Glaucoma is a group of eye diseases that damage the optic nerve. It often affects both eyes, usually to varying degrees. As most cases won’t have any symptoms, one of the best ways to detect glaucoma is during a routine eye test – that’s why it’s so important to have one regularly.

What causes glaucoma?

The eyeball contains a fluid called aqueous humour, which is constantly produced by the eye. Any excess fluid is drained from the eye through tiny channels and tubes. When the fluid cannot drain properly, pressure builds up in the eye.

Glaucoma typically develops when this increased pressure damages the optic nerve, which connects the eye to the brain, and harms the nerve fibres from the retina, the light-sensitive nerve tissue that lines the back of the eye.

In acute glaucoma cases this pressure rises rapidly to higher levels, even causing pain.

Risk factors of glaucoma

Anyone can develop glaucoma, but there are several risk factors which make developing it more likely.

  • You have at least a four-times higher risk of developing glaucoma if you have a close blood relative who has it
  • Age plays a big part; chronic glaucoma affects up to two in every 100 people over 40 and around five in every 100 people over 80
  • Higher levels of short sightedness are linked to the chronic form of glaucoma and long-sighted people to the acute form
  • Consistently raised pressure in the eye is a warning sign, this is called ocular hypertension (OHT)
  • People of African-Caribbean origin have about a four-times higher risk of chronic forms of glaucoma compared to those of European origin
  • Acute glaucoma is 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
  • People with diabetes may be at higher risk of developing glaucoma
  • Very high blood pressure can lead to an increase in intraocular pressure.
  • Low blood pressure can lead to insufficient blood supply to the optic nerve which can also cause problems

The types of glaucoma

The main types of glaucoma are as follows, but you’ll find much more in our guide to glaucoma diagnosis.

Chronic open-angle glaucoma/primary open angle glaucoma

Chronic or primary open-angle glaucoma is the most common type of glaucoma. It develops gradually and painlessly, so an eye test is usually the only way to detect it.

Primary angle-closure glaucoma

Sometimes known as acute glaucoma, primary angle-closure glaucoma is usually treated as a medical emergency. 

Unlike chronic open-angle glaucoma, primary angle-closure glaucoma happens quickly due to a sudden rise in eye pressure and can lead to sight loss if not treated quickly.

Hereditary glaucoma

There is at least a four-times higher risk of developing glaucoma if you have a close blood relative who has it.

Congenital glaucoma

Congenital means a condition is present at birth and it does affect a very small number of babies.

Traumatic glaucoma

Traumatic glaucoma can develop after an eye injury to the eye – either a blunt trauma or something that penetrates the eye. It can happen at the time of the injury or later.

What are the symptoms of glaucoma?

There are various types of glaucoma and symptoms will differ depending on which type you have.

If you have chronic glaucoma, you might not realise you have it because it’s painless and affects your peripheral (outer) vision. Without regular checks you may not notice there’s a problem until your start to lose your more central vision.

Acute glaucoma develops much faster as a result of sudden pressure build-up in the eye. Although rare, it is usually painful and is often accompanied by:

  • Blurred vision
  • Haloes around lights
  • Headache
  • A red eye
  • Nausea/vomiting

If you get these symptoms, it is important to seek immediate assistance. Contact your optician or local accident and emergency department.

Even if the symptoms go away you should contact your optician as soon as possible as repeat episodes can cause damage to your eyesight.

Diagnosing glaucoma

Glaucoma will usually be diagnosed during a normal eye test. As well as looking at the overall health of your eye and the structures within it, you’ll also have a series of quick and painless tests that help to spot any signs of glaucoma.

Tests for glaucoma

Eye pressure test (tonometry)

An instrument called a tonometer is used to measure the pressure inside your eye – intraocular pressure.

Tonometry can be useful to identify ocular hypertension (OHT – raised pressure in the eye), which is a risk factor for chronic open-angle glaucoma.

Visual field test

You will be shown a sequence of light spots and asked which ones you can see. Some dots will appear in your peripheral vision, which is where glaucoma begins.

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

Optic nerve assessment

Your optic nerve connects your eye to your brain. This can be assessed in a variety of ways during your examination and it is also photographed using a retinal camera. Digital retinal photography (DRP) captures an image of your optic nerve which can be used as reference for future visits and to track any changes that may occur over time.

OCT (Optical Coherence Tomography)

OCT scans are similar to MRI and ultrasound scans and can help our opticians detect signs of glaucoma and other conditions up to four years earlier than more traditional imaging methods. The scan produces a 3D-like image that allows us to see the structures of your eye in even greater detail. Over time, your optician will be able to spot the changes that indicate the start of glaucoma. Ask your local store if they offer OCT and you can add it to your eye test.

