Routine
Eye Exams Help Find Glaucoma Early
New
Medications Offer Early Treatment Options
It is called the silent
thief of sight, and for good reason.
Glaucoma has few if
any early symptoms. And when they do appear, the disease has
already robbed its victims of some sight. About 3 million Americans
have glaucoma, but many do not know it yet.
Regular, routine eye exams,
including special tests, can improve the odds of early detection, experts
say. And, once detected, the disease can be controlled - and remaining
vision preserved - with improved medications and surgery techniques.
"The key is to get
checked before the disease becomes symptomatic, " says Dr. Andrew
Iwach, an ophthalmologist at the University of California San
Francisco.
Since glaucoma risk
rises with age, eyes should be tested at about age 35 and 40,
then every two to four years after age 40 and every one to two
years after age 60, suggests the Glaucoma Research Foundation.
Those at high risk due to family history should be examined
every one to two years after age 35.
Glaucoma
Causes Vision Loss
Glaucoma is actually
a group of eye diseases, but all types damage the optic nerve,
causing vision loss and, sometimes, blindness. The optic nerve
connects the retina to the brain and it houses more than 1 million
nerve fibers.
For good vision, a
person needs a healthy optic nerve.
What goes wrong in glaucoma? In the front of the eye, clear
fluid flows in and out of a space called the anterior chamber.
When the fluid passes
out too slowly and builds up, pressure can increase and this
intraocular pressure can rise to the point where it damages
the optic nerve. This form of the disease, the most common,
is called open angle glaucoma.
It is so named
because the fluid leaves the anterior chamber at the open angle
where the cornea and the iris meet.
Some people have glaucoma,
and optic nerve damage, even without the pressure within the
eye rising - a type called low-tension or normal-tension glaucoma.
And, in recent years,
Dr. Iwach says, experts have discovered the thickness of the
cornea somehow plays a role in who gets glaucoma.
"We may have a patient
who has a higher than normal pressure, but the optic nerve looks
fine," he says. Odds are the patient has a thick cornea, somehow
possibly protecting against damage to the nerve.
During an exam for
glaucoma, physicians will also look at the optic nerve,
measure the intraocular pressure and evaluate peripheral vision
- often affected first in glaucoma. To lower the pressure inside
the eye, drops are commonly prescribed.
Newer
Treatments Give Hope
"Twenty years ago,
in order to control glaucoma, we needed to use drops four times
a day," says Dr. Michael Berlin, a professor of clinical ophthalmology
at the Jules Stein Eye Institute at the UCLA David Geffen School
of Medicine.
Some of the newer
eyedrop medications only need to be taken once or twice a day.
Drops work either by causing the eye to make less fluid or helping
the fluid drain.
If surgery is deemed
the best treatment, a physician may perform a procedure
called a laser trabeculoplasty. This procedure involves
a laser aimed at the lens of the eye and makes several evenly
spaced burns, stretching the drainage holes inside the eye and
allowing the fluid to drain more effectively.
While the traditional
approach has been to use medications first, then surgery if
the glaucoma still progresses, Dr. Iwach says the latest thinking
has it that some patients may benefit most from having surgery
first.
Compliance with medication
is a problem among patients, Drs. Berlin and Iwach agree.
"Most patients are
not compliant," Dr. Berlin says. Part of the reason, he suspects,
is the patient can tell little difference in vision during the
short term, whether he takes the medicine or not.
Good patient-physician
communication is the key. All the latest information - whether
medication or laser therapy is best; which eye drops are preferred
- "has to be customized to the individual patient," Dr. Iwach
says.
Always consult your
physician for more information.
Online
Resources
(Our Organization
is not responsible for the content of Internet sites.)
American
Academy of Ophthalmology
Centers
for Disease Control and Prevention (CDC)
Glaucoma
Research Foundation
National
Eye Institute
National
Institutes of Health (NIH)
Prevent
Blindness America
US
Department of Heath and Human Services
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February 2004
Routine
Eye Exams Help Find Glaucoma Early
Newer
Treatments Give Hope
Facts
About Glaucoma
Online
Resources
Facts
About Glaucoma
According to the National
Eye Institute, glaucoma is detected through a comprehensive
eye exam that includes:
Visual acuity
test. This eye chart test measures how well you see
at various distances.
Visual field test. This test measures your
side (peripheral) vision. It helps your eye care professional
tell if you have lost side vision, a sign of glaucoma.
Dilated eye exam. Drops are placed in your
eyes to widen, or dilate, the pupils. Your eye care professional
uses a special magnifying lens to examine your retina and optic
nerve for signs of damage and other eye problems.
Tonometry.
An instrument measures the pressure inside the eye. Numbing
drops may be applied to your eye for this test.
Pachymetry. A numbing drop is applied to your
eye. Your eye care professional uses an ultrasonic wave instrument
to measure the thickness of your cornea.
There is no cure for
glaucoma. Vision lost from the disease cannot be restored.
However, immediate
treatment for early stage, open-angle glaucoma can delay progression
of the disease. That is why early diagnosis is very important.
Treatment may include:
Medications.
Medications in the form of eyedrops or pills, are the most common
early treatment for glaucoma. Some medications cause the eye
to make less fluid. Others lower pressure by helping fluid drain
from the eye.
Glaucoma medications
may be taken several times a day. Most people have no problems.
However, some medications can cause headaches or other
side effects. For example, drops may cause stinging, burning,
and redness in the eyes.
Because glaucoma often
has no symptoms, people may be tempted to stop taking, or may
forget to take, their medications. You need to use the drops
or pills as long as they help control your eye pressure. Regular
use is very important.
Laser trabeculoplasty.
Laser trabeculoplasty helps fluid drain out of the eye. Your physician
may suggest this step at any time. In many cases, you need to
keep taking glaucoma medications after this procedure.
Laser trabeculoplasty
is performed in your physician's office or eye clinic. Before
the surgery, numbing drops will be applied to your eye. As you
sit facing the laser machine, your physician will hold
a special lens to your eye.
A high-intensity beam
of light is aimed at the lens and reflected onto the meshwork
inside your eye. The laser makes several evenly spaced burns
that stretch the drainage holes in the meshwork. This allows
the fluid to drain better.
Your physician
may give you some drops to take home for any soreness or inflammation
inside the eye. You need to make several followup visits to
have your eye pressure monitored.
Conventional
surgery. Conventional surgery makes a new opening for
the fluid to leave the eye. Your physician may suggest
this treatment at any time. Conventional surgery often is done
after medications and laser surgery have failed to control pressure.
A small piece of tissue
is removed to create a new channel for the fluid to drain from
the eye.
For several weeks
after the surgery, you must put drops in the eye to fight infection
and inflammation. These drops will be different from those you
may have been using before surgery.
Always consult your
physician for more information.
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