Advances in Treating Glaucoma
by Robert Arleo,
Eighty thousand Americans lose their sight to glaucoma every year, while ten
times that number struggle with glaucoma-related vision problems. A disease of
the optic nerve, glaucoma is the most prevalent major eye disorder in people
over the age of 60.
Glaucoma occurs when pressure inside the eye becomes gradually elevated,
causing damage to the optic nerve. Most people have no symptoms until they
notice changes in their visual field-typically a decrease in their peripheral
vision. Unfortunately, at this point, damage to the optic nerve is well
underway. There is no cure for glaucoma, and once diagnosed, it must be treated
to prevent blindness.
In most newly diagnosed cases of glaucoma, treatment begins with medication.
For years, there have been three classes of medications: beta blockers (Timoptic being one of the most common); miotic
agents (such as Pilocarpine); and oral agents, which
are carbonic anhydrase inhibitors (like Diamox). Each of these drugs has a range of unpleasant side
Timoptic, which lowers internal eye pressure by
decreasing fluid production in the eye, can have an adverse effect on emphysema
and asthma. Some people on Timoptic find they are
easily fatigued. On the other hand, Pilocarpine,
which increases the fluid outflow of the eye, constricts the pupils, resulting
in poor night vision. Miotic agents like Pilocarpine also
increase the risk of cataracts and retinal detachment, and they irritate
the eye surface. And finally, while many of the oral agents like Diamox do lower internal eye pressure by decreasing fluid
production, they make many people feel generally lousy.
New medications have fewer side effects
Within the past few years, three new drugs have been approved for treating
glaucoma. They are more easily tolerated by patients and have fewer side
The first is a whole new class of medication, which is basically "an
eye-drop form" of the oral agents. Most people know this drug by the name Trusopt. The second medication on the market is an alpha
agonist called Alphagan. This also comes as an eye
drop, and has no known side effects other than eye irritation and chronic
redness. The last of these newer medications is a very powerful agent that both
decreases production of fluid in the eye and increases fluid outflow. This is a
prostaglandin inhibitor called Xalatan. Its side
effects are a bit odd: green-eyed people may find their eye color gradually
changing to brown and their eye lashes growing thicker and longer. Xalatan users also experience general ocular inflammation,
but other unpleasant side effects are absent.
In addition to these new classes of drugs, there are more user-friendly
formulations of the older drugs. For example, Cosopt-a
new combination of Trusopt and Timoptic-needs
to be administered fewer times a day and is less irritating to the eye.
Researchers are also working on a neuroprotectic
agent that is not on the market yet. The goal with this class of medication is
to protect the optic nerve from damage.
When medications fail
When a medical approach to glaucoma treatment fails, laser therapy and
surgery are additional options to consider. Argon laser trabeculoplasty
is a procedure done in the ophthalmologist's office, which increases the fluid
outflow of the eye. It is low-risk, has a high rate of success, and patients
recover from it rapidly. As a matter of fact, trabeculoplasty
is being used more often now as an initial therapy because it can minimize the
use of medications, thereby decreasing unpleasant side effects.
In those advanced cases of glaucoma where laser therapy is not effective, an
outpatient surgical procedure called trabeculectomy
can help to decrease fluid retention in the eye and reduce internal pressure.
Improved sutures and new medications injected after the surgery have enhanced
the success rate of this procedure, which essentially creates a hole in the eye
that acts as a drain. In the most severe cases, a tiny tube with a valve is
inserted to regulate fluid retention and keep the hole open.
With new medications and improved laser and surgical intervention, we are
able to control glaucoma more aggressively now than ever before. Better visual
field testing and optic-nerve imaging also help us track the progression of the
disease. The fact remains, however, that early detection is critical. Since you
can't feel glaucoma or pick up on symptoms until it has progressed, you should
see your eye doctor bi-annually after age 45 for a thorough examination. If you
have a family history of glaucoma, see your eye doctor annually.
Dr. Arleo is board certified in
ophthalmology and serves on the medical staff of Cayuga Medical
Center. He is in practice
with Arleo Eye Associates of Ithaca, and performs surgery at the medical
center and at Surgicare, located on the Convenient Care Campus. He can be
reached at (607) 257-5599, in his office at 100 Uptown Road in Ithaca