Age related macular degeneration (AMD) is one of the most common causes
of poor vision after age 60. Although the specific cause is unknown,
AMD seems to be part of aging. While age is the most significant risk
factor for developing AMD, heredity, blue eyes, high blood pressure,
cardiovascular disease, and smoking have also been identified as risk
factors. AMD accounts for 90 percent of new legal blindness in the US.
Nine out of 10 people who have AMD have the dry form, which results in
thinning of the macula, the area of the retina responsible for central
vision. Dry AMD takes many years to develop. Currently there is no
treatment.
The wet form of AMD occurs much less frequently (one out of 10 people) but is more serious.
Laser surgery is the only proven effective treatment, to date, for wet
AMD. The procedure usually does not improve vision but prevents further
loss of vision.
The visual symptoms of AMD involve loss of central vision. While
peripheral vision is unaffected, one loses the sharp, straight-ahead
vision necessary for driving, reading, recognizing faces, and generally
looking at detail. Imagine being able to see a clock on the wall but
unable to make out the time or unable to read because you could not see
parts of words on the page.
Promising AMD research is being done on many fronts. In the meantime,
high-intensity reading lamps, magnifiers and other low-vision aids help
people with AMD make the most of remaining vision.
Macular Degeneration and Nutrition
Both doctors and the public have shown growing interest
in the relationship between diet and health. Good nutrition depends on
a healthy mixture of proteins, carbohydrates, fats, vitamins and
minerals. Protein is needed for the building blocks and chemical
machinery of our bodies; carbohydrates are needed for immediate fuel
and energy; fats are needed for long term storage of fuel and energy.
Vitamins are organic compounds that our bodies cannot manufacture but
are essential for maintaining good health. The eye, like any other part
of the body, benefits from a healthy diet. Although the exact causes of
macular degeneration are not understood, there is some evidence that
vitamins and minerals may play a preventive role.
Macular degeneration is damage or breakdown of the macula, the small
part of the retina responsible for central vision. It affects both
distance and close vision and can make some activities–like threading a
needle or reading–very difficult or impossible. Macular degeneration
is the leading cause of severe visual loss in people over 65.
Zinc, one of the most common minerals in our body, is very concentrated
in the eye, particularly in the retina and macula. Zinc is necessary
for the action of over 100 enzymes, including chemical reactions in the
retina. Studies show some older people have low levels of zinc in their
blood. Because zinc is important for the health of the macula, some
think that supplements of zinc in the diet may slow down the process of
macular degeneration. Scientific studies are not complete and there is
no agreement concerning the value of zinc supplements. It is possible
that too much zinc may interfere with other trace minerals such as
copper.
Normal chemical reactions from light in the eye activate oxygen that
may cause macular damage. Some vitamins function as antioxidants that
work against this activated oxygen. It may be claimed that antioxidant
vitamins (vitamins A, C and E) can help slow down macular degeneration
and other aging problems. As in the controversy over zinc, there is no
agreement that these antioxidants actually help macular degeneration.
The first step to overall good health is a balanced diet. Vitamins and
minerals are commonly given as supplements to the diet in amounts
determined by recommended daily allowances. These supplementary dosages
cause no apparent harm and are commonly available. Large doses of
vitamins, called therapeutic doses, in amounts many times the
recommended daily allowances, may not be completely safe.
Nutrition and macular degeneration is still being researched.
Consultation with your ophthalmologist before beginning to take
therapeutic doses of any vitamin or mineral is advisable.
