Glaucoma

Glaucoma is one of Australia’s leading causes of permanent blindness, yet up to 50% of people who have it don’t know it.¹ Glaucoma causes gradual, painless damage to the optic nerve that acts as the vital connection between the eye and the brain. By the time most people notice their vision changing, irreversible damage has already occurred.

When detected early, treatment of glaucoma can preserve a person’s remaining vision. This makes regular eye examinations one of the most important things Australians can do for their long-term sight.

In most cases of glaucoma, fluid that normally circulates inside the eye cannot drain properly. This causes intraocular pressure to build up, gradually damaging the optic nerve. However, glaucoma can also occur in people with normal or even low eye pressure, which is why pressure alone is not the whole story.

There are two main types of glaucoma:

Primary open-angle glaucoma is the most common form. The eye’s drainage channels gradually become less efficient over time, raising intraocular pressure slowly and without any noticeable symptoms until significant vision loss has occurred.

Acute angle-closure glaucoma is a less common but more acute form, where the drainage angle between the iris and cornea becomes suddenly blocked, causing a rapid, dangerous spike in eye pressure. Acute angle-closure glaucoma is a medical emergency. Symptoms include sudden severe eye pain, nausea, blurred vision and seeing halos around lights.

Risk factors for developing glaucoma include increasing age, a family history of the condition, elevated intraocular pressure, high myopia, and diabetes.

In most cases of glaucoma, there are no noticeable symptoms in the early stages. The clinical features of glaucoma typically only become apparent once meaningful vision loss has already occurred. When symptoms do appear, they may include:

Gradual loss of peripheral (side) vision – typically the first sign of open-angle glaucoma, though it is often so gradual that it goes unnoticed until peripheral vision is significantly reduced.

Tunnel vision – in advanced glaucoma, peripheral vision loss creates a narrowing visual field where a person may only be able to see what is directly in front of them.

Blurred vision – central vision may become blurred or reduced as the optic nerve deteriorates, particularly in more advanced stages.

Sudden severe eye pain (acute angle-closure glaucoma) – a sudden, intense ache or pressure in and around the eye is a hallmark symptom of acute angle-closure glaucoma and requires immediate emergency medical attention.

Nausea and vomiting (acute angle-closure glaucoma) – the rapid rise in intraocular pressure during an acute glaucoma episode can cause nausea, vomiting and general unwellness, sometimes leading people to mistake the episode for a migraine.

Seeing halos around lights – halos or rainbow-coloured rings around lights, particularly at night, can occur in both acute angle-closure and open-angle glaucoma.

Redness of the eye – eye redness can occur during an acute glaucoma attack and may be accompanied by a dilated pupil that does not respond normally to light.

The only reliable way to detect glaucoma early is through a comprehensive eye examination, including measurement of intraocular pressure and assessment of the optic nerve.

Everyday activities that may become difficult as glaucoma progresses include:

• Driving, particularly noticing pedestrians or hazards at the edges of the road
• Navigating stairs, kerbs or uneven surfaces safely
• Reading or working at a screen, particularly if central vision is also affected in later stages
• Bumping into people or objects on your side or just ahead of you
• Misjudging distances or the position of objects
• Feeling less safe or confident in busy or unfamiliar environments
• Increased difficulty in low-light conditions, as peripheral vision contributes significantly to night vision

If you notice any of these signs, speak to your GP.

Glaucoma treatment focuses on lowering intraocular pressure to slow or halt further optic nerve damage. The goal is to preserve remaining vision for life.

Glaucoma laser surgery is increasingly used as a first-line treatment in Australia, as an alternative or complement to eye drops.

For those living with vision loss from glaucoma, Guide Dogs Australia is here to help at every stage of that journey.

• Orientation and mobility training – building confidence and practical skills to move safely and independently as peripheral vision narrows.
• Assistive technology support – screen magnification, high contrast displays and low vision aids to support independence in daily life.
• Early childhood services – for those adjusting to vision changes caused by glaucoma at any stage of life.
• Psychology and counselling – for people navigating the emotional impact of a chronic, progressive vision condition.
• Peer support – connecting with others who understand the experience of living with vision impairment firsthand.

Beyond Guide Dogs Australia, Glaucoma Australia provides free education and support services specifically for people living with glaucoma, including access to glaucoma educators, resources in multiple languages, and an online support community.

Because glaucoma is hereditary in many cases, family members of someone diagnosed should be told and encouraged to have a glaucoma test. Whatever the type or stage, early detection is the single most important factor in preserving vision from glaucoma.

¹ Glaucoma Australia, Glaucoma Information and Referral, Glaucoma Australia Inc., 2019. Available at: https://glaucoma.org.au/sites/default/files/2020-08/GA_11299_2019_Information-Referral_16pp_DL_FA-ONLINE.pdf