Glaucoma
Glaucoma is a disease which damages the optic nerve, the
nerve of sight. It affects approximately two percent of the population,
slowly and permanently taking away vision. Glaucoma can be inherited and
it certainly is more prevalent in the elderly. Most cases do not
have symptoms or warning sings.
The visual loss associated with glaucoma typically begins with the "side
vision" (also called peripheral vision) and this loss is not
noticeable to patients even in very advances stages. A complete eye examination
including a pressure check is required to diagnose glaucoma. This is one
of many reasons the American Academy of Ophthalmology recommends yearly
eye exams for anyone over 65 years old. Undetected and insufficiently
treated glaucoma can result in blindness.
If glaucoma is suspected on examination, a visual
field test should be performed to evaluate the peripheral vision.
It is also extremely important for your eye care specialist to look at
the optic nerve and the trabecular meshwork (the area where fluid normally
drains out of the eye). Thus, your eye physician does much more than simply
check the eye pressure when evaluating glaucoma.
 New
scanning laser technology can help in the early detection of glaucoma.
The Heidelberg Retinal Tomographer
(HRT) uses a laser to obtain a three dimensional image of the optic nerve
(unlike a two dimensional photograph of the optic nerve surface). This
data can be compared to a normal population and thus help us detect early
abnormalities in the optic nerve which often precede the visual field
loss caused by the glaucoma. The HRT optic nerve analyzer is located in
our Parkersburg office.
Early detection of glaucoma is also enhance by the use of Blue-Yellow
visual field testing. This Short Wave Automated Perimetry (SWAP)
differs from standard perimetry only in that a carefully chosen wavelength
of blue light is used as the stimulus, and a specific color and brightness
of yellow light is used for the background illumination. Other than these
wavelength specifications, the test is very similar to standard visual
field tests. Visual field defects with blue-yellow can be an early indicator
of impending glaucomatous visual field loss not yet detected by standard
white-on-white fields. Patients who have eye pressures higher than normal,
for example, may show visual field defects earlier with the blue-yellow
field than standard white-on-white fields. This new field machine is available
in our Parkersburg office.
 Glaucoma
is most commonly treated with eye drops designed to lower the eye pressure.
Treatment is typically life long as when the drops are discontinued the
pressure returns to the higher level. There are several different types
of eye drops used to treat glaucoma. Beta-blockers (such as Timoptic and
Betoptic) are among the most commonly used. New types of eye drops have
recently been developed that have proven helpful to many patients not
adequately controlled on their current medications. Some of the newer
generation glaucoma drugs include Iopidine, Alphagan, Trusopt, and Xalatan
(pronounced Zy-lah-tan) The most recent developments are Rescula,
Lumigan and Travatan. These new drugs lower eye pressure by mechanisms
different than previously available drugs. They often work well in combination
with some of the more longstanding medications such as beta-blocker eye
drops.
Treatment must be individualized as many patients have
medical problems such as heart or lung disease and Beta-blockers can cause
problems for such patients. Additionally, one type of drop may work better
than another for any given individual. Your eye physician's goal is to
treat the glaucoma patient with the most effective drop without causing
unwanted side effects from the medications.
Laser surgery can be performed when eye drops alone do not
adequately lower the eye pressure. Laser surgery can often be done in
the office and it does not have any physical restrictions. Selective
Laser Trabeculoplasty, SLT, is one of the greatest new advances for
treatment of open angle glaucoma. This laser can be applied in a few minutes
to lower eye pressure and treat glaucoma. Eye pressure is lowered in about
70% of the patients treated. The lower eye pressure is believed to help
prevent further glaucoma damage to the optic nerve. Many patients can
reduce or even eliminate their dependency on drops by having this laser
applied.
In advanced glaucoma when medications and/or laser surgery
are unable to lower the eye pressure to a safe level, it may become necessary
to perform a surgical procedure in the operating room call a trabeculectomy.
This procedure creates a new "trap door" passage for fluid to
drain out of the eye. This alternate route for drainage lowers the eye
pressure. New surgical techniques utilize a medication called Mitomycin
C which is applied to the surgical site during the operation. The Mitomycin
helps improve the success rate of the surgery in cases that carry a greater
risk for failure.
The most important thing to remember from this article
is that THERE ARE NO SYMPTOMS OR EARLY WARNING SIGNS FOR CHRONIC GLAUCOMA.
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Glaucoma Testing
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