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Our eyes contain a clear fluid called aqueous humor, which is
continually produced by the eye to bathe and nourish the structures inside it.
This fluid normally drains out of the eye through a series of drainage canals in
a fine meshwork located around the edge of the iris (the colored part of the eye
that surrounds the pupil). This fluid system should not be confused with tears,
which are produced outside of the eye and are not related to glaucoma. In people
with glaucoma, the fluid fails to drain, as it should, increasing the pressure
inside the eye.
It
might help to understand it if you think of a spring-fed lake with a stream
running out at one end. The spring continually pumps water into the lake, and it
drains through the stream, keeping the lake level balanced. If, for some reason,
the stream becomes blocked or its opening narrows to the point that water can no
longer run out freely, the water in the lake will rise. That is similar to what
happens in glaucoma.
Fluid
continues to be produced by the eye but is unable to flow freely out. As a
result, the
restricted fluid flow can cause a buildup of fluid and an increase
in the pressure inside the eye called increased Intraocular pressure (IOP). In
time, this increased pressure may damage the optic nerve at the back of the eye,
which can cause loss of vision. If the nerve and in some cases, eventually lead
to total blindness. Doctors have had significant success in treating and
controlling glaucoma through the consistent use of medicine to lower the
pressure in the eye.
Although there are other forms of glaucoma, open-angle
glaucoma is by far the most common form however, it is believed to develop
because the eye’s drainage canals gradually, over time, become partially clogged
or obstructed. The entrance to the canal appears open (hence the name), but
further downstream, something is blocking the free flow of the fluid out of the
eye. People with this type of glaucoma usually have no symptoms at first and
seldom notice any change in their vision. Doctors discover it during an eye exam
when they measure the pressure of the eye and examine the optic nerve in the
back of the eye with a light scope. Generally, this type of glaucoma progresses
very slowly and is usually treated with medicine. It is important to note,
however, that control of your condition is greatly dependent on your faithfully
following your treatment instructions. If not treated, the risk of high
Intraocular pressure causing progressive damage to the optic nerve increases.
This can gradually reduce your field of vision - starting with loss of
peripheral, or side, vision. Ultimately, this loss of vision can extend to
larger areas of vision and may lead to total blindness. The status of your
condition will be monitored by color photography of the optic nerve head, visual
field analysis and
retinal tomography.
What Factors Lead to Glaucoma? People of all ages can get
glaucoma, but it is more commonly diagnosed in those who are over 55 years old,
highly nearsighted, or diabetic. The tendency to develop glaucoma may be
inherited. Also, if you are of African ancestry, your chance of having glaucoma
is significantly greater. Having multiple risk factors increases your chance of
developing glaucoma. However, people without these
risk factors can still get
glaucoma. Doctors and researchers do not know what causes this condition; they
do know, however, that it is not caused by reading too much or in poor light,
improper nutrition, or wearing contact lenses.
How Is It Treated? Open-angle glaucoma is treated effectively
with medicine, usually in the form of eye drops. Some eye drops reduce pressure
in the eye by making the eye produce less fluid. Less fluid flowing into the eye
reduces the pressure. Other eye drops lower pressure by improving the drainage
of fluid through the blocked drainage canals. Some patients may eventually need
surgery if medicine does not control their glaucoma.
* Please consult your eye doctor for further details. This
information is presented for informational purposes and is not designed to
substitute for the advice of your eye doctor.
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