Glaucoma is an eye condition where the optic nerve, which connects your eye to your brain, becomes damaged. It can lead to loss of vision if not detected and treated early on.

It usually occurs when the fluid in the eye cannot drain properly, which increases the pressure inside the eye and puts pressure on the optic nerve.

Glaucoma is a common condition, but many people won't realise they have it because it doesn't always cause symptoms in the early stages.

It can affect people of all ages, including babies and young children, but is most common in adults in their 70s and 80s.

This page covers

Symptoms of glaucoma

Glaucoma doesn't usually have any symptoms to begin with and is often only picked up during a routine eye test.

Many people don't realise they have it because it develops slowly over many years and tends to cause a loss of peripheral vision (the edge of your vision) at first.

Both eyes are usually affected, although it may be worse in one eye. Without treatment, it can eventually lead to blindness.

Very occasionally, glaucoma can develop suddenly and cause:

  • intense eye pain
  • a red eye
  • headache
  • tenderness around the eyes
  • seeing rings around lights
  • blurred vision

When to get medical advice

Visit an opticians or your GP if you have any concerns about your vision.

If you have glaucoma, early diagnosis and treatment can help stop your vision getting worse.

If you develop symptoms of glaucoma suddenly (see above), go to your nearest accident and emergency (A&E) department as soon as possible.

This is a medical emergency that may require immediate treatment.

Types of glaucoma

There are several different types of glaucoma.

Some of the main types are:

  • primary open angle glaucoma – the most common type, which tends to develop slowly over many years
  • primary angle closure glaucoma – an uncommon type that can develop slowly or quickly
  • secondary glaucoma – glaucoma caused by an underlying eye condition, such as uveitis (inflammation of the eye)
  • normal tension glaucoma – where the pressure inside the eye is at a normal level
  • childhood glaucoma (congenital glaucoma) – a rare type that occurs in very young children, caused by an abnormality of the eye

Read more about the types of glaucoma.

Causes of glaucoma

Glaucoma is usually caused by a blockage in the part of the eye that allows fluid to drain from it. This can lead to a build-up of fluid and pressure in the eye and can damage the optic nerve.

It's often unclear exactly what causes it, although there are some things that can increase your risk, including:

  • your age – glaucoma becomes more likely as you get older and the most common type affects around 1 in 10 people over 75
  • your ethnicity – people of African, Caribbean or Asian origin are at a higher risk of glaucoma
  • your family history – you're more likely to develop glaucoma if you have a parent or sibling with the condition

It's not clear whether you can do anything to prevent glaucoma, but having regular eye tests will help ensure it's picked up as early as possible.

Read more about the causes of glaucoma.

Tests for glaucoma

Glaucoma can usually be detected during a routine eye test at an opticians, often before it causes any noticeable symptoms.

You should have a routine eye test at least every two years. Find out if you're eligible for free NHS eye tests.

Several quick and painless tests can be carried out to check for glaucoma, including measurements of the pressure inside your eye and tests of your peripheral vision.

If tests suggest you have glaucoma, you should be referred to an ophthalmologist (eye doctor) to discuss treatment.

Read about how glaucoma is diagnosed.

Treatments for glaucoma

It's not possible to reverse any loss of vision that occurred before glaucoma was diagnosed, but treatment can help stop your vision getting any worse.

The treatment recommended for you will depend on the type of glaucoma you have, but the main treatments are:

  • eye drops – to reduce the pressure in your eyes
  • laser treatment – to open up the blocked drainage tubes in your eyes or reduce the production of fluid in your eyes
  • surgery – to improve the drainage of fluid from your eyes

You'll also probably need regular appointments to monitor your condition and ensure treatment is working.

Read more about how glaucoma is treated.

Outlook for glaucoma

The outlook for glaucoma largely depends on the type of glaucoma you have, but generally:

  • it often results in some degree of permanent vision loss, although most people retain useful vision for life
  • it may affect your ability to do certain tasks, such as driving
  • only a small proportion of people will end up totally blind

The outlook is better the earlier glaucoma is diagnosed and treated.

This is why it's so important to get your eyes tested regularly and to make sure you follow your recommended treatment plan.

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There are several different types of glaucoma, which can have different symptoms, causes and treatments.

The main types include:

Primary open angle glaucoma

Primary open angle glaucoma, sometimes called chronic open angle glaucoma, is the most common type.

In this type of glaucoma, the part of the eye where fluid drains away (called the "angle") isn't blocked, but the fluid doesn't drain properly. This leads to increased pressure in the eye.

The condition usually develops very slowly over many years and doesn't cause any noticeable symptoms at first.

People often don't realise they have it because the outer areas of vision (peripheral vision) are affected first. Without treatment, vision towards the centre of the eye may also be lost.

Primary open angle glaucoma is usually picked up during a routine eye test, which you should have at least every two years. Visit an opticians or your GP if you're worried about any changes in your vision.

