Glaucoma

a close-up of an eye with a blue and gold iris

We’re funding glaucoma research studies to help diagnose and treat glaucoma more effectively, because we believe that people’s sight matters.

What is glaucoma?

Glaucoma is the name given to a group of eye conditions in which the optic nerve is damaged where it leaves the eye. There are three main types of glaucoma: primary, secondary and developmental (or congenital). It’s one of the most common causes of blindness worldwide.

10% Ten per cent of people in the UK who go blind do so due to glaucoma.

1,000,000 Over one million people in the UK have glaucoma–that’s 3% of everyone over the age of 40.

Causes of glaucoma

The optic nerve carries signals from the eye to the brain and allows you to see. Any damage to the optic nerve therefore prevents those signals from reaching your brain, which results in sight loss. Usually, this is caused by increased pressure inside the eye.

The eye is full of fluid, which helps it keep its shape and function properly. However, if too much fluid builds up inside the eye, the pressure rises.

If the pressure inside the eye gets too high, it squeezes the optic nerve. This causes some of the cells that make up the optic nerve to die, leading to sight loss. The optic nerve is very sensitive and can be easily damaged by even small increases in pressure inside the eye.

Pressure might build up inside the eye because:

fluid is blocked from draining away;
excess fluid is produced following an eye injury or infection (‘secondary’ glaucoma);
due to an abnormality in the shape of the eye in children (‘developmental’ or‘congenital’ glaucoma).

High pressure inside the eye is the most common cause of glaucoma, and it is most common in older adults (70+ years old), although it can affect anyone of any age. However, in rare cases, the optic nerve can be damaged without a raised pressure inside the eye (‘normal pressure glaucoma’).

Signs and symptoms of glaucoma

Glaucoma tends to develop slowly over many years, and normally affects peripheral vision first, causing ‘tunnel vision’. If untreated, it can cause blindness.

Vision lost to glaucoma cannot be recovered, so it’s essential to diagnose it early and monitor it carefully to prevent as much vision loss as possible.

Types of glaucoma

Glaucoma isn’t a single disease. It refers to several distinct types of eye conditions that share one outcome — damage to the optic nerve, leading to sight loss. Understanding which type someone has helps us research better ways to diagnose, monitor and treat.

There are five types of glaucoma:

Primary open-angle glaucoma: This is the most common form. Here, the drainage angle inside the eye remains open, but fluid (aqueous humour) drains too slowly. Over time this causes the pressure inside the eye to rise and leads to optic nerve damage. Because it develops gradually and without pain, many people are unaware they have it until vision is affected.
Primary angle-closure (closed-angle) glaucoma: In this type, the drainage angle becomes very narrow or is blocked altogether, preventing fluid from escaping. This can trigger a sudden and steep rise in intra-ocular pressure — an emergency that needs urgent attention. There is a slower, chronic form too, but the risk of rapid vision loss makes it particularly serious.
Normal-tension (low-pressure) glaucoma: In some people the optic nerve is damaged even though the eye-pressure remains within the ‘normal’ range. It suggests other factors (for example, reduced blood flow to the nerve or nerve-vulnerability) play a role. Because the pressure may appear normal, this type demands careful specialist assessment.
Secondary glaucoma: This refers to glaucoma that develops because of another eye condition, injury, medication or disease that affects the eye’s drainage system. Examples include inflammation inside the eye (uveitis), trauma, long-term use of steroids, or the growth of abnormal blood vessels (neovascular glaucoma). In research terms, this category encourages study not just of pressure and drainage, but of the underlying triggers.
Congenital and developmental glaucoma: Present in babies or very young children, this form arises because the drainage system of the eye did not develop normally. Signs may include sensitivity to light, excessive tearing, a cloudy cornea or an unusually large eye. Early detection and specialist surgical care are essential — and it’s an important focus for paediatric research.

Can glaucoma be cured?

It is not possible to repair the optic nerve once it is damaged, so any vision lost to glaucoma cannot be recovered.

Treatment for glaucoma therefore focuses on early diagnosis and careful monitoring of patients, and regular treatment (with eye drops, laser treatment or surgery) to reduce the pressure inside the eye and prevent further damage to the optic nerve. This helps prevent further sight loss.

9 out of 10

people with glaucoma who get treatment will not go blind and will retain useful sight for the rest of their life.

There are usually no symptoms of a rising pressure in the eye until sight loss occurs, so regular eye tests are the best way to help spot the condition early.