Glaucoma is a common eye condition that affects people of all ages but is most common in adults in their 70s and 80s. It’s a condition in which the optic nerve, that connects the eye to the brain, becomes damaged. It’s generally caused by a build-up of fluid in the eye, which increases pressure inside the eye

Types of glaucoma

There are several types of glaucoma, including:

• Primary open angle glaucoma (the most common form of the condition – it's triggered when the drainage channels in the eye become clogged and usually develops slowly over some years)

• Secondary glaucoma (triggered by an operation, medicine, injury or an underlying eye condition like inflammation of the eye)

• Childhood glaucoma (also referred to as congenital glaucoma – childhood glaucoma is uncommon, occurs in very young children and is caused by an abnormality of the eye)

• Acute angle closure glaucoma (an uncommon type of glaucoma caused by drainage channels in the eye becoming suddenly blocked. It can be painful and may cause permanent damage if not treated quickly)

What causes or increases the risk of developing glaucoma?

Glaucoma can develop or become more likely to occur for several reasons, including:

• Ethnicity – those with African, Caribbean or Asian heritage are more at risk

• Age – you are more likely to develop glaucoma as you become older

• Family medical history – if you have a parent or sibling with glaucoma, you will have a higher chance of developing it

• Other medical conditions, such as diabetes

It’s not certain whether anything can be done to prevent glaucoma. But do keep in mind that going for regular eye tests will catch the condition in its early stages. You should go for a routine eye test at least every two years, even if you're not experiencing any problems with your eyes or vision.

What are the symptoms of glaucoma?

Primary open angle glaucoma rarely causes obvious symptoms. It usually develops over many years and affects your peripheral vision. Therefore, many people don’t realise they have it until it’s found during a routine eye test. In the case of acute angle closure glaucoma, symptoms can come on quickly and may include:

• Intense pain or redness in your eyes

• Nausea and vomiting

• Headaches

• Blurry vision or seeing rings around lights

Visit an optometrist or GP if you’re concerned about your eyes or your vision. Early diagnosis and treatment can prevent glaucoma from getting worse. If left without treatment, glaucoma can eventually lead to blindness. If you suddenly develop symptoms of glaucoma, you should visit your nearest eye casualty unit or accident and emergency department as soon as possible. Sudden symptoms may signal an emergency that should be treated immediately.

How do you test for glaucoma?

Your optometrist will perform a series of quick and painless tests to check for glaucoma, including vision tests and measurements of the pressure inside your eye.

If you are diagnosed with glaucoma, you should see a specialist eye doctor (ophthalmologist) to discuss treatment. An ophthalmologist can let you know how far the condition has developed and what may have caused it, as well as assessing any damage done to your eyes by glaucoma.

Specific tests to diagnose and monitor glaucoma include:

• Eye pressure test (where an instrument called a tonometer is used to measure the pressure inside your eye)

• Gonioscopy (an examination of the front part of your eye, or the fluid-filled space between the iris and cornea, where fluid should drain out of your eye)

• Visual field test (a visual field test checks for missing areas of vision with a sequence of light spots)

• Optic nerve assessment (eye drops will be used to enlarge pupils, then eyes are examined using either a slit lamp or an eye scan called optical coherence tomography)

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Glaucoma can be treated but early detection is important. If left untreated, glaucoma can cause visual impairment and damage that cannot be reversed. But if it’s detected and treated early enough, further damage to vision can be minimised or prevented.

How is glaucoma treated? 

It’s not possible to reverse any loss of vision that has occurred before glaucoma was diagnosed, but treatment can help stop your vision loss from worsening. Treatment will depend on which type of glaucoma you have, but options include:

• Eye drops – these can help to lower pressure in your eyes (they’re normally used between one and four times a day, and it’s important to use them as directed, even if you haven’t noticed any problems with your vision)

• Laser treatment – this can remove blockages in drainage tubes or reduce the amount of fluid produced in your eyes (a high-energy beam of light is carefully aimed at part of your eye to stop fluid from building inside it)

• Surgery – this can help the fluid to drain more easily (the most common type of surgery for glaucoma is called trabeculectomy, which improves the drainage of fluid within the eye)

Primary open angle glaucoma is generally treated with eye drops. If drops don’t help, laser treatment or surgery may be offered. Treatment for other types of glaucoma include:

• Secondary glaucoma – eye drops, laser treatment or surgery depending on the underlying cause

• Acute angle closure glaucoma – immediate treatment in hospital along with medication to reduce pressure in the eye, followed by a laser treatment

• Childhood glaucoma – surgery to remedy the underlying problem in the eye that resulted in the build-up of fluid and pressure

Next steps

• If you’re experiencing symptoms such as nausea and vomiting, blurred vision, tenderness around the eyes or seeing rings around lights, visit your nearest eye casualty unit or accident and emergency department

• If you have glaucoma, review your treatment options with your GP or ophthalmologist. These are likely to include eye drops, laser treatment and surgery

• It’s important to go for routine eye tests every two years whether you have symptoms or not