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Glaucoma is a condition where the
optic nerve is subject to damage--usually,
but not always, because of excessively
high intra-ocular pressure (pressure
within the eye--also called IOP).
If untreated, the optic nerve damage
results in progressive, permanent
vision loss, starting with unnoticeable
blind spots at the edges of the field
of vision, progressing to tunnel vision,
and then to blindness.
Glaucoma is actually a class of diseases--there
are at least twenty different forms
that can be divided into two categories:
open-angle glaucoma and narrow-angle
glaucoma. To understand what glaucoma
is and what these terms mean, it is
useful to understand eye structure.
Glaucoma occurs if the aqueous humor
is not removed rapidly enough or if
it is made too rapidly, causing pressure
to build-up. The high pressure distorts
the shape of the optic nerve and destroys
the nerve. Destroyed nerve cells result
in blind spots in places where the
image from the retina is not being
transmitted to the brain.
Open-angle glaucoma accounts for
over 90% of all cases. It is usually
chronic and progresses slowly. In
narrow-angle glaucoma, the angle where
aqueous fluid drainage occurs is narrow,
and therefore may drain slowly or
may be at risk of becoming closed.
A closed-angle glaucoma attack is
usually acute, occurring when the
drainage area is blocked. Glaucoma
is also a secondary condition of over
60 widely diverse diseases and can
also result from injury.
What causes Glaucoma?
The cause of eye damage in some otherwise
healthy eyes is a raised pressure
within the eye, (the intra-ocular
pressure), that can damage the nerve
over a period of time and this damage
results in poor blood supply or weak
end eye structure.
Some of the risk factors for Glaucoma
are:
- Persons who have had eye surgery or
an eye injury earlier in life.
- People with very near sightedness
or far sightedness.
- Diabetes and certain other chronic
diseases.
- African-Americans are more prone
to this condition.
- Anyone over the age of 60 are most
susceptible.
- People with a family history of
glaucoma.
- Persons with heart disease or conditions
resulting in sluggish blood flow to
the eye are at an increased risk for
developing glaucoma.
- Obesity has been identified as a
risk factor associated with glaucoma.
What are the likely symptoms of Glaucoma?
Glaucoma is an insidious disease
because it rarely causes symptoms,
however some glaucoma's do have signs
like :-
- Loss of side vision.
- Extreme eye pain and headaches.
- Difficulty in adjusting to a
dark room.
- Nausea and vomiting.
- Watering and increased sensitivity
to light, with appearance of halos
around lights.
- Blurring of vision.
- Need for frequent changes of
glasses.
How does one prevent Glaucoma?
Because glaucoma may not initially
result in symptoms, the best form
of prevention is to have regular eye
exams.
Patients with narrow angles should
avoid certain medications (even over-the-counter
medications, such as some cold or
allergy medications). Any person who
is glaucoma-susceptible (i.e. narrow
angles and borderline IOPs) should
read the warning labels on over-the-counter
medicines and inform their physicians
of products they are considering taking.
Steroids may also raise IOP, so patients
may need to be monitored more frequently
if it is necessary to use steroids.
Not enough is known about the underlying
mechanisms of glaucoma to prevent
the disease itself. However, prevention
of optic nerve damage from glaucoma
is essential and can be effectively
accomplished when the condition is
diagnosed and treated. As more is
learned about the genes that cause
glaucoma, it will become possible
to test DNA and identify potential
glaucoma victims, so they can be treated
even before their IOP becomes elevated.
What medications are used to treat
Glaucoma ?
Some of the medications prescribed
to treat Glaucoma include
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