Glaucoma

What is glaucoma?

Glaucoma is a group of conditions in which pressure builds up in the eye. In healthy eyes, the eye continuously produces watery fluid, which drains away through tiny channels, but when you have glaucoma, there is something stopping the fluid from draining away.

The build-up of pressure in the eye causes damage to the eye, especially the optic nerve.

What are the different types of glaucoma?

These are the five main types of glaucoma:

Primary open angle glaucoma 

Your eyes continuously produces watery fluid - in healthy eyes this drains away in the “angle” between the iris and the cornea, through sponge-like tissue (the trabecular meshwork). In primary open angle glaucoma, the "angle" is open but gaps in the sponge-like tissue get narrower or are blocked by deposits.

This means that the fluid can't drain away properly. You might not get any symptoms until it is quite advanced, when it starts to affect the peripheral vision. As it progresses it can eventually lead to blindness.

Primary open angle glaucoma (POAG) is the most common form of glaucoma.

Acute angle closure glaucoma

Acute angle closure glaucoma, also known as closed angle glaucoma or narrow angle glaucoma, happens when eye pressure rises very suddenly, which can lead to serious damage to the optic nerve, causing blindness. It happens when the drainage angle in the eye is blocked by the iris.

It’s a lot less common than primary open angle glaucoma. People of East Asian background and women tend to be at higher risk compared to other groups.  

Secondary glaucoma

Secondary glaucoma is glaucoma that is caused by (or “secondary to”) another eye condition, or eye injury, or as an effect of certain medications. Like other forms of glaucoma, it’s caused by raised pressure in the eye, and can lead to blindness if the optic nerve is damaged.

If the underlying problem causing the raised pressure is cured or corrected, the pressure may return to normal. But if the optic nerve is already damaged and you have sight loss as a result, this can’t be reversed.

Normal tension glaucoma (NTG)

Unlike other forms of glaucoma, in normal tension glaucoma the pressure is normal. It’s not fully understood, but it’s believed some people’s optic nerves may be more fragile, meaning that even a normal level of eye pressure is still too high and causes damage.

Because the eye pressure is at a normal level, it can be harder to spot during routine eye checks. There are usually no symptoms of NTG until it has become very advanced. It can affect the central vision earlier than other types of glaucoma.

Congenital glaucoma

Congenital glaucoma, also known as childhood glaucoma, is a condition you are born with. It means the eye hasn’t developed properly in the womb, with the result that the eye fluid can’t drain out of the eye. This causes pressure to build up, which can lead to permanent vision damage. 

Congenital glaucoma is a rare type of glaucoma. Symptoms include enlarged eyes, cloudiness of the cornea, and photosensitivity (sensitivity to light).

What causes glaucoma?

Glaucoma is usually caused by high pressure in the eye, because the fluid in the eye can’t drain away like it normally should. This leads to damage to the optic nerve – the nerve that connects the eyes to the brain - which can cause blindness. 

Age is the biggest risk factor for glaucoma. Having diabetes also puts you at higher risk. So does having a close relative, such as a parent or sibling, with glaucoma. People of Black African, Black Caribbean, Chinese or South Asian origin may be more at risk of certain types of glaucoma.

What are the signs and symptoms of glaucoma?

Glaucoma tends to develop slowly and often doesn’t cause noticeable symptoms until it's quite advanced and damage to the optic nerve has  has already happened.

When glaucoma does cause symptoms, these might include:

• Blurred and reduced vision, starting with peripheral vision (outer edges) which develops very slowly. 

• Seeing rings and rainbow-coloured circles around bright lights. 

• Symptoms of acute angle closure glaucoma are a bit different - it causes sudden severe eye pain and blurred vision. It might be accompanied by redness and tenderness of the eye and surrounding area, plus a headache, nausea and vomiting. 

Concerned about your eyesight or that of a loved one? Make an appointment today with an optician to get it checked out. Even if your vision seems fine, get your eyes tested every two years. An eye test can spot some eye conditions and early treatment might be able to stop them getting worse.

