What is Glaucoma?
Glaucoma is a group of eye conditions characterised by progressive damage to the optic nerve — the bundle of nerve fibres that transmits visual information from the eye to the brain. In most cases, this damage is caused by elevated intraocular pressure (IOP), though glaucoma can also occur with normal pressure (a condition called normal tension glaucoma).
Glaucoma is one of the leading causes of irreversible blindness worldwide. In Australia alone, it affects approximately 300,000 people — with many more undiagnosed. Unlike most causes of vision loss, glaucoma damage cannot be reversed. However, with early detection and treatment, vision loss can almost always be prevented or significantly slowed.
Why is it Called the Silent Thief of Sight?
Glaucoma earns its name because it typically causes no pain and no obvious symptoms in its early and intermediate stages. The vision loss it causes begins at the periphery (edges of the visual field) and progresses inward — so slowly and so subtly that most people do not notice it until significant, irreversible damage has already occurred. By the time central vision is affected, the disease is already advanced.
This is why glaucoma is so dangerous, and why regular eye examinations — even in the absence of symptoms — are the only reliable way to detect it early.
Types of Glaucoma
Primary open-angle glaucoma (POAG) is the most common form. In POAG, the drainage angle of the eye is structurally open but functions poorly, causing IOP to rise gradually. There are no symptoms in the early stages.
Normal tension glaucoma (NTG) is a form in which optic nerve damage occurs despite IOP being within the statistically normal range. Vascular factors and optic nerve susceptibility play important roles.
Angle-closure glaucoma occurs when the drainage angle is physically blocked by the iris. It can present as a sudden, painful attack (acute angle closure) — a medical emergency — or develop slowly without symptoms. Laser peripheral iridotomy is often curative for the angle-closure component.
Secondary glaucomas arise from other eye conditions, including trauma, uveitis (eye inflammation), steroid use, or pseudoexfoliation syndrome.
Risk Factors
Anyone can develop glaucoma, but certain factors significantly increase your risk:
Family history: First-degree relatives of a person with glaucoma have a four to nine times higher risk. If a parent or sibling has glaucoma, regular screening is strongly recommended.
Age: The risk of glaucoma increases significantly after age 60.
Elevated intraocular pressure (ocular hypertension): Even without glaucoma, elevated IOP increases the risk of developing the condition.
Myopia (short-sightedness): Moderate to high myopia is an independent risk factor for open-angle glaucoma.
Ethnicity: People of African or Caribbean heritage are at significantly higher risk and tend to develop glaucoma at a younger age. People of East Asian heritage have a higher risk of angle-closure glaucoma.
Corneal thickness: A thin central cornea is associated with higher risk of glaucoma progression.
Symptoms of Acute Angle Closure — Seek Urgent Care
While most glaucoma is silent, acute angle-closure glaucoma is a notable exception. It presents as a sudden, severe eye ache or headache, blurred vision, halos around lights, nausea and vomiting, and a red eye. It is a medical emergency. If you or someone you know experiences these symptoms, seek urgent ophthalmological care immediately. Acute angle closure can cause permanent vision loss within hours if untreated.
How Glaucoma is Diagnosed
Glaucoma diagnosis requires a series of investigations, as no single test is conclusive on its own. At Northern Eye Consultants, assessment typically includes intraocular pressure measurement (tonometry), visual field testing (perimetry) to map areas of vision loss, OCT imaging of the optic nerve fibre layer to detect structural damage, optic disc photography and assessment, gonioscopy (examination of the drainage angle), and corneal thickness measurement (pachymetry).
Treatment Options
The goal of glaucoma treatment is to lower intraocular pressure and thereby slow or stop optic nerve damage. Treatment options include:
Eye drops: Pressure-lowering drops are the most common first-line treatment. Various classes are available and are tailored to each patient.
Selective Laser Trabeculoplasty (SLT): A safe, effective office-based laser treatment that improves aqueous drainage from the eye. Can be used as first-line therapy or as an adjunct to drops.
Minimally Invasive Glaucoma Surgery (MIGS): Microscopic devices and techniques to lower IOP with a lower risk profile than traditional surgery, often performed at the time of cataract surgery.
Trabeculectomy and glaucoma drainage devices (tube surgery): More complex surgical procedures for advanced or refractory glaucoma, performed by our specialist glaucoma surgeons.
The Bottom Line
Glaucoma cannot be reversed, but it can be managed effectively when detected early. If you are aged over 50, have a family history of glaucoma, are highly myopic, or belong to a higher-risk ethnic group, regular eye examinations are essential — even if your vision seems perfectly fine. The best way to prevent vision loss from glaucoma is to find it before it causes damage.