Glaucoma: The Silent Thief of Sight — Symptoms & Tests

What Is Glaucoma?

Glaucoma is not a single disease but a group of progressive optic neuropathies — conditions that damage the optic nerve, which carries visual information from the eye to the brain. The most common form, primary open-angle glaucoma, is typically associated with elevated intraocular pressure (IOP), though normal-tension glaucoma — where optic nerve damage occurs despite normal pressure — is also well recognised. Regardless of the mechanism, the end result is the same: irreversible loss of retinal ganglion cells and their axons, causing permanent visual field loss.

Why Is Glaucoma Called the Silent Thief of Sight?

In primary open-angle glaucoma — which accounts for the vast majority of cases — there are absolutely no symptoms in the early stages. The patient feels no pain. Vision appears normal in day-to-day activities. This is because glaucoma first destroys peripheral (side) vision, and the brain is remarkably good at filling in the gaps. By the time a patient notices something wrong — typically a tunnel-like narrowing of their visual field — they have already lost 40–50% of their optic nerve fibres. This damage is permanent and cannot be reversed. This is why glaucoma is called the silent thief of sight.

Who Is Most at Risk of Glaucoma?

While glaucoma can affect anyone, certain factors significantly increase your risk:

Age: The risk doubles for every decade after 40. Anyone over 60 should have annual glaucoma screening.

Family history: First-degree relatives of glaucoma patients have a 4–9 times higher risk. If a parent or sibling has glaucoma, regular screening is essential.

Elevated intraocular pressure: IOP above 21 mmHg is a significant risk factor, though not everyone with high IOP develops glaucoma.

Thin central corneal thickness: A thin cornea predicts higher glaucoma risk and also leads to underestimation of true IOP with standard tonometry.

High myopia: Highly myopic eyes have a structurally vulnerable optic nerve head.

Diabetes and hypertension: Both increase the risk of optic nerve damage.

Long-term steroid use: Topical, oral, or inhaled corticosteroids can raise IOP in susceptible individuals.

How Is Glaucoma Diagnosed?

Early detection of glaucoma requires sophisticated imaging and functional testing. At FIO Hospital, we use gold-standard diagnostic equipment:

ZEISS CIRRUS HD-OCT 6000: The most advanced optical coherence tomography system available, capable of imaging the optic nerve head and retinal nerve fibre layer at ultra-high resolution. This allows us to detect structural glaucoma damage years before any visual field loss occurs.

Humphrey Field Analyzer 3 (HFA3): The global gold standard for visual field testing, measuring the sensitivity of your peripheral vision at hundreds of test points. Early glaucomatous field defects have a characteristic pattern that allows confident diagnosis.

Goldmann applanation tonometry: The reference standard for intraocular pressure measurement.

Gonioscopy: Examination of the drainage angle to classify the type of glaucoma and guide treatment decisions.

How Is Glaucoma Treated?

There is currently no cure for glaucoma — vision already lost cannot be recovered. However, with early detection and consistent treatment, the vast majority of patients retain useful vision for life. Treatment aims to lower IOP to a "target pressure" that stops further optic nerve damage.

Eye drops: The mainstay of treatment. Prostaglandin analogues (once daily at night), beta-blockers, alpha-agonists, and carbonic anhydrase inhibitors all reduce IOP through different mechanisms. Adherence is critical — missing doses allows pressure spikes that accelerate damage.

Selective Laser Trabeculoplasty (SLT): A quick, painless in-office laser procedure that improves drainage through the trabecular meshwork. It is increasingly used as a first-line treatment, reducing or eliminating the need for daily eye drops. Effects typically last 3–5 years and the procedure can be repeated.

Minimally Invasive Glaucoma Surgery (MIGS): A newer category of surgical procedures that lower IOP with a much better safety profile than traditional glaucoma surgery. MIGS procedures can often be performed at the same time as cataract surgery.

Traditional glaucoma surgery: For advanced or uncontrolled glaucoma, trabeculectomy or tube shunt surgery creates a new drainage pathway for aqueous humour, achieving the greatest IOP reduction.

Why Is Regular Glaucoma Screening So Important?

Given that glaucoma has no symptoms until significant damage has occurred, the only way to protect your vision is through regular eye examinations. We recommend annual screening for all adults over 40, and every 6 months for those with risk factors. A comprehensive glaucoma evaluation at FIO Hospital takes approximately one hour and includes all of the diagnostic tests described above.

Call us at +92 91-5812-391 to schedule your glaucoma screening today. Your vision tomorrow depends on the actions you take today.

Learn more about glaucoma treatment at FIO Hospital, read our guide to glaucoma as a condition, or book a pressure and optic nerve check.