Glaucoma is largely an invisible disease
- Glaucoma is the leading cause of irreversible blindness worldwide.
- One in eight Australians over 80 will develop glaucoma.
- First degree relatives of glaucoma patients have an ten-fold increased risk of developing the disease.
- 50% of people with glaucoma in Australia are undiagnosed.
- Australian health care cost of glaucoma in 2005 was $342 million.
- The total annual cost of glaucoma in 2005 was $1.9 billion.
- The total cost is expected to increase to $4.3 billion by 2025.
Source: Tunnel Vision. The economic impact of Open Angle Glaucoma, Centre for Eye Research Australia, 2008
The eye works very much like an old-style camera. In the camera, the light comes in through the shutter, is focused by the lens, falls onto the film and them we take it to be processed.
In the eye, light comes in through the cornea and pupil. It is focused by the lens, falling onto the film in the eye (the retina) and then goes, via the optic nerve (the nerve of sight), to the brain (the processor) for developing.
The shape of the eye is achieved through the circulation of a clear fluid (aqueous). It bathes and nourishes the eye, keeps it firm and gives the eye a certain pressure. High pressure left uncontrolled can lead to damage of the optic nerve and result in vision loss.
It must be noted that eye pressure varies from person to person. What is high pressure for one person may not be for another.
What is glaucoma?
Glaucoma is the name given to a group of eye diseases in
which the optic nerve at the back of the eye is slowly destroyed.
In most people this damage is due to an increased pressure
inside the eye - a result of blockage of the circulation of
aqueous, or its drainage. In other patients the damage may
be caused by poor blood supply to the vital optic nerve fibres,
a weakness in the structure of the nerve, and/or a problem
in the health of the nerve fibres themselves.
Over 300,000 Australians have glaucoma. While it is more
common as people age, it can occur at any age. As our population
becomes older, the proportion of glaucoma patients is increasing.
Video - What is glaucoma?
What are the symptoms of glaucoma?
Chronic (primary open-angle) glaucoma is the most common type.
It has no symptoms until eye sight is lost at a later stage.
Damage progresses very slowly and destroys vision gradually,
starting with the side vision. One eye covers for the other,
and the person remains unaware of any problem until a majority
of nerve fibres have been damaged, and a large part of vision
has been destroyed. This damage is irreversible. It is progressive
and usually relentless. Treatment cannot recover what has
been lost. But it can arrest, or at least, slow down the damage
process. That is why it is so important to detect the problem
as early as possible, to be able to start treatment with as
little damage to the vision as possible.
Photos: Ann Hoste
Who is at risk?
Although anyone can get glaucoma, some people have a higher
risk, those with
- a family history of glaucoma
- short sightedness (myopia)
- long sightedness (hyperopia)
- eye injuries
- blood pressure
- past or present use of cortisone drugs (steroids)
People in these groups should have their first eye check
no later than the age of 35. For most people, it is recommended
to have an eye check for glaucoma by the age of 40. If no glaucoma is found, the NHMRC (2010) Guidelines recommend regular eye health checks for Caucasians over the age of 50 & for those of African & Asian descent regular checks over the age of 40 years, because of the higher prevalence in the latter groups.
What are some of the forms of glaucoma?
Chronic (primary open-angle) glaucoma is the most common
form of this disease. However, other forms occur:
- Low-tension or normal tension glaucoma. Occasionally optic
nerve damage can occur in people with so-called normal eye
pressure. This form of glaucoma is treated in the same manner
as open-angle glaucoma.
- Acute (angle-closure) glaucoma. Acute glaucoma is when
the pressure inside the eye rapidly increases due to the
iris blocking the drain. An attack of acute glaucoma is
often severe. People suffer pain, nausea, blurred vision
and redness of the eye. Immediate medical help should be
sought. If treatment is delayed there can be permanent visual
damage in a very short time. Usually, laser surgery performed
promptly can clear the blockage and protect against visual
- Congenital glaucoma. This is a rare form of glaucoma caused
by an abnormal drainage system. It can exist at birth or
develop later. Parents may note that the child is sensitive
to light, has enlarged and cloudy eyes, and excessive watering.
Surgery is usually needed.
- Secondary glaucomas. These glaucomas can develop as a
result of other disorders of the eye such as injuries, cataracts,
eye inflammation. The use of steroids (cortisone) has a
tendency to raise eye pressure and therefore pressures should
be checked frequently when steroids are used.
History of the word glaucoma
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