Glaucoma
Published by Bupa's health information team, November 2009.
This factsheet is for people who have glaucoma, or who would like information about it.
Glaucoma is the name for a group of eye conditions where the optic nerve becomes damaged and vision deteriorates. The damage to the optic nerve can be caused by an increase in pressure within the eye or a weakness in the optic nerve, or both.
- About glaucoma
- Types of glaucoma
- Symptoms of glaucoma
- Causes of glaucoma
- Diagnosis of glaucoma
- Treatment of glaucoma
- Prevention of glaucoma
- Questions and answers
- Related topics
- Further information
- Sources
About glaucoma
If you have glaucoma, your optic nerve is damaged at the point where it leaves your eye.
Sometimes the damage can result from an increase in pressure in your eye. This increase in pressure usually happens when fluid (the aqueous humour) in the front part of your eye (the anterior chamber) doesn't drain away properly. Usually the amount of fluid produced is balanced by the amount draining away, so the pressure in the front part of your eye stays constant. If you have glaucoma, the pressure within your eye can be so high that your optic nerve is damaged and you may begin to lose your sight.
Glaucoma can also result from a weakness in your optic nerve, which can lead to damage even when the pressure in your eye appears to be normal.
In most people who have glaucoma, the condition is caused by both high pressure and a weakness in the optic nerve but to varying extents.
Getting treated early can prevent you from losing your sight.
TThe different parts of the eye
Types of glaucoma
Chronic glaucoma
This includes primary open angle glaucoma, the most common type.
Chronic glaucoma develops very slowly so that any damage to the nerve and eyesight happens gradually.
If the drainage channels through which the fluid flows become blocked, it can lead to chronic glaucoma. This can cause the pressure within your eye to rise very slowly.
A form of chronic glaucoma called normal tension glaucoma can occur even if the pressure in your eye is within the normal range. It's thought that a poor blood supply or a weakness in the optic nerve makes the nerve more likely to get damaged.
Acute glaucoma
This is also called closed angle glaucoma. It happens when the pressure in your eye rises very quickly. The drainage angle that lies between the cornea (the clear window at the front of your eye) and the iris (the part that gives your eye its colour) narrows suddenly. This prevents the fluid from flowing out of your eye.
Acute glaucoma can be very painful and you need to seek urgent medical attention. It can cause permanent sight damage unless treated quickly. This type is much less common than chronic glaucoma.
Secondary glaucoma
This occurs as a result of other eye conditions, such as if you injure your eye or you get repeated inflammation in it. If you have diabetes, you may be at risk of developing a type of secondary glaucoma called rubeotic glaucoma.
Congenital glaucoma
This is a very rare condition where a baby is born with glaucoma.
The condition occurs while the baby's sight is still developing. The tissues at the angle of the anterior chamber don't develop properly and this blocks the flow of the fluid out of the eye.
Symptoms of glaucoma
If you have chronic or secondary glaucoma, you probably won't notice any symptoms until your sight has deteriorated considerably. This is because the first part of your sight to be affected is the outer or peripheral field of vision. Central vision, used to focus on an object (for example when you're reading), isn't usually affected until much later on in the disease.
Acute glaucoma tends to come on very quickly. Symptoms include:
- loss of sight
- pain
- blurred vision or a halo around lights
- feeling sick or vomiting
- the white of your eye may look red
If you think you're having an attack of acute glaucoma, you need to go to hospital immediately.
It can be difficult to recognise symptoms of congenital glaucoma but if your baby has watering eyes, is very sensitive to light or has cloudy, white, enlarged eyes, make an appointment to see your GP.
Causes of glaucoma
Glaucoma is caused by an increase in pressure within your eye or a weakness in the optic nerve, or both. You're more likely to get glaucoma later in life. Not many people under 40 will develop the condition, but two in 100 people over the age of 40 and five in 100 people over the age of 70 will develop some type of glaucoma.
Other factors that can increase your chances of getting glaucoma include:
- ethnicity - if you're of African or black Caribbean origin, you're more at risk and it may affect you earlier in life and be more severe
- family history - if you have a close relative with glaucoma, it's important to have regular eye tests from the age of 35
- being very short-sighted
- diabetes
Diagnosis of glaucoma
You may not get symptoms until you have significant loss of sight. Therefore, screening tests are important to detect glaucoma. An optometrist - a registered health professional who examines eyes, tests sight and dispenses glasses and contact lenses - can do these during a routine sight test.
As glaucoma is more common if you're over 40 it's important to have an eye test at least every two years from this age onwards. It's also important to be tested regularly if you're at risk of developing glaucoma, such as if a family member has it or you have diabetes.
