Glaucoma

Glaucoma is often called the ‘silent thief of sight’ because the most common forms cause no symptoms until significant vision has already been lost. This is why regular eye examinations are so important, particularly as you get older and if you have risk factors for the disease.

At Pure Sight Eye Surgeons, we provide comprehensive glaucoma screening, monitoring, and treatment. Our team uses advanced imaging, including optical coherence tomography and visual field testing, to detect glaucoma at its earliest stages and track any changes over time.

How Glaucoma Develops

Inside the eye, a clear fluid called aqueous humour is constantly produced by the ciliary body structure behind the iris, the coloured part of the eye. This fluid drains out through a mesh-like structure called the trabecular meshwork, located in the angle where the iris meets the cornea. This continuous production and drainage maintains a stable pressure inside the eye, known as intraocular pressure (IOP).

In glaucoma, the drainage system doesn’t work as efficiently as it should, or there is an imbalance between fluid production and drainage. This can cause the intraocular pressure to rise, which over time damages the sensitive nerve fibres of the optic nerve. Once these fibres are damaged, the vision loss they cause is permanent.

Types of Glaucoma

Primary open-angle glaucoma

This is the most common form of glaucoma in Australia. The drainage angle between the iris and cornea remains physically open, but the trabecular meshwork gradually becomes less efficient at draining fluid. Pressure rises slowly, and there are typically no symptoms until the disease is well advanced. Peripheral vision is usually affected first, while central vision is preserved until late stages.

Normal-tension glaucoma

In this form, the optic nerve is damaged despite the intraocular pressure being within the statistically normal range. It may be that the optic nerve is unusually sensitive to pressure, or that reduced blood flow to the nerve plays a role. Diagnosis requires careful assessment of the optic nerve and visual fields.

Angle-closure glaucoma

This occurs when the iris is pushed or pulled forward, physically blocking the drainage angle. It can happen suddenly (acute angle closure) causing severe eye pain, headache, nausea, blurred vision, and halos around lights. This is an eye emergency that requires immediate treatment to prevent permanent vision loss. Angle-closure glaucoma is more common in people who are long-sighted, have smaller eyes, or are of East Asian descent.

Secondary glaucoma

Glaucoma can develop as a complication of other conditions or factors, including:

• Neovascular glaucoma — abnormal blood vessel growth blocks the drainage angle, often secondary to diabetic eye disease or retinal vein occlusion
• Uveitic glaucoma — inflammation inside the eye damages the drainage system
• Pseudoexfoliative glaucoma — flaky material from the lens accumulates in the drainage angle
• Steroid-induced glaucoma — prolonged use of corticosteroid medications, including eye drops and inhalers
• Traumatic glaucoma — following eye injury

Congenital glaucoma

This rare form is present from birth, caused by abnormal development of the eye’s drainage system. It often runs in families and is typically diagnosed and managed by paediatric ophthalmologists.

Symptoms

Most types of glaucoma cause no symptoms in the early stages. Open-angle glaucoma and normal-tension glaucoma can progress silently for years, gradually reducing peripheral vision before affecting central vision. Many people don’t realise they have the condition until significant damage has occurred.

Acute angle-closure glaucoma is the exception. It presents suddenly with:

• Severe eye pain
• Headache (often on the same side)
• Nausea and vomiting
• Sudden blurred vision
• Halos around lights
• A red eye

If you experience these symptoms, seek emergency medical attention immediately. Acute angle-closure glaucoma can cause permanent vision loss within hours if not treated.

Diagnosis

Glaucoma diagnosis involves several complementary tests:

• Tonometry — measures the intraocular pressure
• Gonioscopy — uses a special lens to examine the drainage angle and determine whether it’s open or narrow
• Optic nerve assessment — the optic nerve head is examined for signs of damage, including cupping (enlargement of the central depression)
• Optical coherence tomography (OCT) — provides detailed measurements of the optic nerve fibre layer and can detect thinning before it becomes visible on examination
• Visual field testing — maps the full extent of your side vision to identify any areas of loss. This is a key test for both diagnosis and monitoring
• Pachymetry — measures central corneal thickness, which influences the accuracy of pressure readings

Because glaucoma is a progressive condition, regular follow-up examinations are essential. Comparing results over time allows your doctor to detect any worsening and adjust treatment accordingly.

Treatment

The goal of glaucoma treatment is to lower the intraocular pressure to a level that prevents further optic nerve damage. Existing damage can’t be reversed, which is why early detection and treatment are so important.

Eye drops

Medicated eye drops that reduce eye pressure are the most common first-line treatment. Several types are available, and your doctor will prescribe the most appropriate option for your type of glaucoma. Drops need to be used consistently, typically once or twice daily, to be effective.

Selective laser trabeculoplasty (SLT)

SLT is a laser treatment that stimulates the trabecular meshwork to improve its drainage function. It’s increasingly used as a first-line treatment for open-angle glaucoma, either instead of or alongside eye drops. The procedure is performed in the clinic by our surgeons, takes only a few minutes, and can be repeated if needed.

Laser iridotomy

For angle-closure glaucoma or narrow angles, a laser creates a small opening in the iris to improve the flow of fluid from behind the iris to the drainage angle. This is performed in our clinic rooms by all surgeons at Pure Sight. It’s a preventive treatment that reduces the risk of an acute angle-closure attack.

Minimally invasive glaucoma surgery (MIGS)

MIGS procedures involve inserting microscopic drainage devices to improve fluid outflow from the eye. These are often performed at the same time as cataract surgery, providing the opportunity to address both conditions in a single procedure. MIGS carries less risk than traditional glaucoma surgery and has a shorter recovery time.

Traditional glaucoma surgery

In cases where drops, laser, and MIGS are insufficient, more extensive surgical options such as trabeculectomy or tube shunt surgery may be considered. These procedures are typically managed by a glaucoma subspecialist.

Frequently Asked Questions