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What is
Glaucoma? Glaucoma is a condition caused by increased pressure in the eye which, if left
untreated, can lead to permanently damaged vision and blindness in the
affected eye. The increased pressure in the eye leads to damage in
the optic nerve, which is the nerve responsible for carrying sight images
to the brain. Over time, the patient's vision will begin to deterio
rate because of further damage to the optic nerve.
Glaucoma
can
generally be divided into two main types: ‘open angle’ and ‘
closed angle’. Open angle glaucoma is chronic, generally painless
and progresses slowly; in fact many patients do not notice lost vision
until the disease is significantly advanced. Close angle glaucoma, on
the other hand, is an acute condition which can appear very suddenly and
progress rapidly. Owing to the painful onset of close angle glaucoma, many patients seek medical attention before the damage becomes too
severe.
Once
glaucoma is diagnosed, there
are several treatments which will help to stop any further sight loss.
Sadly, any sight which is lost before treatment begins can never be
regained, as there is currently no complete cure for the damage done by
glaucoma. Early detection and diagnosis can help patients to retai
n as much of their eye sight as possible.
Types
of glaucoma. There are four main types of glaucoma:
-
Chronic
open-angle glaucoma:
this is the most common type of glaucoma and develops very slowly.
-
Primary
angle-closure glaucoma:
this is rare and can occur slowly (chronic) or may develop rapidly (acute)
with a sudden, painful build-up of pressure in the eye.
-
Secondary
glaucoma:
this occurs as a result of an eye injury or another eye condition, such as
uveitis (inflammation of the middle layer of the eye).
-
Developmental
glaucoma (congenital
glaucoma): this is rare but can be serious. It is usually present at birth
or develops shortly after birth. It is caused by an abnormality of the
eye.
How
can it be treated? Glaucoma can be treated with eye drops, l
aser treatment or surgery. However, early diagnosis is important because any damage to the eyes cannot be
reversed. Treatment aims to control the condition and minimize any fu
ture damage. Attending regular optician appointments will help to en
sure that any signs of glaucoma can be detected early and allow treatment
to begin. Without treatment, glaucoma can eventually cause blindness.
Eye
drops for chronic open-angle glaucoma Chr
onic open-angle glaucoma is often treated using eye drops. There
are several different types of eye drops that may be prescribed. The
choice of eye drops may depend on:
-
How
your condition is progressing.
-
Whether
you have any other medical conditions.
-
Whether
you are currently taking any other medications.
-
Whether
the eye drops cause any side effects when you use them
Other
treatments for chronic open-angle glaucoma:
If the use of eye drops does not improve your symptoms, a different type
of treatment may be recommended, such as laser treatment or surgery.
These are described in more detail below.
-
Laser
treatment,which
uses high energy beams of light, can be used to open up the blocked
trabecular meshwork (drainage tubes) within your eye. This is called laser
trabeculoplasty. Anaesthetic (painkilling) eye drops will be put into your
eye and a special lens will be placed in front of your eye. The laser will
be shone through the lens and will make small holes in the trabecular
meshwork. This allows more fluid to drain out of your eye and reduces the
intraocular pressure. An alternative to laser trabeculoplasty is
cyclodiode laser treatment. This involves destroying some of the tissue in
the eye that produces aqueous humour. It creates less fluid in the eye,
which reduces the intraocular pressure. Laser treatments are usually quick
and painless, although during the procedure you may feel a brief twinge of
discomfort or heat. You may still need to use eye drops (see above) a
fter having laser treatment.
-
Surgery:
A
trabeculectomy is the most common type of glaucoma surgery. It involves
removing part of the trabecular meshwork to allow fluid to flow through
the eye's drainage system. The procedure will be carried out under local
anaesthetic (you will still be conscious). If you are having surgery, your
surgeon may choose to use anti-scarring medicines. These can improve the
success of the operation by preventing scar tissue forming as your eye
heals. You may be prescribed mitomycin C or 5-fluorouracil. These
medications are unlicensed for the treatment of glaucoma. This means that
the manufacturers of these medications have not applied for a license for
their medication to be used to treat glaucoma. In other words, the
medications have not undergone clinical trials (research that tests one
treatment against another) to see if they are effective and safe in
treating glaucoma. Many experts will use an unlicensed medication if they
think the medication is likely to be effective and the benefits of
treatment outweigh any associated risk. The National Institute for Health
and Clinical Excellence (NICE) has issued guidance for the treatment of
chronic open-angle glaucoma. It suggests that these medicines can be used.
If your ophthalmologist is considering prescribing an unlicensed
medication, they should inform you that it is unlicensed, and discuss the
possible risks and benefits with you
Acute
angle-closure glaucoma:
As acute glaucoma develops rapidly, the condition needs to be treated
quickly. The most common forms of treatment for this type of
glaucoma include:
-
Eye
drops – see
above for further details.
-
Systemic
medicines – these are injected into your bloodstream to quickly reduce the pressure in
your eye.
-
Laser
treatment (called
laser iridotomy) – this uses high-energy beams of light to create holes in your iris (coloured part of the eye) to open the angle and enable
fluid to flow; both eyes may need to be treated, even if only one has
acute angle-closure glaucoma, because this form of glaucoma may develop in
both eyes at some point.
-
Surgery
–
a trabeculectomy (surgery to remove part of the drainage tubes) is the
most common form of surgery for acute glaucoma.
-
If
you also have a cataract, which
is a cloudy patch in the front of your eye, removing it may open the angle
in your eye and control the intraocular pressure.
-
Miotics -
Acute angle-closure glaucoma may also be treated with a medication called
a miotic, such as pilocarpine. Miotics work by opening up the blocked
trabecular meshwork, which should improve the drainage of aqueous humour
out of your eye. You may need to use these eye drops up to four times a
day. Miotics should be used with caution in people who have certain
medical conditions, including: heart disease, high blood pressure,
asthma. Miotics can also cause some side
effects, such as a headache, which may be severe during the first two to
four weeks of treatment, burning or itchy eyes, blurred vision, which may
affect your ability to drive
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