What Is Glaucoma?
Glaucoma is a group of eye conditions that damage the optic nerve — the critical connection between your eye and brain. The damage is most commonly linked to elevated pressure inside the eye (called intraocular pressure, or IOP), though it can also occur in eyes with normal pressure. Left untreated, glaucoma leads to irreversible vision loss and, ultimately, blindness.
It is one of the leading causes of preventable blindness worldwide, making early detection and regular eye exams crucial.
Types of Glaucoma
There are several forms, but two are most common:
- Primary Open-Angle Glaucoma (POAG): The most prevalent type. Fluid drains too slowly from the eye, gradually raising pressure. It develops silently over years with no pain.
- Angle-Closure Glaucoma: The drainage angle between the iris and cornea narrows or closes suddenly. This can cause acute attacks with rapid pressure spikes — a medical emergency requiring immediate care.
- Normal-Tension Glaucoma: Optic nerve damage occurs despite normal intraocular pressure, likely due to reduced blood flow to the nerve.
- Secondary Glaucoma: Caused by another condition such as eye injury, inflammation, or prolonged steroid use.
Recognising the Symptoms
This is what makes glaucoma so dangerous — most people have no symptoms in the early stages. By the time vision loss is noticed, significant, permanent damage has already occurred. Symptoms that may eventually appear include:
- Gradual loss of peripheral (side) vision — often the first area affected
- Tunnel vision in advanced stages
- Blurred or hazy vision
- Seeing halos around lights
- Eye pain and redness (primarily in acute angle-closure attacks)
- Nausea or vomiting (during acute attacks)
Who Is at Higher Risk?
While anyone can develop glaucoma, certain factors increase your risk:
- Age over 60 (risk increases significantly after 40)
- Family history of glaucoma
- Elevated intraocular pressure
- Thin corneas
- Certain medical conditions (diabetes, high blood pressure, heart disease)
- Long-term use of corticosteroid medications
- Previous eye injury or surgery
How Glaucoma Is Diagnosed
A comprehensive eye exam is the only way to detect glaucoma before significant vision loss occurs. Your eye doctor may perform:
- Tonometry — measures intraocular pressure
- Ophthalmoscopy — examines the optic nerve for damage
- Perimetry (visual field test) — maps your field of vision to detect losses
- Optical Coherence Tomography (OCT) — provides detailed imaging of the optic nerve and retinal layers
- Pachymetry — measures corneal thickness
Treatment Options
While lost vision cannot be restored, treatment can slow or halt further damage:
| Treatment Type | How It Works |
|---|---|
| Eye drops | Reduce fluid production or improve drainage; typically the first line of treatment |
| Oral medications | Used when drops alone aren't sufficient |
| Laser therapy (SLT/ALT) | Improves drainage of fluid from the eye |
| Surgery (trabeculectomy) | Creates a new drainage channel to lower pressure |
| Minimally invasive glaucoma surgery (MIGS) | Newer procedures with faster recovery times |
The Importance of Regular Eye Exams
Because glaucoma has no early symptoms, regular comprehensive eye exams are your best protection. Adults over 40 should have an eye exam at least every two years; those with risk factors should be tested annually. Early diagnosis is the single most important factor in preserving your vision.