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GLAUCOMA TREATMENTS - a patient's guide
Natalie Gauld - Pharmacy Educator
Introduction
Glaucoma is a major cause of loss of vision. Open-angle
glaucoma slowly happens over time, and by the time symptoms
occur it is very late and some loss of eyesight will happen.
This article will discuss the treatments for simple or open-angle
glaucoma, and not for the sudden painful glaucoma, angle-closure
or closed-angle glaucoma.
In many patients with simple glaucoma there is an increase
in pressure in the eye that is higher than the pressure
your eye can cope with, and this causes cupping of the optic
disk and damage to the optic nerve, and long-term loss of
vision.
Some people's eyes can cope better with high pressure
than others so your optometrist will not only measure the
pressure, but will also look for cupping of the optic disk
and may check your visual field (how far around your vision
goes when you are looking straight ahead).
The increased pressure is from fluid building up in a
confined space, perhaps because the drainage system is not
working very well. The pressure needs to be lowered to reduce
the long-term loss of sight, and eye drops are the first
choice for doing this.
If the first type of eye drops don't work then another
type is usually trialed. Sometimes you may need two different
types of eye drops at once. If this still doesn't reduce
the pressure sufficiently, tablets may be used, or laser
treatment or surgery may be required.
Eye drops or tablets will help to prevent loss of eyesight.
To do this they must be used every day without missing any
doses and are usually used for a lifetime, unless you undergo
surgery or laser treatment.
Medicines and brands:
There are many different eye drops for glaucoma and they
belong to different "groups" which are based on the way
they work. The medicines are discussed by group below.
The eye drops reduce pressure either by increasing the
drainage for the fluid in the eye, or reducing the amount
of fluid produced. Because there are different groups, if
one doesn't work or if it has side effects, there will be
another one to try that may be a better choice for you.
All eye drops can be absorbed into the blood stream, and
so they can cause side effects in other parts of the body,
not just the eye. The eye drops usually contain a preservative
that may be incompatible with contact lenses - if you use
contact lenses check with your eye specialist if your eye
drops will be compatible with your lenses.
Beta blocker eye drops
Betaxolol (Betoptic)
Carteolol (Teoptic)
Levobunolol (Betagan)
Metipranolol
Timolol (Timoptol)
The beta-blockers are usually the first type of eye drops
to start on because they are generally effective and well
tolerated (meaning side effects are not a problem for most
people).
These medicines must not be used in people with an extra-slow
heart beat, heart block, uncontrolled heart failure and
some other heart problems. They should not be used in people
with asthma or emphysema because they cause tightening of
the breathing passages. Special care may be needed in people
with very severe allergies as the beta-blockers may increase
the sensitivity in these people and affect their response
to adrenaline. Special care is needed with the elderly and
diabetics.
The most common side effect is probably eye discomfort
for a short time. Other eye effects such as itching sensation,
blurred vision, tear production or dryness of eyes are less
common.
Side effects for other parts of the body are uncommon
but can include slowing of the heartbeat, tightening of
the airways, headache, and dizziness. Let your doctor know
if you have any effects especially on the heart or breathing.
There are possible interactions with beta-blocker tablets
(a heart medicine), reserpine, and some psychiatric medicines.
Miotics
Pilocarpine (PV Carpine, Pilocarpine, Pilopt, Sno Pilo)
Pilocarpine eye inserts replace once a week (Ocusert)
Carbachol (Isopto Carbachol)
Physostigmine
These eye drops have the difficulty of causing blurred
vision and making the pupil small which reduces the amount
of light going into the eye and reduces the field of vision.
Pilocarpine has to be used frequently (e.g. four times a
day) but also comes in an insert form called Ocusert that
is placed under the eyelid and left there for seven days.
Ocusert has continuous release of pilocarpine so is more
convenient.
Carbachol is not used very often but can be helpful in
people allergic to pilocarpine.
Alpha agonists
Apraclonidine (Iopidine)
Brimonidine (Alphagan)
These eye drops may be used if others have not worked
well enough. Bimonidine is the more popular of the two.
These eye drops must not be used in patients who are allergic
to any ingredient in the drops or to clonidine. Care needs
to be taken in patients with severe heart disease, depression,
Raynaud's disease, low blood pressure, thromboangiitis obliterans,
depression, and poor blood flow to the head or heart.
These eye drops can react with other medicines so always
check with your doctor or pharmacist if you are taking any
other medicines.
Side effects include dizziness and sleepiness (do not
drive if affected), and dry mouth. Red eyes, itching, swelling
of the eyelids, and tear production show allergy. If these
symptoms occur talk to your doctor or pharmacist.
Carbonic anhydrase inhibitors
Acetazolamide tablets (Diamox)
Dorzolamide eye drops (Trusopt)
Usually the tablets are a last resort due to their side
effects, which include tiredness, depression, reduced appetite,
altered taste and stomach upset including diarrhoea.
The eye drops are less problematic with the most common
side effects being bitter taste (which doesn't last long)
and burning or stinging of the eyes. Therefore, the eye
drops are treated differently to the tablets and can be
tried early in the treatment of glaucoma.
Others
Latanoprost (Xalatan) - a prostaglandin-type eye drop
Dipivefrine (Propine, Dipoquin) - adrenaline type
Adrenaline (Eppy, Simplene)
Pilocarpine + timolol (Timpilo)
Latanoprost is a new product for glaucoma used mainly
if the other eye drops are not working well enough, or if
other eye drops have problem side effects for a person.
It is used once daily, at night. Possible side effects include
a change in eye colour, growing of eyelashes and darkening
of the skin around the eyes.
Adrenaline is not often used but dipivefrine is quite
common as it has fewer side effects than adrenaline. Dipivefrine
can cause red eyes.
Patient information:
Follow the instructions on the label of the medicine or
as directed by your doctor.
The medicine must be used every day to keep the pressure
in the eye down continuously. Do not miss any doses.
Throw your eye drops away one month after first opening.
It may be useful to record the date of opening or the date
to be thrown away on the bottle or on a calendar. If eye
drops are used after this month there is a risk of contamination
with bacteria which can then cause an eye infection.
There is a family link with glaucoma, so if you have been
diagnosed with glaucoma, your close relatives should also
be checked for glaucoma.
For many of these eye drops it is wise to shake the bottle
before each use (check the box).
Sometimes it is recommended to apply gentle pressure to
the skin on top of the tear duct straight after using eye
drops to help reduce the amount going into the blood stream.
Let your doctor know if you are having any problems with
your eye drops as another eye drop may suit you better.
Keep your eye drops away from direct sunlight and away
from heat.
If you have other eye problems (e.g. infection or injury)
check with your doctor about whether to start on a new bottle
of your glaucoma eye drops. This is because you may be more
likely to have problems with contamination of the eye drops
in this case.
Always wash your hands well before using the eye drops.
Avoid touching the tip of the eye drop bottle to the eye
or with your hand. Replace the cap promptly on the bottle.
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