the Age-Related Eye Disease Study (AREDS), a nationwide clinical trial launched by the National Eye Institute (NEI) in 1992, results from which were published in 2001. The AREDS study showed that an experimental combination of three anti-oxidant vitamins (C, E and beta carotene) and the minerals zinc and copper reduced the risk of progressing to advanced AMD by 25 percent and the risk of moderate vision loss by 19 percent.
Says AREDS lead investigator Emily Chew, M.D., deputy director of NEI's Division of Epidemiology and Clinical Research, "The results were of public health significance. About seven million people are at risk of developing AMD in the next five years, so you could reduce the risk of developing advanced AMD and its accompanying vision loss by 300,000 people if all seven million took the AREDS supplement. That's pretty big savings in health care and productivity."
Foods Lower AMD Risk
As a follow-up to AREDS, last October, in partnership with nearly 100 clinical centers nationwide, NEI began AREDS2, a study to determine how high doses of anti-oxidant and fish oil supplements affect the risk of advanced AMD, the need for cataract surgery, and moderate vision loss. Four thousand participants between the ages of 50 and 85 who have AMD are being sought for the study. The trial is "double-masked," meaning neither investigators nor participants know who is getting which combinations of the anti-oxidants and supplements or a placebo.
From earlier studies, NEI researchers knew that adults eating kale, mustard greens, collard greens, and raw or cooked spinach (vegetables high in lutein and zeaxanthin, two anti-oxidants from the same family as beta carotene), were at considerably less risk of developing advanced AMD than those who didn't. And adults consuming more sources of the omega-3 fatty acids DHA and EPA (found in fish, especially salmon) also appeared to be at less risk.
Over the next five years, researchers will be testing the effects of the two kinds of nutrients – the vegetablederived vitamins lutein and zeaxanthin, and the fatty acids DHA and EPA – in four participant groups. One group is to receive lutein and zeaxanthin supplements; one will get DHA and EPA; one will get both the vitamins and the fatty acids; and a fourth (control) group will get a placebo.
All participants will be given the choice of also taking the initial AREDS combination of vitamins (C, E, and beta carotene) and minerals (zinc and copper). They may also instead choose to participate in a second part of the study in which the original AREDS formulation will be further tested by eliminating beta carotene and/ or reducing the amount of zinc.
For more information about the participating clinics and/or to enroll in the AREDS2 study, call 1-877-273-3780 or look online at www.nei.nih.gov/AREDS2.
Pat McNees is a freelance medical writer and editor.
What Is Macular Degeneration?
(Left) Normal vision, (right) macular degeneration
- In "dry" macular degeneration, small yellowish deposits known as drusen form under the retina, affecting the macula, the small area near the center of the retina that helps produce the sharp central vision needed for reading or driving.
- In "wet" macular degeneration, blood vessels growing up from below the retina leak blood under the retina. Pressure from these pockets of blood damage the light-sensing cells, destroying the ability to see straight ahead.
"Symptoms of AMD don't usually start until the 60s or later," says study chair Dr. Emily Chew of the National Eye Institute. "But you get signs in the 50s. In some cases, where it's genetic, you can get them younger than that."
Advances in Macular Degeneration Research
On June 30, of last year, the Food and Drug Administration (FDA) approved a promising new drug—ranibizumab (marketed as Lucentis) — for treatment of neovascular agerelated macular degeneration (AMD). Though the neovascular form of AMD represents only about 10 percent of AMD cases, it is the form that causes most vision loss.
Now, a similar drug—bevacizumab (marketed as Avastin) — from the same manufacturer is also being used successfully by many ophthalmologists to treat AMD. This second drug is currently only FDA-approved for treatment of matastatic cancer, but ophthalmologists continue to use it "off-label" (not yet officially approved) for AMD treatment. The second drug is considerably cheaper for patients than ranibizumab.
"The good news for patients is that there are two new medications for neovascular age-related macular degeneration, both of which appear to work better than the alternatives," stated Robert Steinbrook, M.D., in the October 5, 2006, issue of The New England Journal of Medicine. " But since they have never been directly compared, physicians can only speculate about which drug is superior with regard to safety, efficacy, and frequency of administration."