Medications
Medications to lower the pressure inside the eye (intraocular pressure, or IOP) are used to treat all
types of
glaucoma. They work either by reducing the amount of
fluid (aqueous humour) that is produced by the eye or by
increasing the amount of fluid that drains out of the eye. These medications
may be given as eyedrops; as pills; in liquid form by mouth; or, in emergency
situations, through a vein. In most cases, eyedrops are used first.
In a sudden (acute) attack of
closed-angle glaucoma, medications may be used to
lower the pressure in the eye. Medications that close (constrict) the pupil may
be used to open the
drainage angle. If medications lower the eye pressure
after an episode of acute closed-angle glaucoma, laser treatment is usually
done soon afterwards to prevent such an episode from occurring again. If the
medications do not lower the pressure in the eye, laser treatment will need to
be done immediately.
In
congenital glaucoma, medications may be used to reduce
the pressure in the eyes and decrease the cloudiness of the clear front surface
(cornea) of the eye. Medications usually do not work over a long period of time
and are usually used only until surgery can be done.
In the media, much has been said about the possibility of using
marijuana to treat glaucoma. Inhaled marijuana smoke
has been shown to result in an average 25% reduction in
intraocular pressure (IOP), but the effect lasts only
for about 3 to 4 hours. Also, not all people who use marijuana have this
reduction in IOP; it only occurs in about 60% to 65% of users. The smoke also
has toxic effects on other parts of the body, particularly the lungs, and
substances in the smoke cause changes in mental state. The amount of marijuana
a person needs to smoke to keep eye pressure down would cause significant side
effects. Because of these toxic and psychoactive effects, along with the short
duration of the beneficial effect of lowering pressure in the eye, marijuana is
considered a poor treatment option and is not recommended for glaucoma.9, 10
Medication Choices
Medications used to treat glaucoma lower the pressure in the eyes
(intraocular pressure, or IOP) by either decreasing the amount of fluid
produced by the eyes or increasing the amount of fluid that drains out of the
eyes.
Medications that decrease the amount of fluid produced by the eye
include:
Medications that increase the amount of fluid that drains out of
the eye include:
What To Think About
When medications are used to treat glaucoma, the goal is to
prevent further damage to the optic nerve by lowering the pressure in the eyes.
The level of pressure in the eye needed to damage the optic nerve varies from
one person to another. For this reason, a single
target eye pressure cannot be used for everyone. Your
target pressure may need to be adjusted if the optic nerve shows further damage
despite treatment.
When glaucoma has already caused vision loss, further vision loss
may develop even after the pressure in the eye is lowered to the normal range
with medication.
In most cases, medications used to treat glaucoma must be
continued daily for the rest of your life. Putting eyedrops in the eye at
specific times of the day may be inconvenient. Eyedrops may also cause
discomfort. You need to follow the prescribed daily schedule for your eyedrops
in order for them to work properly.
- Discuss the goals of treatment, how long the
medication will be tried, and the possible side effects with your health
professional. Eye medications can cause symptoms throughout the body. Report
side effects to your eye doctor.
- Knowing how to correctly insert
your eyedrops can make the medication work better and may help you avoid side
effects. A medication card stating which medications need to be taken at
different times of the day can be helpful in reminding you to take medications.
Use multicoloured bottle caps to help you tell different medications
apart.
- You will need follow-up visits with your health professional
shortly after starting a new medication to determine whether it is working as
well as it should be and to discuss any side effects or medication schedule
problems.
Medications for glaucoma can be expensive. Some
cost-saving tips such as using a measured-dose
dispenser may help.
Let all your health professionals know that you are taking
glaucoma medications. Other medications that you are taking may need to be
adjusted or stopped to prevent side effects.
While there are fewer complications from the new surgical
procedures for glaucoma, medication treatment still usually has fewer side
effects than surgery. Many people who use glaucoma medications may never need
surgery for glaucoma.