Primary angle closure glaucoma

Primary angle closure glaucoma is a less common type that occurs when the part of the eye that drains fluid becomes blocked, causing pressure to build up in the eye.

It occasionally develops slowly over time, but often it causes sudden, severe symptoms.

Symptoms can include:

  • intense eye pain
  • a red eye
  • headache
  • tenderness around the eyes
  • seeing halos or "rainbow-like" rings around lights
  • blurred vision
  • feeling and being sick

Sometimes these symptoms may last for a few hours before disappearing.

If you experience sudden symptoms, go to your nearest accident and emergency (A&E) department as soon as possible. This is a medical emergency that may require immediate treatment.

Secondary glaucoma

Secondary glaucoma is an uncommon type of glaucoma caused by another eye problem.

Causes include uveitis (inflammation of the middle layer of the eye), eye injuries and certain treatments, such as medication or operations.

The symptoms can vary considerably, and may include:

  • gradual loss of peripheral vision
  • blurred vision
  • seeing halos or "rainbow-like" rings around lights
  • eye pain
  • a red eye

Visit an opticians or your GP if you're worried about any changes in your vision. Go to your nearest accident and emergency (A&E) department as soon as possible if you have severe symptoms that occurred suddenly.

Childhood glaucoma

Childhood glaucoma, also called congenital or developmental glaucoma, is a type of glaucoma that affects babies and young children.

It's usually the result of a problem in the development of the eyes, which causes fluid and pressure to build up inside them.

Spotting the condition can be difficult, but your child may have some of the following symptoms:

  • larger eyes than usual
  • dislike of bright lights
  • uncontrollable blinking
  • red, watery or cloudy eyes
  • rubbing their eyes frequently

Visit an opticians or your GP if you notice any of these symptoms in your child.

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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.

Increased risk

Things that can increase your risk of developing glaucoma include:

  • age – glaucoma becomes more likely as you get older; the most common type (primary open angle glaucoma) affects up to 2 in 100 people over 40 and around 10 in 100 people over 75
  • ethnic origin – people of African, Afro-Caribbean or Asian origin are at increased risk of developing certain types of glaucoma
  • family history – if you have a close relative, such as a parent, brother or sister who has glaucoma, you're at increased risk of developing it yourself
  • other medical conditions – conditions such as short sightedness, long-sightedness and diabetes can increase your risk of glaucoma

Known causes

In a small number of cases, a cause for glaucoma is found.

Possible causes include:

  • a build-up of deposits in the drainage tubes in the eye – a common example is a condition called pseudoexfoliation glaucoma
  • new blood vessels growing inside the eye that block the drainage of fluid
  • uveitis (inflammation of the middle layer of the eye)
  • long-term use of steroid eye drops
  • eye injuries or previous eye surgery
  • a problem with the way the eyes developed – this can cause glaucoma in babies and young children
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Glaucoma is usually picked up during a routine eye test, often before it causes any noticeable symptoms.

It's important to have regular eye tests so problems such as glaucoma can be diagnosed and treated as early as possible. Early treatment can help stop your vision becoming severely affected.

You should have an eye test at least every two years. If you're at a higher risk of glaucoma, for example if you have a close relative with it, you may be advised to have more frequent tests.

You can get an eye test at a local opticians. Find an opticians near you.

Some people can receive free eye tests on the NHS. Find out if you're entitled to free NHS eye tests.

Tests for glaucoma

There are several quick and painless tests that can be carried out to diagnose and monitor glaucoma.

Eye pressure test

An eye pressure test (tonometry) uses an instrument called a tonometer to measure the pressure inside your eye.

A small amount of anaesthetic (painkilling medication) and dye is placed onto the front of your eye. A light from the tonometer is gently held against your eye to measure the pressure inside.

High pressure in your eye can be a sign that you have glaucoma or are at increased risk of developing it.


Gonioscopy is an examination of the front outer edge of your eye, between the cornea (transparent layer at the front of your eye) and the iris (the coloured part of your eye).

This is the area where the fluid should drain out of your eye.

A gonioscopy can help to determine whether this area (called the "angle") is open or closed (blocked), which can affect how fluid drains out of your eye.

Visual field test

A visual field test – sometimes called perimetry – checks for missing areas of vision.

You may be shown a sequence of light spots and asked which ones you can see. Some dots will appear in your peripheral vision (around the sides of your vision), which is often affected by glaucoma to begin with.

If you can't see the spots in your peripheral vision, it may indicate the glaucoma has damaged your vision.

Optic nerve assessment

The optic nerve (the nerve connecting your eye to your brain) can become damaged in glaucoma, so an assessment may be carried out to see if it's healthy.

For the test, eye drops will be used to enlarge your pupils. Your eyes are then examined with a slit lamp (a microscope with a bright light) to assess your optic nerve.

The eye drops used to widen your pupils could temporarily affect your ability to drive, so you'll need to make arrangements for getting home after your appointment.

