Half the people in the UK with glaucoma have no idea they have it. That is not a typo. Of the roughly 700,000 people living with the condition, around 350,000 are walking around with sight quietly being taken from them, one tiny fragment at a time, and they cannot feel a thing.
That is what makes glaucoma so unsettling. There is no headache, no blurred vision, no warning shot. Most people only discover the damage when a routine eye test reveals it, and by then, some of that lost sight is gone for good. The good news is that early detection changes the story completely. Caught in time, glaucoma can almost always be managed well enough to keep useful vision for the rest of your life.
In this guide, you will learn how glaucoma actually works, why it earned its “silent thief” nickname, who is most at risk, and what a thorough glaucoma test should look like in 2026. If you are over 40, have a family history, or have simply never given your eye pressure a second thought, this is worth ten minutes of your time. Book an appointment if you are due a check-up, or read on first and decide for yourself.
What Glaucoma Actually Is, and Why It Sneaks Up
Glaucoma is not one single condition. It is a family of eye diseases that share a common ending: damage to the optic nerve, the cable that carries everything your eye sees to your brain. When that nerve frays, the signal weakens, and your field of vision shrinks. Once a fibre dies, it cannot be brought back, which is why prevention does the heavy lifting here.
In the most common form, called open-angle glaucoma, the fluid inside your eye drains a little too slowly. Pressure builds up gradually, year after year, and slowly damages the optic nerve at its weakest points. The damage starts at the edges of your vision, which is exactly the part of your sight you tend not to notice. Your brain is clever, and it fills in the gaps using information from your other eye, so you do not realise anything is wrong until the loss reaches your central vision. By that stage, you might have lost up to 40 per cent of your vision without ever noticing.
Closed-angle glaucoma is the rarer, more dramatic cousin. The drainage channel inside the eye blocks suddenly, pressure rockets up, and the symptoms are unmissable: severe eye pain, blurred vision, halos around lights, nausea, and a red, hard eye. This is a genuine emergency. If that ever describes you, go to A&E, not your optician.
There are other variants too: normal-tension glaucoma, where the optic nerve is damaged despite eye pressure readings in the normal range, and secondary glaucomas triggered by injury, certain medications, or underlying conditions. All of them, though, come back to the same thing. Damage to the optic nerve that you cannot feel until it is too far along.
Who Should Pay Closer Attention
Anyone can develop glaucoma, but some people sit in a higher-risk lane and should be tested more often. Age is the biggest factor: the condition affects roughly two in every 100 people over 40 and rises to about one in 20 by the age of 80. Family history is the next big one. If a parent or sibling has glaucoma, your risk is at least four times higher than someone without that history. That figure climbs even higher for siblings of people with the condition.
Ethnicity matters too. People of African or Caribbean heritage have around a four-times higher risk of open-angle glaucoma and tend to develop it earlier in life. People of East Asian heritage have an elevated risk of the closed-angle form. Other risk factors include short-sightedness, long-sightedness, diabetes, very high or very low blood pressure, long-term use of steroid medication, and a history of eye trauma or surgery.
Here is the part that matters practically. If you are 40 or over and have a close relative with glaucoma, the NHS funds a free eye test for you in England, regardless of your other circumstances. It is one of the most underused entitlements in British eye care, and we still meet patients in Harborne who have no idea it applies to them. If that sounds like you, please come and use it. We will check whether you qualify when you arrive.
What “Silent” Really Means in Day-to-Day Life
Picture someone in their early fifties, no complaints about their sight, driving themselves to a routine eye test, reading comfortably in the waiting area. A visual field test then reveals they have already lost a significant chunk of peripheral vision in one eye. This is not a rare scenario. People in the early and middle stages of glaucoma simply cannot feel it happening. They compensate without realising: turning the head a little more in conversation, missing the occasional cup at the back of a cupboard, putting it all down to age or distraction.
This is why “wait until I notice something” is the riskiest approach to eye health you can take. The whole point of a proper glaucoma test is to catch the damage your nervous system is too kind to tell you about.