Our partners


We work closely with the charity Glaucoma UK to help raise awareness of glaucoma and avoid preventable sight loss caused by the disease.

Our collaborations have included specialist glaucoma training for Specsavers colleagues so our teams can help people with glaucoma manage their condition – specifically helping people use eye drops.

What is Glaucoma UK?

Glaucoma UK is the only charity specialising in glaucoma in the UK. Over 700,000 people in the UK have glaucoma. Half of them don’t know they have it. Glaucoma UK want to change this and end needless glaucoma sight loss. The charity:

  • Campaigns to raise awareness of glaucoma so it is detected early and can be treated
  • Supports people to live well with glaucoma
  • Funds sight-saving research.

Part of Glaucoma UK’s mission is to ensure that people with glaucoma receive the information, advice and support they need to manage their condition well. Therefore, they work closely with eye health professionals, including ophthalmologists (eye doctors), optometrists and ophthalmic nurses, for example to provide training and produce resources as well as involving them in the governance of Glaucoma UK. Glaucoma UK recently formally incorporated the UK and Éire Glaucoma Society, a society for professionals working in glaucoma, meaning even closer links between the charity and eye care professionals.

As a charity, they are reliant on the kindness and generosity of supporters.

Glaucoma UK provides services including:

  • A free telephone helpline (weekdays, 9.30am – 5.00pm – call 01233 64 81 70 or email
  • Free information resources available on the website and through hospitals, opticians, and GP surgeries
  • Glaucoma support groups
  • Organising Glaucoma Awareness Week and supporting other campaigns to raise awareness of glaucoma and eye health
  • Working in partnership with UK and European organisations to prioritise eye health, vision and glaucoma. This includes other charities, professional bodies such as the Royal College of Ophthalmologists, and the DVLA.

Glaucoma UK also works jointly with the following organisations to provide research funding into the treatment, management, and detection of glaucoma:

  • Royal College of Ophthalmologists
  • College of Optometrists
  • Royal College of Nursing
  • Fight for Sight

Glaucoma treatment

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.

So regular eye tests are essential. You should have an eye test at least every two years or more frequently if advised by your optometrist. For example, they may suggest you have more frequent eye tests if you have a close relative with glaucoma, such as a parent, brother or sister.

If your optometrist suspects glaucoma, you will be referred to an ophthalmologist for further tests. If the ophthalmologist confirms a diagnosis of glaucoma, they will also be able to explain:

  • How far the condition has developed
  • How much damage the glaucoma has had on your eyes
  • What may have caused the glaucoma

They will then be able to advise on treatment which in most cases is simply an eye drop used on a daily basis coupled with regular follow-up appointments.

Drops may be used to examine your eyes in a glaucoma appointment – these can temporarily affect your vision. Please check when making the appointment if you will be able to drive immediately after the appointment.

Eye drops

The purpose of the eye drops is to lower the eye pressure either by reducing the amount of fluid (aqueous humour) that is produced or helping it to drain better from the eye.

Laser treatment

Depending on the type of glaucoma, different types of laser treatment could be used. In an acute case, a procedure called an iridotomy is often used to quickly relieve the pressure and keep it lower. In non-acute cases, a selective laser trabeculoplasty (SLT) can be used to help lower the pressure, it is especially useful for people with open-angle glaucoma that hasn’t got any better using eye drops to lower the pressure. 


Eye drops will often be the first treatment to try, but surgery is an option. Trabeculectomy surgery helps to slow the development of glaucoma and lower eye pressure, many other procedures may be used dependent on the stage and type of glaucoma.

Future treatment options

There are new treatments in the pipeline for glaucoma. These include a tiny stainless-steel device which allows fluid to drain out of the eye, a little probe which travels through a tiny incision and uses thermal energy to improve drainage, and a treatment called canaloplasty which uses an extremely fine catheter to enlarge the eye’s natural drainage canal and relieve pressure inside the eyes. The benefits of all these treatments include the fact that they are minimally invasive, thereby reducing pain and side effects.

Researchers are also looking at new ways to combine eye drops to make them work better and easier to use. In the longer term, research is being done into treating brain and nerve tissue to help it regenerate, as well as investigating how stem cells can help protect the optic nerve.

For more information on understanding how glaucoma is treated, head across to our dedicated treatment hub where you can learn more about eye drops, as well as other treatment options.

Learn more about glaucoma in our information hub

As part of our mission to help end avoidable sight loss, we’ve put together some helpful information about everything glaucoma – from its causes, how it’s diagnosed, and how it can be treated.