Glaucoma is the name given to a group of eye conditions in which the optic nerve is damaged where it leaves the eye. Although any vision which has been lost to glaucoma cannot be recovered, with early diagnosis, careful monitoring and regular use of the treatments, further damage to vision can be prevented and most patients retain useful sight for life. While there are usually no warning signs, regular eye tests will help detect the onset of the disease
Glaucoma is one of the world's leading causes of blindness. In the UK, about two per cent of the population over 40 have the condition.
Glaucoma does not usually cause any symptoms to begin with.
It tends to develop slowly over many years and affects the edges of your vision (peripheral vision) first.
For this reason, many people do not realise they have glaucoma, and it's often only picked up during a routine eye test.
If you do notice any symptoms, they might include blurred vision, or seeing rainbow-coloured circles around bright lights.
Both eyes are usually affected, although it may be worse in one eye.
Very occasionally, glaucoma can develop suddenly and cause:
There are four main types of glaucoma: primary open angle glaucoma, primary angle closure glaucoma, secondary glaucoma, developmental glaucoma (congenital glaucoma).
Primary open angle glaucoma - This is the most common type of glaucoma and develops very slowly
Angle closure glaucoma - This is rare and can occur slowly (chronic) or may develop rapidly (acute) with a sudden, painful build-up of pressure in the eye
Secondary glaucoma -This occurs as a result of an eye injury or another eye condition, such as uveitis (inflammation of the middle layer of the eye)
Developmental glaucoma (congenital glaucoma) -This is rare but can be serious. It is usually present at birth or develops shortly after birth. It is caused by an abnormality of the eye.
In England, about 480,000 people have chronic open-angle glaucoma. Among white Europeans, about 1 in 50 people over 40 years of age and 1 in 10 people over 75 years of age have chronic open-angle glaucoma.
You are also at increased risk of developing open-angle glaucoma if you are of black-African or black-Caribbean origin.
The other types of glaucoma, such as acute angle-closure glaucoma, are much less common. However, people of Asian origin are more at risk of getting this type of glaucoma compared with those from other ethnic groups.
Glaucoma can occur for a number of reasons.
Most cases are caused by a build-up of pressure in the eye when fluid is unable to drain properly.
This increase in pressure then damages the nerve that connects the eye to the brain (optic nerve).
It's often unclear why this happens, although certain things can increase the risk, including:
It's not clear whether you can do anything to prevent glaucoma, but having regular eye tests should pick it up as early as possible.
You can self-fund or use private medical insurance to fund your treatment.