Overview

Glaucoma is a condition where there is damage to the optic nerve. This is the nerve that carries visual signals from the eye to the brain.

Damage is usually caused by a build-up of fluid (aqueous humour) in the eye. This causes the pressure inside the eye to rise. Some people can get glaucoma with a normal pressure inside the eye.

In the early stages of glaucoma, most people have no symptoms. However, if it is left untreated, glaucoma can lead to severe loss of vision or even blindness.

Glaucoma is a leading cause of irreversible blindness in the UK and around the world. When about half of the optic nerve is damaged, the field of vision (the area you can see) starts to be affected. If left untreated, this can affect how the eye works and lead to permanent loss of vision that cannot be reversed.

In most cases, diagnosing glaucoma early and treating it effectively can avoid blindness.

What being a glaucoma suspect means

If you have been diagnosed as a glaucoma suspect, this means that you do not definitely have glaucoma. However, there are some signs that might show you are at risk of getting it. 

This could mean that:

• the appearance of your optic nerve might suggest glaucoma
• your visual fields (area of vision) are decreased
• there is raised pressure in your eye (a big risk factor for glaucoma)
• OCT (optical coherence topography) scans of your central retina or optic nerve are abnormal

You might have a combination of these factors. 

Optic nerve

The optic nerve can have a slightly different appearance for each person. This means that it is sometimes difficult to know if someone’s optic nerve is normal or abnormal.

If the appearance of the nerve does not change with time, it is likely that it is normal for you. If there is a change, it will suggest a progressive condition like glaucoma.

Ways the optic nerve might suggest glaucoma

This section explains how the appearance of the optic nerve might suggest glaucoma.

Short-sightedness (myopia)

People who are short-sighted (high myopic) have larger eyeballs than others. Their optic nerves can look like they are damaged, but this might be normal for you.

Tilted optic nerve head

Sometimes, the optic nerve can enter the back of the eyeball at an angle rather than straight. The optic nerve then looks tilted from the top.

It can look like the tilted side of the optic nerve head is thinner than the rest of the nerve. The optic nerve head is the beginning of the optic nerve that is visible at the back of the eye. While this may look unusual, it might be the normal appearance for that optic nerve.

Asymmetric (non-matching) discs

Sometimes, it can seem that there is a bigger optic nerve head at the back of one eye compared with the other. This can make it look like the larger optic nerve head has fewer nerve fibres than the smaller one. This might be correct, or it might be the normal appearance for that optic nerve.

Some reasons why visual fields may be abnormal

The visual field test measures how much area of vision each eye has. The tests take a while to do properly and to understand.

There is usually a learning curve. This means that your performance in the visual field test can get better with time. There are things other than glaucoma that can cause a defect in your visual field. They include:

• your glasses prescription,
• tilted discs
• your upper lid coming down during the test
• other eye and optic nerve conditions

Next steps

We monitor the appearance of your optic nerves regularly by:

• examination of your eyes with specialised instruments and lenses
• photographs or OCT scans of the nerve at the back of your eyes to help find any subtle changes
• eye pressure checks
• visual field tests to make sure that your area of vision is not reducing

If we notice a change in the appearance of your optic nerve, we will talk to you about the possible options. These may include:

• treatment
• more testing
• observation

If after 2 to 3 years there is no change, we will usually arrange for you to go back to your local optician's care.

We recommend that your optician continues to observe the eye pressure, the optic nerve and visual fields every 1 to 2 years. They can do this as part of your routine eye tests.

If we do diagnose glaucoma, it can be treated by daily eye drops, laser treatment, surgery, or a combination of these treatments to reduce the eye pressure.

Support and more information

Glaucoma UK gives help and support to everyone affected by sight loss from glaucoma. 

Website: www.glaucoma.uk