Being a ‘glaucoma suspect’
What is glaucoma?
Glaucoma is a condition in which there is damage to the optic nerve, the nerve that carries visual signals from the eye to the brain. Damage is usually caused by a build-up of fluid (aqueous humour) within the eye, causing the pressure inside the eye to rise. Some people can get glaucoma with normal pressure as well. In the early stages of glaucoma someone may experience no symptoms. However, if it is left untreated, glaucoma can lead to severe loss of vision or even blindness. It is the leading cause of preventable irreversible blindness in the UK and the world.
When approximately 40-50% of the optic nerve is damaged, the peripheral (side) vision starts to be affected. If left untreated, this can then affect the central vision and lead to permanent and irreversible loss of vision. In most cases diagnosing the condition early and treating it effectively can avoid blindness.
What does being a glaucoma suspect patient mean?
You have been diagnosed as a ‘glaucoma suspect’ patient. Fortunately this means you do not have glaucoma, but you have some features that may indicate the condition.
This could mean that either:
the state of your optic nerve, which starts at the back of the eye, may indicate glaucoma
your visual fields (side vision) are abnormal
there is raised pressure in your eye (a risk factor for glaucoma)
you have a family history of glaucoma
OR You may have a combination of these factors.
Is my optic nerve normal or abnormal?
The optic nerve can vary a lot in appearance from one person to the next. This means it is sometimes difficult to know whether 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. However, if there is a change it may suggest a progressive (worsening) disease like glaucoma. Some ways that the optic nerve may suggest glaucoma
High myopic (short sighted) patients have longer eyeballs than others, and their optic nerves can look like they are damaged but the appearance can be normal for your eye.
Sometimes the optic nerve can enter the back of the eyeball at an angle rather than straight on. They therefore look tilted from the top. This can give the impression that the tilted side of the nerve head is thinner than the rest. (The optic nerve head is the beginning of the optic nerve that is visible at the back of the eye.) Even though this is unusual, this is normal for that eye.
Occasionally patients look like they have a bigger nerve head at the back of one eye compared with the other. This can give the impression that the larger nerve head has fewer nerve fibres than the smaller one, but again this is normal for each eye.
Some reasons why visual fields may be abnormal
The visual field test measures how much peripheral (side) vision each eye has. A visual field test takes some time to understand and do properly. There is usually a learning curve. This means visual field test performance can get better over time. There are other factors that can cause a defect in your visual field other than glaucoma, such as your eye prescription, tilted discs, the upper lid coming down during the test, or other eye / optic nerve conditions
What will happen next
We will monitor the appearance of your optic nerves regularly using:
• examination of your eyes with specialised instruments and lenses
• photographs or scans of the nerve at the back of your eyes to help detect any subtle changes
• eye pressure checks
• visual fields tests to ensure your peripheral vision is not reducing.
If there is a detectable change in the appearance of the optic nerve, we will discuss this with you and consider treatment or further observation.
If we do diagnose glaucoma, it can be treated by daily eye drops, laser treatment, surgery or a combination of different treatments to reduce the eye pressure.