Glaucoma - being a glaucoma suspect

Glaucoma is a condition in which there is damage to the optic nerve, which 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, causing the pressure inside the eye to rise. Some people can get glaucoma with a normal pressure as well.

In the early stages of glaucoma, most people have no symptoms. If it is left untreated, glaucoma can lead to severe loss of vision, or even blindness. It is a leading cause of irreversible blindness in the UK and 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 the visual function and lead to permanent and irreversible loss of vision. In most cases, diagnosing the condition early and treating it effectively can avoid blindness.

What being a ‘glaucoma suspect’ means

If you have been diagnosed as a 'glaucoma suspect' patient, this means you do not definitely have glaucoma, but you have some features that might indicate you are at risk of developing it. 

This could mean that:

  • the state of your optic nerve might indicate glaucoma
  • your visual fields (area of vision) are decreased
  • there is raised pressure in your eye (a major risk factor for glaucoma)
  • you have a family history of 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 vary in appearance from one person to another. This means it is sometimes difficult to know if someone’s optic nerve is normal or abnormal.

If the appearance of the nerve does not change over time, it is likely that it is normal for you. If there is a change, it might suggest a condition that is getting worse, like glaucoma.

Ways the optic nerve might suggest glaucoma


Short-sighted (high myopic) patients have larger eyeballs than others. Their optic nerves can look like they are damaged, but this might just 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, so from the top, they look tilted. This can make it 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 abnormal, it might be the normal appearance for that optic nerve.

Asymmetric (non-matching) discs

Occasionally patients look like they have 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. They take a while to do properly and to understand. There is usually a learning curve. This means visual field test performance can get better over time. There are factors, other than glaucoma, that can cause a defect in your visual field. This includes your glasses prescription, tilted discs, your upper lid coming down during the test, and other eye and optic nerve conditions.

Next steps

We will 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 detect any subtle changes
  • eye pressure checks
  • visual field tests to make sure your area of vision is not reducing

If there is a detectable change in the appearance of your optic nerve, We will discuss this with you and consider treatment, further testing or observation. If after 2 to 3 years there is no change, we will usually discharge you back to the care of your local optician.

We recommend that your optician should continue to observe the eye pressure, the optic nerve and visual fields every 1 to 2 years, 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 provide help and support to everyone affected by sight loss from glaucoma. 


Resource number: 4147/VER3
Last reviewed: August 2022
Next review due: August 2025 

Contact us

If you have any questions about your condition or treatment plan, please call our glaucoma call-back service and leave a message.

Phone: 020 7188 9121

We aim to respond to all phone calls within 2 days (excluding weekends and bank holidays). 

Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

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