If you’re at risk of glaucoma, for example if you're over 40 and your mother, father, sibling, or child has glaucoma, you’re entitled to more frequent free eye tests on the NHS. 

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Is glaucoma serious?

Glaucoma doesn’t always cause symptoms, but as it goes on it can damage your vision and ultimately can lead to blindness. In fact it’s the leading cause of irreversible blindness. Acute angle closure glaucoma (narrow angle glaucoma) is particularly serious because it can cause blindness if not treated straight away.

How is glaucoma diagnosed?

Glaucoma is usually diagnosed following routine eye tests. Tests for glaucoma often start with an eye pressure test. An optometrist will also examine the front part of your eyes, to see whether they can spot any issues with fluid drainage, such as a blockage.

Visual field tests are also carried out to see whether you have lost any peripheral vision. The optic nerve will be assessed too. This sometimes involves eye drops or a scan of the eyes so the optometrist can get a closer look.

If glaucoma is suspected, you’ll be referred to a specialist to confirm the diagnosis and assess any damage that’s already occurred.

What are the treatments for glaucoma?

Treatment can't reverse sight loss that has already occurred, but it can help stop it getting any worse. Glaucoma is treated by managing the underlying causes to prevent further damage to the optic nerve. Your treatment plan will depend on the type of glaucoma, and other aspects of your health, but is likely to include laser treatment and/or eye drops. 

The main treatment options are:

Glaucoma eye drops

Eye drops for glaucoma work by either reducing the amount of fluid being produced in the eye, or by improving fluid drainage from the eye. There are several different types. Normally they need to be used between one and four times a day, and need to be taken long term. You may need to try several types before finding one that works best for you, or you may need to use more than one type. Eye drops can cause side effects, such as eye irritation, and some aren't suitable for people with certain other health conditions.

Laser treatment for glaucoma

Laser treatment can help improve fluid drainage and lower eye pressure. It’s done as an outpatient, using local anaesthetic to numb the eyes. You might feel a brief twinge of pain or heat during the procedure.

Trabeculectomy

This is a type of surgery that might be used where treatment with eye drops or lasers hasn't been effective - it's less common than the other treatments. A specialist surgeon will create a new drainage channel within the eye to improve fluid drainage. It is done as an outpatient procedure, under local anaesthetic.

Most people won't need to take eye drops any more after a trabeculectomy, and you shouldn't be in a lot of pain after surgery. However, the affected eye might water and be red after surgery, and vision may be slightly blurred for up to 6 weeks - this should return to normal.

What can help glaucoma?

There is no known way to stop glaucoma from developing, but there are ways that can help stop severe sight loss from glaucoma, including a healthy diet, exercise, and being cautious about use of steroid medication, which can raise eye pressure. Talk to your doctor if you have been prescribed steroids or steroid eye creams and you’re concerned about glaucoma.

Have your eyes tested every two years even if you think your vision is fine. An eye test can spot glaucoma and, if caught early, treatment may prevent further deterioration. If you have been advised that you are at risk of glaucoma (e.g. a close relative has the condition) you are entitled to more frequent free eye tests.

What research is there into glaucoma?

Sight loss from glaucoma is irreversible. We're dedicated to funding pioneering research to prevent glaucoma, improve early diagnosis and find new treatments. The research we fund will have a huge impact on those living with the condition.

We're funding glaucoma research projects across the UK. For example, researchers are finding treatments for glaucoma that will lower eye pressure and reduce damage to the parts of the eye that are responsible for vision.

Professor Keith Martin is leading a project, based at the University of Cambridge, which aims to strengthen the connection between the eye and the brain, protecting and regrowing the vital cells that are damaged by glaucoma and other conditions. Listen to Keith's podcast to find out more about his research into glaucoma.

James Morgan, Professor of Ophthalmology at Cardiff University, is studying the extent to which the immune system can accelerate the damage to retinal cells that connect the eye to the brain. Watch James's video below to find out more about his research.

Fight for Sight is currently funding a research project at UCL Institute of Ophthalmology investigating the effect of lifestyle factors – such as alcohol, smoking, exercise and diet – on the development of glaucoma. 

See our research projects