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What treatment methods are available for glaucoma?
Two
of the most common treatments for glaucoma are medicines and laser treatment.
Laser treatment is required in most cases of narrow-angle glaucoma, and is used
as an alternative or supplement to treatment of open-angle glaucoma. The goal in
treating glaucoma is to preserve the patient's vision, to reduce intraocular
(inside the eye) pressure, and to protect the optic nerve. The only proven method
of treatment for glaucoma is by reducing the pressure inside the eye.
Medical therapy
There are several classes of medicines used to treat glaucoma, with many
advances having been made over the past several years. Each medicine has a
different way of reducing pressure, either working to reduce the
production of aqueous humor (fluid in the front part of the eye) or to reduce resistance to the outflow of aqueous. These medicines can be used
individually or together.
- Beta blockers — Beta blockers work by reducing aqueous production. They
have a long, proven track record of effectiveness. Some of the side effects of
beta blockers include asthma, low blood pressure, slowed heart rate, and elevated
cholesterol.
- Alpha-2 agonists — These medicines also work by reducing aqueous
production. They are slightly less effective than beta blockers. Their side
effects can include an allergic reaction, redness or irritation in the eyes, and
—
in rare instances — a decrease in mental alertness.
- Carbonic anhydrase inhibitors — Another medicine that works by
reducing aqueous production, carbonic anhydrase inhibitors can cause serious
side effects as an oral medicine. These can include fatigue, loss of appetite,
numbness and/or tingling in the hands and feet, and stomach upset. When used as
a topical medicine it is less effective, however there are very few side
effects except occasional allergic reactions.
- Prostaglandins — Prostaglandins work by decreasing the resistance to
aqueous outflow and have been shown to be very effective in reducing intraocular
pressure. Side effects include redness, irritation or inflammation in the eye,
darkening of the iris, and an increased growth of eyelashes.
There are a number of laser surgeries used to treat glaucoma. The most common
procedures are:
- Laser trabeculoplasty — During this procedure, the trabecular meshwork
(drainage canals surrounding the iris) is mildly heated, causing a thermal burn.
This allows for an increase in the aqueous outflow in the area surrounding the
laser burn, thus relieving pressure inside the eye. Pressure is reduced in 60
percent to70
percent of the patients in whom a laser trabeculoplasty is performed. However,
about half of those patients require further treatment within two to five years.
A maximum of two re-treatments can be performed. Laser trabeculoplasty can be
considered as an alternative to medicine as therapy for newly diagnosed
glaucoma.
- Selective laser trabeculoplasty — This procedure is similar to a standard
trabeculoplasty. It involves using a laser with a different wavelength,
selectively treating the trabecular meshwork without the use of a thermal burn.
This leaves the trabecular meshwork intact, and can therefore be repeated
multiple times, if necessary.
- Laser peripheral iridotomy — Required in cases of narrow angle
glaucoma, this procedure creates a tiny opening in the iris. This small opening
reduces the fluid pressure behind the iris, and allows it to fall backward, away
from the drainage channels of the eye. If complete opening of the channels
occurs, the intraocular pressure might return to normal without the need for any
additional glaucoma medicine.
Today, there are many options for treating glaucoma with laser therapy and
medicines. Over the past several years, the number of options has increased, so that doctors now have many more tools available to them to help prevent
vision loss that can result from this glaucoma.
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