Glaucoma results from a build up of pressure inside the eye that is caused when the fluid that nourishes the iris (aqueous humour) cannot drain away. This pressure can damage the optic nerve and cause vision to narrow or blank areas to appear. Glaucoma can happen at any age, however, it is usually related to ageing.
Pressure build-up causes glaucoma
The eye is made up of two chambers, the anterior and posterior, separated by the lens. The anterior (front) chamber contains the visible eye components, such as the coloured part (the iris), and is plumped up and nourished by aqueous humour.
The aqueous humour is regularly drained to keep a constant, normal pressure inside the anterior chamber. Sometimes, this fluid can't drain away, leading to a build-up of pressure inside the eye. This is called glaucoma.
Pressure can damage the optic nerve
If the special channels that drain the aqueous humour become blocked and prevent the fluid from draining properly, the pressure within the eye (called intra-ocular pressure) rises. This extra pressure can damage the optic nerve, which connects the eye to the brain. The damage can cause two different vision problems:
- The edge of the field of vision can fade, causing vision to narrow.
- Blank areas can develop closer to the centre of vision.
Onset can be slow or sudden
Glaucoma can present itself in two different ways:
- Chronic or open-angle glaucoma - develops slowly over time. A person with chronic glaucoma might not even realise they have a problem until their eyesight becomes affected.
- Closed-angle glaucoma - vision loss is sudden and painful.
A condition linked to ageing
Glaucoma can happen to anyone, but the risk factors include:
- Being older than 40 years.
- A family history of glaucoma.
- Short sightedness.
- Diabetes.
Glaucoma is not directly related to blood pressure.
Vision loss may be permanent
Early detection of glaucoma is vital. Screening tests are available and are important for anyone at risk. Glaucoma can be managed by regular treatment from an eye specialist, but any vision lost before the start of treatment is usually permanent. Treatment options include eye drops, medication and, sometimes, surgery as a last resort.
Where to get help
- Your doctor.
- Eye specialist.
- Vision Australia’s Vision Information Line Tel.1800 331 000, for help to maintain your independence.
Things to remember
- Glaucoma is an eye condition caused by a build-up of pressure inside the eyeball.
- Onset can be sudden or slow.
- Any vision lost before the start of treatment is usually permanent.
You might also be interested in:
Eye care - orthoptists.
Eye conditions - iritis.
Eye disorders - some common problems.
Eyes explained.
Glaucoma - detection and management.
Headache and eye problems.
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