Age-Related Macular Degeneration (AMD)
Macular degeneration is the most common cause of legal blindness in developed countries and affects up to 1 in 10 patients over the age of 60 in the United States. Macular degeneration affects the central portion of the retina, the layer of tissue which detects light and lines the inner surface of the eye (similar to the film of a camera). As the disease progresses, the central portion of the retina is damaged, and results in a decrease in the central vision (see simulated photo,below).
Simulation of the distorted central vision of a patient
with macular degeneration.
Damage to the retina can be
seen by your eye doctor in the form of yellowish deposits
in the retina (drusen) in the early form of the disease and
by atrophy (or cell death) as the macular degeneration
progresses.
Picture of the retina of a patient with macular
degeneration. Notice the yellowish deposits (drusen) in the
center of the picture.
About 10% of patients develop
blood vessel growth (neovascularization) underneath the
retina, which can lead to a precipitous drop in vision.
This is called the "wet" form of AMD. In some of these
patients, the use of a laser to destroy the abnormal blood
vessels can help stabilize the vision.
The vast majority of patients with macular degeneration
have the "dry" form of AMD, in which the progression of
disease is slow and is related to a gradual cellular death
in the central retina (atrophy). Until recently, there was
no scientifically proven treatment for these patients.
However, a recent study (the Age-Related Eye Disease Study,
or AREDS) funded by the National Eye Institute revealed that
daily supplementation with vitamins A, C, E, and zinc
delayed the progression of macular degeneration.
Specifically, almost 4000 patients with mild,
intermediate, or advanced AMD were enrolled in the study
and followed for an average of more than 6 years.
Patients were randomly assigned to receive daily oral
tablets containing 1) high doses of antioxidants
(vitamins A, C, and E); 2) zinc; 3) antioxidants plus
zinc; or 4) placebo. In patients with intermediate or
advanced forms of macular degeneration, supplementation
with antioxidants plus zinc decreased their risk for
advancement by 25% over the follow-up period! More
details of the results of this study can be seen here.
Based on this study, Boulder
Eye Surgeons recommends that all patients with intermediate
or advanced forms of macular degeneration take oral vitamin
and zinc supplementation at the dosages used in the study
(see below). Bausch and Lomb provided the vitamins used in
the study and a new product, Ocuvite® PreserVision™, supplies the
exact vitamin formulation used in the AREDS study.
Other brands can be used, but
be sure that they contain the following vitamins and zinc
in the dosages indicated: vitamin C, 500 mg; vitamin E, 400
IU; beta carotene, 15mg; zinc, 80 mg, as zinc oxide; and
copper, 2 mg, as cupric oxide. Smokers should be careful
taking high dosages of vitamin A, as some studies have
shown this to increase mortality rates.
You can monitor your central vision for the progression of
macular degeneration using an Amsler grid (see below). A
rapid change in the central distortion of your vision may
indicate the "wet" form of macular degeneration (see above)
which may be amenable to laser treatment. The Amsler grid
test consists of a grid of lines. The grid should be held
about 12 inches from the eyes and each eye should be tested
independently. While looking at the central dot with each
eye separately, be sure that you can see all four corners
of the grid. If not, or if any of the lines are blurry,
wavy, distorted, bent, gray, or missing, you should call
Boulder Eye Surgeons to have your eyes examined. We
recommend using the grid at least once a week. You can
remind yourself of this by placing the grid in a convenient
place (i.e. on the refrigerator door or bathroom mirror).
Use the grid below to take the test on your computer
screen. Or, you can download the black-on-white version
for printing.
