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Eye drops
used to lower elevated pressure inside the eye are also effective
in delaying the onset of primary open-angle glaucoma, according
to researchers.
Open-angle
glaucoma is a leading cause of blindness, and is the number
one cause of blindness in African Americans.
Fluid
normally flows into and out of the eye. Problems occur when
the fluid drains too slowly, building up and causing the pressure
in the eye to increase. When the pressure damages the optic
nerve, glaucoma and loss of vision occur.
"There
are several risk factors linked to the development of glaucoma,
and this study has helped us to define how much benefit we
can provide by decreasing eye pressure with eye drops,"
said Dr. Ronald L. Gross, professor of ophthalmology at Baylor
College of Medicine and co-author of the Ocular Hypertension
Treatment Study.
Researchers
evaluated 1,636 people, ages 40 to 80, with elevated eye pressure
but with no signs of glaucoma damage. Half of the participants
were given daily eye drops and the other half were not treated.
The participants who were given the eye drops had a drop in
eye pressure of approximately 20 percent, according to the
study published in the Archives of Ophthalmology.
The risk
for developing open-angle glaucoma was cut in half for the
participants who used the eye drops. A total of 4.4 percent
of the participants given eye drops developed glaucoma over
five years, while 9.5 percent who did not receive the drops
developed the condition. The participants with several risk
factors (age, race, family history, elevated eye pressure,
corneal thinness and anatomy characteristics of the optic
nerve) were found to be more likely to develop glaucoma.
Although
the drops were effective in reducing the rate of glaucoma,
not all patients with high eye pressure should automatically
receive treatment, according to Dr. Michael A. Kass, national
chair of the 22-center study and head of the Department of
Ophthalmology and Visual Sciences at Washington University
School of Medicine. Some of the drops cause side effects and
daily treatment can be inconvenient and expensive. Some patients
may prefer close observation rather than active treatment.
"Before
simply putting a patient on drops, doctors need to consider
the patient's general health status, their individual risk
factors and their life expectancy," said Kass. "It's
important to remember that even in the study group that did
not receive treatment, 90 percent of the people did not develop
glaucoma."
"Glaucoma
is often referred to as the 'sneak thief of sight' because
it often occurs with no pain or symptoms," said Gross.
"Many times patients don't notice a difference in peripheral
vision until the problem has progressed, therefore, it is
essential to visit an ophthalmologist to detect the condition
early."
Source:
Medical Week staff,
week of June 23, 2002
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