A
Visual Crossroads
by Nathan
Johnson
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One
word inevitably
seems to come up when discussing age-related macular degeneration
with those working on a cure-frustration. This debilitating
eye disease, the number one cause of blindness among the elderly,
affects millions of people in the U.S. alone. While a whole
slough of preventative 'treatments' exist, from vitamin supplements
to laser therapy, most ophthalmologists agree that macular degeneration
is a doozy. There
are two types of age-related macular degeneration-dry and wet.
The former is essentially a breakdown of cells in the macula,
a sensitive layer of tissue at the core of the retina. This
form of the disease, the less severe of the two, has no treatment
at all. The latter form of macular degeneration is much more
serious. It involves an abnormal formation of blood vessels
(technically called neovascular membranes) behind the retina.
These little vessels wreak havoc at the heart of the retina
by leaking onto the macula, and eventually causing a total clouding
of a person's central vision. The one bright side to wet macular
degeneration is that a number of treatments exist to slow or
even halt its spread.
Traditional
Treatments and Rehabilitation
"Many
people can lead normal lives with the appropriate treatment
and the appropriate vision rehabilitation," says Abdhish R.
Bhavsar, MD, a clinical professor at the University of Minnesota
and attending surgeon at the Phillips Eye Institute in Minneapolis.
"Vision rehabilitation involves . . . utilizing the vision
that people have remaining and helping them avoid looking
into the areas that have the blind spots . . . so, in effect,
they look around the blind spot."
In
order to prevent the spread of macular degeneration, doctors
also prescribe a number of treatments at the first signs of
this disease. These range from wearing sunglasses to block
out potentially harmful ultraviolet rays to taking one of
the many 'eye-intensive' vitamin supplements currently on
the market. However, because preventing macular degeneration
is such an iffy proposition, many doctors let their patients
decide what preventative steps to take.
Doctors
Caution
Age-related
macular degeneration is technically untreatable-there is no
cure. "Some studies have shown (that some treatments) can slow
down macular degeneration," says Colorado physician Mark Walker,
MD. "Unfortunately," he continues, "most of the preventative
things out right now are not proven." Even the most state-of-the-art
treatments focus solely on stopping the spread of this wearisome
disease. And while these treatments are definitely a step in
the right direction, doctors shy away from being too optimistic.
For
starters, only the more serious form of this disease--wet macular
degeneration--can be treated; and even then these treatments
only work like a hose putting out a spreading wildfire. One
of these treatments, called PDT, or Photodynamic Therapy, effectively
zaps the blood vessels growing behind the retina. "When they
say that (wet macular degeneration) is treatable, what they
mean is that they can do laser therapy to try and stop new vessels
from growing," says Dr. Walker. PDT, like other treatments
for macular degeneration, cannot reverse the damage that has
already been done.
Light
at the end of the tunnel?
Recent
developments in the war against Macular Degeneration may give
doctors, and their patients, reason to lift an eye.
On
April 12, the Food and Drug Administration gave the go-ahead
for the release of a promising new remedy. In clinical trials,
Visudyne, a light-triggered drug manufactured by Canadian
based QLT PhotoTherapeutics, helped stop the formation of
the blood vessels responsible for the damage that comes along
with wet macular degeneration.
How
does Visudyne work? First, through an injection in the arm,
Visudyne travels to the abnormal blood vessels developing
around the macula. A beam is then directed toward these vessels,
activating the drug and preventing further growth. This minimizes
the degree to which central vision becomes clouded. Researchers
claim that about 30 percent of patients who suffer from this
symptom are potential candidates for Visudyne. Unfortunately,
doctors once again stop short of total optimism. According
to published reports, Visudyne is not a cure for age-related
macular degeneration. On the other hand, it could be the
most promising development in years.
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