Glaucoma types and overview
What is glaucoma?
Glaucoma is an eye condition affecting a person's vision, usually linked to a build-up of pressure inside the eye.
Extra pressure in the eye can damage the optic nerve and nerve fibres from the retina at the back of the eye causing loss of vision.
Glaucoma can be slow to develop and may cause no symptoms until vision starts to get worse.
Glaucoma is estimated to affect over 500,000 people in England and Wales. It causes around 1 in 10 cases of vision impairment.
What causes glaucoma?
Drainage tubes are supposed to stop any pressure building up in the clear fluid in the eye (aqueous humour), but if the tubes get blocked this natural pressure valve doesn't work.
One eye or both eyes may be affected.
Pressure in the eye - called intraocular pressure - should be tested during routine eye tests to check for early signs of glaucoma.
Who has a greater chance of developing glaucoma?
Although it isn't clear why some people get glaucoma and others don't, some things are known to increase the chances of it developing, including:
- Age - glaucoma is more likely as we age
- Ethnic origin - people with African or African-Caribbean backgrounds are at a greater risk
- Being short-sighted ( myopia)
- Having ocular hypertension - increased pressure in the eye
- Having a close family member with glaucoma, such as a parent, brother or sister
- Having medical conditions, including diabetes
- Having a condition causing fibres to block the eye ducts.
Types of glaucoma and symptoms of each
The main types of glaucoma and their symptoms are:
- Chronic open-angle glaucoma. This slow developing type of glaucoma causes a gradual loss of peripheral vision. It is the most common type with few symptoms until peripheral vision starts to become lost.
- Acute-angle closure glaucoma. This type of glaucoma can begin quickly causing throbbing pain and redness in the eye, headaches, blurred vision, halos appearing around lights, pupils becoming dilated, nausea and vomiting. Urgent treatment is needed to prevent permanent vision loss.
- Developmental (congenital) glaucoma in infants. A child is born with this type of glaucoma, which can cause watery eyes, light sensitivity and eyelid spasms. The eyes may also look larger and cloudy and the child may squint or rub their eyes a lot. The child should be seen by a GP or optometrist as soon as possible.
- Secondary and other forms of glaucoma. Symptoms will depend on the underlying condition contributing to the abnormal rise in pressure. These include inflammation inside the eye from uveitis causing halos and light sensitivity. Eye injuries and other eye conditions can also lead to glaucoma.
- Normal-tension glaucoma. In this condition optic nerve damage and vision loss have occurred despite a normal pressure inside the eye.
Seek medical advice if you have symptoms that may indicate glaucoma and have your eyes checked as often as recommended.