Glaucoma: Symptoms, Causes and Treatments

Glaucoma is a group of eye conditions that damage the optic nerve, the nerve that carries visual information from your eye to your brain. It usually develops slowly and without pain, so most people have no idea anything is wrong until vision has already been lost. It is estimated that more than 300,000 Australians have glaucoma, and about half of them don’t yet know it.

Because that damage cannot be reversed, everything depends on finding it early, and early glaucoma is found in a routine eye test rather than nt home. Here’s how to identify the symptoms.

Disclaimer: This article is general information only and is not a substitute for professional medical advice. If you notice any change in your vision, book an appointment with your optometrist or ophthalmologist.

Key Takeaways

• Glaucoma damages the optic nerve and causes permanent vision loss if left untreated.
• More than 300,000 Australians have glaucoma, and around half are undiagnosed.
• Open-angle glaucoma, the most common type, usually has no early symptoms at all.
• Acute angle-closure glaucoma is a medical emergency needing immediate hospital care.
• A direct family member with glaucoma makes you roughly ten times more likely to develop it.
• Treatment lowers eye pressure to protect remaining sight, but cannot restore vision already lost.

What is Glaucoma?

Glaucoma is an eye condition that affects the optic nerve at the back of the eye. The optic nerve is essential to sight, because it transmits information from your eyes to your brain. In glaucoma, the optic nerve deteriorates progressively over time, causing permanent vision loss, and in advanced stages this can narrow to tunnel vision.

Glaucoma is closely related to intraocular pressure, which is the pressure inside the eye. High intraocular pressure can lead to glaucoma, although eyes with normal or even low pressure can develop it too.

Glaucoma is often called the silent thief of sight, because the damage builds without pain or obvious warning. It’s also the leading cause of irreversible blindness worldwide, and this is where it differs from a condition like cataracts, where clouded vision can usually be restored with surgery. With glaucoma, sight that has gone doesn’t return.

Glaucoma is one of several eye conditions that are far easier to manage when caught early. The same is true of macular degeneration and diabetic retinopathy.

What are the types of glaucoma?

There are several types of glaucoma, and they behave very differently. The two main forms are open-angle and angle-closure glaucoma. Primary open-angle glaucoma is the most common form in Australia.

Open-angle glaucoma

The eye’s drainage system gradually becomes less effective, causing pressure to build up over time. It usually develops without symptoms at first and can lead to peripheral vision loss. Regular eye tests help detect and monitor it.

Angle-closure glaucoma

The eye’s drainage angle becomes blocked, causing pressure to rise quickly. Symptoms may include severe eye pain, redness, blurred vision, halos around lights, nausea or vomiting.

Sudden angle-closure glaucoma is a medical emergency. Seek immediate medical attention.

When glaucoma is an emergency?

Most glaucoma develops slowly and is picked up in a routine eye test, with no drama attached. One type behaves differently, and it’s worth knowing what to look for. Acute angle-closure glaucoma can damage sight within hours. If you have sudden eye pain and redness, blurred or worsening vision, or you see halos around lights, go to your nearest emergency department or call triple zero (000) and ask for an ambulance.

Don’t wait for an optometry appointment. Sudden pain in or behind the eye always warrants same-day attention.

 

What are the symptoms of glaucoma?

Glaucoma symptoms depend on the type. In the early stages of open-angle glaucoma, there are usually no symptoms at all, and as the condition progresses, loss of peripheral vision becomes noticeable. This is why regular eye check-ups matter so much for detecting glaucoma early and treating it quickly.

The reason early glaucoma goes unnoticed is that your vision is better at hiding it than you might expect. Peripheral loss starts at the very edges, your brain fills in the missing areas, and your other eye covers the gaps, so nothing looks obviously wrong. By the time a patient notices vision loss, irreversible damage has already occurred. 

As it advances, you may notice:

• Patchy blind spots towards the edges of your vision, often in both eyes
• Difficulty seeing in dim light, or slower adjustment when moving between bright and dark rooms
• Bumping into door frames, missing kerbs, or not seeing objects off to the side
• Tunnel vision in the advanced stages, where only what is directly ahead remains clear

Angle-closure glaucoma is different, and its symptoms are hard to ignore. Severe eye pain, a red eye, sudden blurring, halos around lights, and nausea or vomiting all point to a possible acute attack, which needs emergency care rather than a routine appointment.

What causes glaucoma?

The exact cause of glaucoma is still unknown, but it is strongly related to eye pressure and a number of other factors.

Eye pressure depends on the amount of fluid inside the eye. This fluid, called aqueous humour, normally circulates through the eye like a pump system. When there is an overproduction of aqueous humour or a blockage in the drainage channels, fluid builds up and eye pressure rises. That increase in pressure can damage the optic nerve, leading to progressive vision loss.

Importantly, pressure is only part of the picture. Some people develop glaucoma at pressures considered normal, which is called normal-tension glaucoma, and others live with raised pressure for years without nerve damage. This is why an optometrist assesses the health of the optic nerve itself, not just the pressure reading.

Who is most at risk of glaucoma?

People in older age groups are far more susceptible. Those aged 80 or over are 17 times more likely to have glaucoma than people under 50. That said, glaucoma is still found in people under 50.

Putting numbers to that, Glaucoma Australia reports that around 1 in 200 people have glaucoma by age 40, rising to roughly 1 in 8 by age 80. Other factors that increase risk include:

• Family history, if a parent, sibling or extended relative has glaucoma
• Diabetes
• Being short-sighted, or myopia
• Smoking
• Long-term use of steroid medication, including steroid eye drops
• A previous eye injury, eye surgery, or a history of raised eye pressure
• Being of African, Asian or Hispanic descent, which carries a higher baseline risk for certain types
  

How is glaucoma diagnosed?

Glaucoma is diagnosed through a comprehensive eye examination, not a single test. Optometrists have various methods of assessing eye pressure, the peripheral fields of view, corneal thickness, and the health of the nerve structures at the back of the eye.

• Tonometry, which measures the pressure inside your eye, sometimes using a brief puff of air
• Visual field testing, which maps the edges of your vision to find gaps you would not notice yourself
• An OCT scan, which images the optic nerve in cross-section and can detect thinning of the nerve fibres before any vision is lost
• A retinal photograph, which gives your optometrist a permanent record of the optic nerve so changes can be compared year on year
• Corneal thickness measurement, because a thin cornea can make pressure readings appear lower than they really are

Most of these are part of a standard eye test, and eligible patients can access a bulk-billed eye test through Medicare, so cost need not be a barrier to being checked.

How is glaucoma treated?

Early diagnosis is paramount. Some optometrists treat glaucoma themselves and others refer to an ophthalmologist, and in both cases careful follow-up is essential.

Glaucoma is treated by lowering eye pressure. Your practitioner may prescribe eye drops, or recommend laser or implant surgery. Surgery is generally reserved for severe glaucoma, or for cases where eye drops have not worked.

What treatment cannot do is undo damage that has already happened. Lowering pressure protects the nerve fibres you still have, which is why glaucoma is usually managed for life rather than cured, and why sticking to the treatment plan matters as much as the plan itself.

Next steps 

Glaucoma is manageable when it is found early, and unforgiving when it’s not. Book a comprehensive eye test if you’re over 40 and haven’t had one in the last two years.

Find your nearest clinic and book an appointment with one of our optometrists.