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| Glaucoma |
The most scary thing about glaucoma is that it can steal your vision gradually
and without your noticing. The best defense against glaucoma is a regular eye
examination. Glaucoma most often strikes people over age 50. But it is recommended
that during adult life everyone be tested at least every two years. Some people with glaucoma
do experience symptoms, but symptoms vary depending on the
type of glaucoma.
Primary
open-angle glaucoma
By far the most common type, primary open-angle glaucoma
develops gradually and painlessly. Since there are no early
warning signs, it can slowly destroy your vision without
your knowing it. The first indication may only occur after
some considerable vision loss.
Acute
angle-closure glaucoma
This results from a sudden blockage of the drainage channels
within your eye, causes a rapid build-up of pressure inside
your eye accompanied by blurred vision, the appearance
of colored rings around lights and sometimes extreme pain
or redness in the eyes.
What
is glaucoma?
The build-up of pressure inside your eye leads to glaucoma.
Aqueous fluid, which fills the space at the front of
the eye just behind the cornea, is made behind the iris
(the colored part of the eye) in the ciliary body. It
flows through the pupil (the dark hole in the center
of the iris), and drains from the 'anterior chamber angle,'
which is the junction between the edge of the iris and
the cornea. If this outflow of liquid is impaired at
all, there is a build-up of pressure inside the eye that
damages the optic nerve, which carries visual images
to the brain. The result is a loss of peripheral vision.
Thus, while glaucoma sufferers may be able to read the
smallest line on the vision test, they may find it difficult
to move around without bumping into things or to see
moving objects to the side.
What
causes glaucoma?
Some causes are known, others are not. Causes differ
depending on the type of glaucoma. The exact cause
of open-angle glaucoma, where the drainage channels
for the aqueous appear to be open and clear, is not
known. Closed-angle glaucoma can occur when the pupil
dilates or gets bigger and bunches the iris up around
its edge, blocking the drainage channel. An injury,
infection or tumor in or around the eye can also
cause internal eye pressure to rise either by blocking
drainage or displacing tissues and liquid within
the eye. A mature cataract also can push the iris
forward to block the drainage 'angle' between the
iris and the cornea. Glaucoma can occur secondarily
to a number of other conditions, such as diabetes,
or as a result of some medications for other conditions.
Who
gets glaucoma?
Glaucoma most frequently occurs after age 40, but
can occur at any age. If
you're of African heritage, you are more likely
to develop open-angle glaucoma -- and at an earlier
age -- than if you're Caucasian. Asians are more
likely to develop narrow-angle glaucoma. You
have a higher risk of developing glaucoma if a
close family member has it or if you have high
blood pressure or high blood sugar (diabetes).
There is also a greater tendency for glaucoma to
develop in individuals who are nearsighted. Those
at heightened risk for glaucoma should have their
eyes checked at least once a year.
Why
is glaucoma harmful to vision?
The optic nerve, located at the back of
the eye, carries visual information to
the brain. As the fibers that make up the
optic nerve are damaged by glaucoma, the
amount and quality of information sent
to the brain decreases and a loss of vision
occurs.
Will
I go blind from glaucoma?
If diagnosed at an early stage, glaucoma
can be controlled and little or no
further vision loss should occur. If
left untreated, side awareness (peripheral
vision) and central vision will be
destroyed and blindness may occur.
How
is glaucoma detected?
Tests for glaucoma are part of
a comprehensive eye examination.
A simple and painless procedure
called tonometry measures the internal
pressure of your eye. Ophthalmoscopy
examines the back of the eye to
observe the health of the optic
nerve. A visual field test, a very
sensitive test that checks for
the development of abnormal blind
spots, may also be completed.
How
is glaucoma treated?
Glaucoma is usually treated
with prescription eye drops
and medicines. In some cases,
surgery may be required to
improve drainage. The goal
of the treatment is to prevent
loss of vision by lowering
the pressure in the eye.
Will
my vision be restored after
treatment?
Unfortunately, any vision
loss as a result of glaucoma
is permanent and cannot
be restored. This is why
regular eye examinations
are important. Glaucoma cannot be prevented,
but early detection and treatment can control glaucoma and
reduce the chances of damage to the eye and a loss of sight. |
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