Optical coherence tomography

Optical coherence tomography (OCT) is a type of scan where special rays of light are used to scan the back of your eye and produce an image of it.

This can help detect any damage to the retina (the light sensitive layer at the back of the eye) or optic nerve caused by glaucoma.

Referral to a specialist

If glaucoma is picked up during an eye test, you should be referred to an ophthalmologist (eye doctor) for further tests.

Your ophthalmologist will confirm your diagnosis and find out:

  • how far the condition has developed
  • how much damage the glaucoma has done to your eyes
  • what may have caused the glaucoma

He or she will then be able to advise on treatment. See treating glaucoma for more information.

In some cases, your ophthalmologist will continue to treat you. But for less serious types of glaucoma, you may be referred back to the opticians for your treatment.

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There are several different treatments for glaucoma, including eye drops, laser treatment and surgery. The best treatment for you will depend on your circumstances.

Treatment can't reverse any loss of vision that has already occurred, but can help stop your vision getting any worse.

This section covers:

Your treatment plan

Your treatment largely depends on which type of glaucoma you have.

For example:

  • primary open angle glaucoma is usually treated with eye drops, or laser treatment or surgery if drops don't help
  • primary angle closure glaucoma often needs immediate treatment in hospital with medication to reduce the pressure in the eye, often followed by laser treatment
  • secondary glaucoma may be treated with eye drops, laser treatment or surgery, depending on the underlying cause
  • childhood glaucoma often requires surgery to correct the problem in the eye that led to the build-up of fluid and pressure

You will also often be advised to attend regular follow-up appointments to monitor your eyes and check that treatment is working. It's important not to miss any of these appointments.

The main treatments are described below.

Eye drops

Eye drops are the main treatment for glaucoma.

Types of eye drops

There are several different types that can be used, but they all work by reducing the pressure in your eyes.

The main types of eye drops are:

  • prostaglandin analogues, such as latanoprost, bimatoprost, tafluprost and travoprost
  • beta-blockers, such as betaxolol hydrochloride, levobunolol hydrochloride and timolol
  • carbonic anhydrase inhibitors, such as brinzolamide and dorzolamide
  • sympathomimetics, such as brimonidine tartrate
  • miotics, such as pilocarpine

Eye drops can cause unpleasant side effects, such as eye irritation, and some aren't suitable for people with certain underlying conditions.

You may need to try several types before you find the one that works best for you. Sometimes you may need to use more than one type at a time.

Using eye drops

Eye drops are normally used between one and four times a day.

It's important to use them as directed, even if you haven't noticed any problems with your vision, because your sight is at risk if you don't stick to your recommended treatment.

To use eye drops:

  • use your finger to gently pull down your lower eyelid
  • hold the bottle over your eye and allow a single drop to fall into the pocket you have created in your lower lid
  • close your eye and keep it closed for a few minutes

If you're using two different types of eye drops, allow at least five minutes between using the different types.

Laser treatment

If eye drops don't improve your symptoms, laser treatment may be recommended.

This is where a high-energy beam of light is carefully aimed at part of your eye, to stop fluid building up inside it.

Types of laser treatment include:

  • laser trabeculoplasty – a laser is used to open up the drainage tubes within your eye, which allows more fluid to drain out of your eye and reduces the pressure inside it
  • cyclodiode laser treatment – a laser is used to destroy some of the tissue in the eye that produces aqueous humour (the liquid inside the eye), which can reduce pressure in the eye
  • laser iridotomy – a laser is used to create holes in your iris (coloured part of the eye) to allow fluid to drain from your eye

Laser treatment is usually carried out while you're awake. Local anaesthetic drops are used to numb your eyes, although you may feel a brief twinge of pain or heat during the procedure.

You may still need to use eye drops after having laser treatment.


Surgery may be recommended as an alternative to laser treatment in some cases.

Types of glaucoma surgery include:

  • trabeculectomy – the most common type of operation, it involves removing part of the eye drainage tubes to allow fluid to drain more easily
  • trabeculotomy – similar to a trabeculectomy, but an electric current is used to remove a small part of the eye drainage tubes
  • viscocanalostomy – an operation to remove part of the sclera (the white outer covering of the eyeball), so fluid can drain from your eye more easily
  • deep sclerectomy operation – an operation to widen the drainage tubes in your eye, sometimes by implanting a tiny device inside them
  • trabecular stent bypass – an operation to place a tiny tube into your eye to increase the drainage of fluid

Glaucoma surgery may be carried out under local anaesthetic (where you're awake) or general anaesthetic (where you're asleep).

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Selected links

NHS Direct Wales links

Cataract surgery

Double vision

Macular degeneration


Search local services: Opticians

External links

Understanding glaucoma (Royal National Institute for the Blind (RNIB)

Glaucoma (Moorfields Eye Hospital)

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The information on this page has been adapted by NHS Wales from original content supplied by NHS Choices.
Last Updated: 11/10/2016 09:22:33