An eye test usually takes about 30 minutes. If you wear glasses, take them with you and any medicines you're taking.
There are a number of tests for glaucoma. Your optometrist may:
- look at your optic nerve by shining a light from a special torch into your eye
- look at the thickness of your cornea
- measure the pressure in your eye using a tonometry test
- measure your field of vision in a perimetry test by showing you a sequence of spots of light on a screen and asking you which ones you can see
If your optometrist thinks you may have glaucoma, you will be referred to an ophthalmologist (a doctor who specialises in eye health, including eye surgery) for more tests. These may include a gonioscopy test to look at the area in your eye where the fluid drains out.
Treatment of glaucoma
Treatment for glaucoma aims to lower the pressure inside your eye to reduce the risk of future sight loss if it hasn't already deteriorated, or prevent any further loss of sight. Treatment can't reverse any existing optic nerve damage, so it won't improve your sight if it has already deteriorated.
Options include medicines given as eye drops, laser treatment and surgery.
Medicines
There are different types of eye drops available for treating glaucoma. These include:
- prostaglandin analogues that help your eye's internal fluid drain out more quickly
- beta-blockers that reduce the pressure in your eye - they slow down the build-up of fluid by reducing production of it
Several other types of medicine are available in drop and tablet form, as alternatives or in addition to beta-blockers or prostaglandins. It's important that you use any prescribed eye drops every day as advised by your doctor to ensure consistent lowered pressure in the eye. If you don't, the pressure in your eye will rise again.
There are different side-effects for each type of medicine. Ask your doctor or pharmacist for more information. If you think your medicine is causing a side-effect, speak to your doctor as soon as possible. He or she can advise you and if necessary can prescribe a different drop or consider other treatments.
Surgery
Laser treatment
A laser can be used to open the holes in the draining system to help fluid drain out of your eye or stop your eye producing as much fluid.
The procedure is usually quick and causes little discomfort. It can be done under local anaesthesia and you will be able to go home the same day. The success of this type of treatment varies from person to person, and you may need to continue using eye drops after laser treatment.
Trabeculectomy surgery
You may be able to have surgery if medicines and/or laser treatment haven't lowered the pressure in your eye.
There are a range of operations and the most commonly performed is trabeculectomy. In this operation a tiny opening is created in your eye wall to allow fluid to escape under the thin lining of the white of your eye (the conjunctiva) and be absorbed back into your bloodstream. You may have the operation under local or general anaesthesia.
Prevention of glaucoma
If you're over 40, it's important to have regular eye tests to check for the early signs of glaucoma. If you have a family history of glaucoma, it's important to be tested regularly from the age of 35.
Related topics
Further information
International Glaucoma Association
01233 648170
www.glaucoma-association.com
Royal National Institute of Blind People
0303 123 9999
www.rnib.org.uk
Sources
- Understanding glaucoma. Royal National Institute of Blind People. www.rnib.org.uk, accessed 4 June 2009
- Glaucoma: diagnosis and management of chronic open angle glaucoma and ocular hypertension. National Institute for Health and Clinical Excellence (NICE), April 2009. www.nice.org.uk
- Glaucoma. BMJ Clinical Evidence. www.clinicalevidence.com, accessed 4 June 2009
- Acute angle closure glaucoma. International Glaucoma Association. www.glaucoma-association.com, accessed 4 June 2009
- Secondary glaucoma. GP Notebook. www.gpnotebook.co.uk, accessed 4 June 2009
- Congenital glaucoma. International Glaucoma Association. www.glaucoma-association.com, accessed 4 June 2009
- Understanding glaucoma. The Royal College of Ophthalmologists. www.rcophth.ac.uk, accessed 4 June 2009
- Acute (closed angle) glaucoma. GP Notebook. www.gpnotebook.co.uk, accessed 4 June 2009
- About glaucoma. International Glaucoma Association. www.glaucoma-association.com, accessed 4 June 2009
- Congenital glaucoma. GP Notebook. www.gpnotebook.co.uk, accessed 4 June 2009
- Eye care. Directgov. www.direct.gov.uk, accessed 4 June 2009
- Rolim de Moura CR, Paranhos Jr A, Wormald R. Laser trabeculoplasty for open angle glaucoma. Cochrane Database of Systematic Reviews 2007, Issue 4. DOI: 10.1002/14651858 doi:10.1002/14651858
This information was published by Bupa's health information team and is based on reputable sources of medical evidence. It has been peer reviewed by Bupa doctors. The content is intended for general information only and does not replace the need for personal advice from a qualified health professional.
Publication date: November 2009
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