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Questions:
- What is glaucoma?
- Who is affected by glaucoma?
- What are the warning signs of glaucoma?
- How is glaucoma detected, and what is the treatment?
- What research is underway at The Schepens Eye Research
Institute?
Glaucoma affects over 3 million Americans and is the second leading
cause of blindness in the elderly in the United States. The disease begins when a
blockage at the front of the eye prevents the aqueous humor, the clear fluid that
flows through the eye's front chamber, from exiting the eye. The result is a build-up
of pressure that ultimately damages the delicate fibers of the optic nerve, which
connects the eye with the brain. The vision loss caused by glaucoma is irreversible.
It is a puzzling disease with many forms, which makes the search for a cure even
more challenging.
There are two basic forms of glaucoma, open- and closed-angle. In
open-angle glaucoma, the "angle" of the anterior chamber, where the cornea meets
the iris at the front of the eye, appears to be open. This allows the aqueous humor
to flow through the sieve-like trabecular meshwork, which filters debris from the
fluid. Deep within this tissue, however, an abnormality impedes the fluid flow out
of the eye. The form of the disease known as primary open-angle glaucoma (POAG) is
what most people think of as "glaucoma." POAG is the most common form of the disease,
accounting for up to 80% of all cases of glaucoma in the U.S. Glaucoma is primary
if the cause is not known and not obviously related to another eye disease. If glaucoma
is caused by some other known problem, it is secondary.
POAG is characterized by elevated intraocular pressure (IOP), optic
nerve damage, and visual field defects. The patient may experience blurred vision
or a gradual vision loss, and the disease usually travels a chronic, insidious course
over many years. Symptoms may not be evident until the later stages, making POAG
the most difficult form of glaucoma to diagnose.
In closed-angle glaucoma, an anatomical abnormality pushes the iris
forward, blocking both the angle and access of the fluid to the filtering tissue.
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About 3 million Americans have open-angle glaucoma - but half
of them may not be aware of it. Glaucoma is the leading cause of blindness for African-Americans
in the U.S. They are five times more likely to develop it than whites, due to inherited
risk factors. African-Americans over 40 and people in other ethnic groups over 60
are at greatest risk for developing glaucoma.
Glaucoma is a leading cause of blindness in part because it has no symptoms
in early stages to alert the patient to the disease. As the disease advances, there
is blurred vision or a gradual loss of peripheral (side) vision -- by this point, although
treatment can control the disease, the lost vision cannot be restored.
Fortunately, early stage glaucoma can be detected with a simple,
painless test. The ophthalmologist measures the patient's IOP level with a special
device called a tonometer. Changes in the optic nerve are examined with an ophthalmoscope
that enables the physician to look through the pupil to see the back of the eye.
Treatment begins if there is noticeable damage to the optic nerve, or if the opthalmologist
feels the patient's IOP is high enough to pose a threat to the optic nerve.
Glaucoma treatment can involve three stages. The first step is drug
therapy, which often is an effective way of lowering the IOP and thus controlling
the disease.
If this does not work, laser treatment may be tried to open channels
for fluid to escape. Laser therapy is relatively painless and is usually performed
in the physician's office in two sessions over the course of a month. Some patients
may require additional laser treatments or a third form of treatment, filtration
surgery. During this procedure, the physician surgically creates a valve in the wall
of the eye using existing eye tissue, allowing the aqueous humor to drain. This therapy,
combined with close follow-up, can halt the progression of glaucoma.
Until there is a cure for glaucoma, the best weapon against this potentially
blinding disease is early detection, leading to a well-planned course of treatment.
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Accomplishments
- Developed new techniques to study the outflow channels through
which aqueous humor escapes from the eye
- Uncovered new information about the mechanism by
which the optic nerve damage occurs
- Played a vital role in the development
of new medication and improved surgical treatment of
glaucoma
- Improved
current techniques for
operating on cases of
glaucoma that resist
medical treatment.
Current Research
- Continued study of how the optic nerve is damaged by glaucoma.
- Investigation of why African -Americans and other
minorities are much more susceptible to glaucoma damage.
- Continued study of how the outflow channels
of the eye become obstructed, thereby causing glaucoma.
* Content provided by THE
SCHEPENS EYE RESEARCH INSTITUTE |
Adaptive Technology, a division of Perkins Products 
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