Glaucoma: The “Silent Thief of Sight” and Why Screening After 40 Matters

By the Royal Eye & Ear Hospital Ophthalmology Team · 6 min read

Imagine losing your sight so slowly that you don’t notice until it’s too late. That is exactly how glaucoma works, and it is why eye doctors call it the “silent thief of sight.”

Glaucoma is a group of eye diseases that damage the optic nerve, the cable that carries images from your eye to your brain. In most cases this damage is linked to raised pressure inside the eye. It usually begins by stealing your side (peripheral) vision. Because your brain fills in the gaps, many people only notice something is wrong once a large part of their vision is already gone.

The hard truth: vision lost to glaucoma cannot be restored. The good news: with early detection and treatment, most people with glaucoma keep useful sight for life.

Why glaucoma is a special concern in Kenya

Research consistently shows that glaucoma is a leading cause of blindness in people of African descent. Compared with other populations, Africans tend to develop glaucoma at a younger age, often with higher eye pressure, and the disease can progress faster.

On top of this, awareness is low. Many patients arrive at an eye clinic for the first time when one eye is already badly damaged, often because they assumed blurry or “narrowing” vision was just a normal part of getting older, or that new glasses would fix it.

Who is most at risk?

Anyone can develop glaucoma, but your risk is higher if you:

• Are over 40, since risk rises with every decade of life. For people of African descent, doctors often recommend starting checks from age 35.
• Have a family history. A parent, brother or sister with glaucoma makes you several times more likely to develop it.
• Have diabetes or high blood pressure, which can affect blood flow to the optic nerve.
• Are very short-sighted or long-sighted, as the shape of the eye can raise the risk of certain types.
• Use steroid medicines long-term, including steroid eye drops, creams, inhalers or tablets, especially without medical supervision.
• Have had an eye injury or eye surgery in the past.

Symptoms: what to look out for

Open-angle glaucoma (the most common type)

This type develops slowly over years. In the early stages there are no symptoms at all: no pain, no redness, and your central vision stays sharp. As it advances you may notice:

• Patchy blind spots in your side vision
• Bumping into objects or door frames more often
• Difficulty seeing steps, kerbs or people approaching from the side
• In late stages, “tunnel vision”, as if looking through a tube

How is glaucoma detected?

A glaucoma check is quick, painless and done as part of a comprehensive eye examination. At Royal Eye & Ear Hospital, your assessment may include:

Eye pressure alone is not enough to diagnose glaucoma, as some people have glaucoma with “normal” pressure. That is why a full examination by an eye specialist matters.

Treatment: protecting the sight you have

The goal of treatment is to lower eye pressure and prevent further damage to the optic nerve. Options include:

• Eye drops. The most common first treatment. They must be used every day, exactly as prescribed, even when your eyes feel fine.
• Laser treatment. A quick outpatient procedure that helps fluid drain from the eye and can reduce or replace the need for drops.
• Glaucoma surgery. Creates a new drainage pathway when drops and laser are not enough.

Glaucoma is a lifelong condition. Regular follow-up visits allow your doctor to confirm the treatment is working and adjust it if needed.

Myths vs facts

How often should you get checked?

As a general guide:

• Under 40, no risk factors: a full eye exam every few years, or sooner if you notice changes.
• Over 40: a full eye exam every 1–2 years.
• Family history, diabetes or other risk factors: start earlier and follow your eye doctor’s advice, often once a year.

If someone in your family has been diagnosed with glaucoma, encourage your brothers, sisters and children to get checked too. One appointment could protect a whole family’s sight.

Frequently asked questions

This article is for general information only and does not replace a consultation with a qualified eye specialist. If you have concerns about your vision, please book an appointment or visit your nearest eye clinic.