About glaucoma

The name glaucoma is actually used to describe not just one eye condition but a group of eye conditions that affect your vision. What they all have in common is that in each case there's damage to the optic nerve - the nerve at the back of the eye that sends information from your eye to your brain.

What usually happens is that the drainage tubes within the eye become slightly blocked. This stops the natural eye fluid from draining away properly.

When this fluid can’t fully drain, pressure inside the eye, known as intraocular pressure (IOP) builds up and stops the optic nerve from getting enough blood. As the nerve becomes damaged, the eye becomes less sensitive to light.

Glaucoma often affects both eyes but one eye may be more quickly than the other.

If it isn’t treated, glaucoma can have serious consequences and even cause blindness. But provided it’s diagnosed and treated early enough, further damage to your vision can be prevented.

See how much you know already about glaucoma by taking our quick quiz.

How much do you know already?

What are the three greatest risk factors for glaucoma?

Age, family history and ethnic origin. You are at risk of glaucoma if you are over 40, you have at least one close blood relative with glaucoma or you are of Afro-Caribbean or Asian origin.
What is the most important cause of glaucoma?

High eye pressure.
How common is glaucoma?

Glaucoma affects around 480,000 people in England alone; however, some groups are more prone to it then others. Among white Europeans open-angle glaucoma is present in around 1 in 50 people over 40 years old and around 1 in 10 people over 75 years old. It may be more common in people of black-African or black-Caribbean origins.
Are there different forms of glaucoma?

Yes, there several types of glaucoma. The most common form is primary open angle glaucoma, a chronic progressive disease causing damage to the main nerve at the back of your eye.
How is glaucoma diagnosed?

A group of three tests carried out by optometrists to detect glaucoma – called tonometry, perimetry and ophthalmoscopy – are designed to look at the condition of your eye and test the pressure inside it. They should be carried out every year on people at high risk of glaucoma.
Does glaucoma only affect older people?

No. Although the most common form of glaucoma tends to develop in people over the age of 50, younger people and even children can also get glaucoma.

Types of glaucoma

Altogether, there are several types of glaucoma but generally the condition falls into one of four main types. Whether or not you have symptoms, and how much your sight will be affected, depends on which type you have.

Primary open angle glaucoma

Also called chronic open angle glaucoma, this is the most common type of glaucoma in the UK. It comes on very slowly and mainly in people over the age of 50. It tends to develop without causing any pain or other symptoms. That’s why it’s easy to miss and why it’s important to visit your optician regularly.
Primary angle closure glaucoma

Also called closed angle glaucoma, this is a rare type of glaucoma and can happen slowly (chronic) or may come on rapidly (acute) with a sudden, painful build-up of pressure in the eye.
Secondary glaucoma

This form of glaucoma is caused by a sudden rise in eye pressure as a result of an eye injury or, sometimes, as the side effect of medication or an illness such as diabetes. Symptoms include pain, sealing halos around light sources and red eye.
Developmental glaucoma

This glaucoma can affect babies and children. Symptoms can include having large eyes, being sensitive to light, cloudy or watering eyes and poor vision or a squint.

Causes of glaucoma

Glaucoma is generally caused by a blockage in part of the eye which prevents fluid draining naturally out of the eye and in turn increases pressure in the eye. Although sometimes it is possible to have glaucoma with normal eye pressure.

How the eye works: The eyeball is filled with a fluid called aqueous humour, which creates pressure in the eyes to give it shape. In healthy eyes, this fluid constantly flows in and out of the eye. It drains back into the bloodstream at the same rate as it's produced, so keeping the pressure inside the eye at just the right level.

Glaucoma happens when the drainage tubes, known as the trabecular meshwork, inside the eye become blocked. The blockage stops the eye fluid from draining away as it should. And because the fluid can't get out, the pressure inside the eye builds up, damaging your sight over time.

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