Glaucoma Explained: What It Is, Why It Matters, and How It Is Detected

Glaucoma is one of the leading causes of preventable sight loss worldwide, yet many people know very little about it until they or a loved one are diagnosed. Often referred to as the "silent thief of sight," glaucoma can develop slowly over many years without causing any pain or noticeable symptoms.

Understanding the basics of glaucoma is one of the most important steps you can take to protect your vision.

What is glaucoma?

Glaucoma is a group of eye conditions that damage the optic nerve, the structure responsible for carrying visual information from the eye to the brain. Once optic nerve fibres are damaged, they cannot regenerate, making any vision loss permanent.

In many cases, glaucoma is associated with increased pressure inside the eye, known as intraocular pressure. However, glaucoma can also occur in people with normal eye pressure, which is why pressure testing alone is not enough to diagnose the condition.

Why is glaucoma called the "silent thief of sight"?

The most common form of glaucoma, primary open-angle glaucoma, develops very gradually. It typically affects peripheral (side) vision first, leaving central vision untouched in the early stages.

Because the changes occur so slowly, the brain adapts remarkably well. Many people remain completely unaware that their field of vision is narrowing. By the time symptoms become noticeable, significant and irreversible damage may already have occurred.

This is why glaucoma is often discovered during a routine eye examination rather than because a patient notices a problem.

Who is at risk?

Anyone can develop glaucoma, but certain factors increase the likelihood:

• Being over the age of 40
• Having a parent or sibling with glaucoma
• Being of African, Caribbean, or Asian heritage
• Having diabetes
• Having high levels of short-sightedness
• Using steroid medication for extended periods
• Having elevated eye pressure

If you fall into one or more of these groups, regular eye examinations become even more important.

How is glaucoma detected?

Diagnosing glaucoma involves looking at several aspects of eye health rather than relying on a single test.

During an eye examination, your optometrist may:

• Measure the pressure inside your eyes
• Examine the appearance of your optic nerve
• Assess your peripheral vision
• Review photographs and scans of the retina and optic nerve

Modern technology has significantly improved our ability to detect glaucoma early. Optical Coherence Tomography (OCT) scans use light waves to create highly detailed cross-sectional images of the retina and optic nerve. These scans can identify microscopic changes in nerve fibre thickness long before vision is affected.

Early detection allows treatment to begin before substantial sight loss occurs.

Can glaucoma be treated?

While vision already lost to glaucoma cannot be restored, treatment can usually slow or stop further damage.

The most common treatment is prescription eye drops designed to reduce pressure within the eye. In some cases, laser procedures or surgery may be recommended.

The goal of treatment is simple: preserve the vision you still have.

The importance of regular eye examinations

One of the biggest misconceptions about glaucoma is that you will know if you have it. Unfortunately, this is often not the case.

Because glaucoma frequently develops without pain or obvious symptoms, routine eye examinations remain the most effective way to detect it early. Regular appointments allow your optometrist to monitor changes over time