Health A to Z
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.
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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:
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.
This is a medical emergency that may require immediate treatment.
There are several different types of glaucoma.
Some of the main types are:
Read more about the types 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:
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.
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.
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:
You'll also probably need regular appointments to monitor your condition and ensure treatment is working.
Read more about how glaucoma is treated.
The outlook for glaucoma largely depends on the type of glaucoma you have, but generally:
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.
There are several different types of glaucoma, which can have different symptoms, causes and treatments.
The main types include:
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 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:
Sometimes these symptoms may last for a few hours before disappearing.
If you experience sudden symptoms, go to your nearest eye casualty unit or accident and emergency (A&E) department as soon as possible. This is a medical emergency that may require immediate treatment.
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:
Visit an opticians or your GP if you're worried about any changes in your vision. Go to your nearest eye casualty unit or accident and emergency (A&E) department as soon as possible if you have severe symptoms that occurred suddenly.
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:
Visit an opticians or your GP if you notice any of these symptoms in your child.
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:
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.
There are several quick and painless tests that can be carried out to diagnose and monitor glaucoma.
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.
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.
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 (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.
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:
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.
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.
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Your treatment largely depends on which type of glaucoma you have.
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 are the main treatment for glaucoma.
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:
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.
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:
If you're using two different types of eye drops, allow at least five minutes between using the different types.
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 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:
Glaucoma surgery may be carried out under local anaesthetic (where you're awake) or general anaesthetic (where you're asleep).
Linda Moore has had open angular glaucoma since she was 39. She runs the Poole Glaucoma Support Group, which supports people with glaucoma in their local area.
"I had no idea I had glaucoma until I went for a routine eye examination at the age of 39. I didn't have any symptoms at all, but after my eye test the optician just said: 'You've got early-stage glaucoma. I'm going to give you a letter to give to your doctor, and you'll need to see a consultant.'
"It was a shock to find out there was something wrong. I know now that I've got a family history – one of my aunts had it – but at the time I didn't know anything about it. I was aware that it's a disease of the eye, but I didn't realise it could cause blindness.
"To be honest, when I saw the consultant I wasn't given much more information. I received some eye drops (glaucoma causes the tear ducts to dry up, so the drops help with that). I was told I'd have to take them for the rest of my life, but that was it. I've discovered through the support group that many people find there's a lack of information during the first consultant appointment.
"One of the major causes of glaucoma is a rise in the pressure in your eye, which weakens the optic nerve and possibly damages it. At one point, the pressure in my eyes kept rising and I was advised to have laser treatment to lower it. The treatment took place at the Eye Unit at Bournemouth Hospital. It wasn't particularly comfortable or painless, but it was over quickly, and it worked.
"I know I've been very lucky. I've had good consultants who've kept a careful watch on the results of my six-monthly check-ups, and I've managed to maintain reasonable eyesight. I've had to stop giving blood, and I can't take certain medications – but they're the only restrictions so far. My eyes are tested regularly, and I need new glasses every two years. But having regular eye tests is absolutely crucial. I know of people whose eyesight got worse almost overnight due to their glaucoma being undiagnosed or unchecked."