Glaucoma
Glaucoma is an eye condition usually caused by a build-up of fluid, leading to high pressure in the eye. This pressure can cause optic nerve damage. Early treatment is key to limiting the extent of sight loss with this common condition.
On this page
A diagram of a healthy eye with labels.
A diagram of an eye affected by glaucoma. Arrows show how pressure directed to the back of the eye damages the optic nerve. The diagram also shows how fluid builds up in the eye due to a blocked drainage canal.
Glaucoma symptoms and signs
Glaucoma tends to affect your peripheral (side) vision first, meaning you might not notice it in the early stages. Symptoms usually appear slowly, so many people aren’t aware they have the condition.
This is one reason why regular eye exams are so important. If you're over 40 and have a family history of glaucoma, you can get a free eye test on the NHS.
Speak to your GP or eye doctor about any changes in your vision, such as seeing rainbow-coloured circles around bright lights or blurred vision.
If you would prefer to watch the video without an audio description, there is a non-described version here rather than the accessible one above.
How long does it take to go blind with glaucoma?
Although the damage glaucoma causes can’t be reversed, a glaucoma diagnosis doesn’t have to mean you will lose your sight. The sooner it’s diagnosed, the sooner treatment can start to prevent further damage to the optic nerve and further loss of sight.
When glaucoma progresses and becomes more severe, it can result in 'tunnel' vision. It can also go on to affect central vision and the ability to see detail (visual acuity).
Glaucoma causes and definition
Glaucoma is defined as a condition caused by increased pressure in the eye, usually triggering slow loss of vision. This happens when fluid isn't able to drain away from the eye as it normally would. The build-up of pressure can also restrict blood flow to the optic nerve, which connects the eye to the brain, and it’s this that causes sight loss.
The specific cause depends on the type of glaucoma you have. Symptoms may not be noticeable, so routine eye tests are crucial to spotting it early enough to be treated effectively.
Who is at risk of glaucoma?
There are several risk factors that lead to an increased risk of developing glaucoma. These include:
- High eye pressure (known as intraocular pressure)
- A family history of the eye condition
- Diabetes, heart disease or high blood pressure
- Previous eye injury or eye surgery
- Ethnicity - some types of glaucoma are more common among people who are black or Asian
Types of glaucoma
There are several types of glaucoma. In most, symptoms develop slowly. This is because the pressure causing damage to the optic nerve is increasing gradually. However, if left untreated, glaucoma can result in vision loss.
Treating glaucoma
Glaucoma treatments aim to reduce the increased pressure in the eye. The damage caused by glaucoma can’t be reversed, but further damage can be prevented with treatment. This may include eye drops, laser treatment or surgery.
The right treatment can depend on the type of glaucoma you have but normally involves:
- Eye drops – these are taken regularly for a long time. They work to reduce the build-up of fluid and prevent any further sight loss.
- Laser treatment - involves carefully targeting a laser at part of the eye to stop fluid build-up.
- Surgery – in some cases, this might be considered. The most common operation for glaucoma is a trabeculectomy. This procedure creates a new channel in the eye that allows fluid to drain away, relieving pressure inside the eye.
When to get medical advice
If you’re at all worried about your vision, see an optician or your GP as soon as you can.
The NHS recommends having an eye test every two years. With regular eye examinations, you’re more likely to catch problems sooner, improve your eye health and get an early diagnosis of glaucoma or other eye diseases.
If the optician even suspects you have glaucoma, for example, after doing a visual field test, they’ll refer you straight to a specialist (usually an ophthalmologist) for more tests.
Frequently asked questions
Medically reviewed by: The Royal College of Ophthalmologists on 18/10/2022
Edited by: Nick Astbury FRCS FRCOphth FRCP
Clinical Associate Professor
LSHTM
The Royal College of Ophthalmologists champions excellence in the practice of ophthalmology and is the only professional membership body for medically qualified ophthalmologists. The RCOphth is unable to offer direct advice to patients. If you’re concerned about the health of your eyes, you should seek medical advice from your GP, optometrist or ophthalmologist.