Glaucoma can occur for a number of reasons. Many cases are caused by a build-up of pressure in the eye.
The eyeball is filled with a watery substance called aqueous humour, which creates pressure in the eye to give it shape. In healthy eyes, this fluid constantly flows in and out of the eye.
Glaucoma can occur if fluid is unable to drain from the eye properly, resulting in a build-up of fluid and pressure in the eye. This increase in pressure then damages the optic nerve (the nerve connecting the eye to the brain).
It's often unclear why this happens, although there are certain things that can increase the risk of it happening and in a few cases an underlying cause is identified.
Things that can increase your risk of developing glaucoma include:
In a small number of cases, a cause for glaucoma is found.
Possible causes include:
Find out about glaucoma, including what it is, what the symptoms are, why it happens and how it's treated.
Find out about the main types of glaucoma, including open angle glaucoma and angle closure glaucoma.
Find out why glaucoma happens, including what can increase your risk of developing the condition.
Find out where to get tested for glaucoma and what tests may be carried out to diagnose the condition.
Find out about the main treatments for glaucoma, including eye drops, laser treatment and surgery.
Read about Linda Moore, who has had open angular glaucoma since she was 39.She runs the Poole Glaucoma Support Group, which supports people with glaucoma.