What an Actual Glaucoma Test Looks Like
The phrase “glaucoma test” gets used a lot, but it is really shorthand for a small battery of checks that, taken together, build a picture of your optic nerve and how it is coping. At Brittain Opticians, our standard 40-minute eye examination includes several of these as a matter of course, with more available where the picture suggests further investigation.
The first is the eye pressure test, called tonometry. The old-fashioned version uses a puff of air, which most people remember with a wince. We use a no-puff tonometer in our Harborne practice, which is far gentler and gives a more accurate reading. It measures the pressure inside your eye, called intraocular pressure or IOP. Anything consistently over 21 mmHg deserves closer attention, although it is worth noting that around 40 per cent of people with glaucoma have pressure within the “normal” range. Pressure alone is never the whole story.
The second is digital retinal imaging. We take a high-resolution photograph of the back of your eye, including the optic nerve head. This is where the damage from glaucoma shows up first, typically as “cupping” of the optic disc, where the central depression deepens as nerve fibres are lost. The brilliant thing about retinal imaging is that we can compare your image year on year and spot subtle changes you would never catch with a one-off look. You can read more about how we use retinal imagery in our day-to-day care.
Where the picture from your retinal image or pressure reading suggests further investigation, your optometrist may recommend an OCT scan. OCT uses light waves to take a cross-sectional image of the retina, measuring the thickness of the nerve fibre layer with extraordinary precision. It can detect changes years before they would show up on a basic eye test, which is exactly the kind of head start you want with a disease this quiet. If we feel an OCT would help build a clearer picture, we will talk you through your options.
A visual field test maps your peripheral vision by flashing small lights at various points and asking you to indicate what you see. Early glaucoma typically shows up here as small gaps or dim spots at the edges, long before you would consciously notice them. It takes about ten minutes per eye and is genuinely fascinating to watch your own results.
How Often You Should Be Tested
For most adults, the NHS recommends a sight test every two years. If you are over 40 with a family history of glaucoma, or in another higher-risk group, we will usually recommend yearly tests. After a glaucoma diagnosis, monitoring becomes more frequent, often every four to six months, while we establish a baseline. Your optometrist will tell you what makes sense for your circumstances. There are no universal rules here, only sensible ones tailored to you.
What Happens If We Find Something
This is the question patients quietly worry about, so let us answer it straight. If your test results suggest you have glaucoma or are at high risk of developing it, we refer you to the hospital eye service for confirmation and treatment planning. The team there will repeat some of the tests, often with more specialist equipment, and discuss your options.
Treatment for most types of glaucoma starts with eye drops. They reduce the pressure inside the eye, either by helping fluid drain or by slowing its production, and they are typically used once or twice a day for life. They are not a cure, because nothing can rebuild a damaged optic nerve, but they slow or halt the progression of the disease very effectively for most people. Laser treatments and surgical options exist for cases where drops alone are not enough.
The honest truth is that outcomes depend a lot on how early the condition is caught. Patients diagnosed in the early stages, with mild nerve damage, generally retain useful vision for the rest of their lives. Patients diagnosed late, with advanced damage, may need ongoing support and adjustments to maintain quality of life. The window matters, which is the entire reason a regular eye test exists.
We will keep monitoring you ourselves between hospital visits, and we will make sure you understand exactly what is happening and why. Continuity of care is something we take seriously at Brittain Opticians. You will see the same team year after year, and we will know your eyes and your history. You can learn more about our approach and the team if you want a sense of who you would be working with.
Reducing Your Risk, Sensibly
You cannot change your age, ethnicity, or family history, but there are still things worth doing. Regular eye tests are the single most powerful tool you have, because they catch the disease before symptoms appear. Beyond that, managing conditions like diabetes and high blood pressure properly, avoiding smoking, and getting reasonable exercise all support healthy blood flow to the optic nerve. Some research suggests that a diet rich in leafy greens may have a modest protective effect, though the evidence is not as strong as people sometimes claim.
UV protection matters for general eye health, even if its direct link to glaucoma is less established than it is for cataracts. A decent pair of sunglasses, worn whenever the sun is bright, is one of the easiest investments you can make in your long-term sight. Have a look at our full range of services if you would like to see what we offer alongside eye tests.
For an excellent independent resource on glaucoma, risk levels, and what to expect at every stage, Glaucoma UK is the charity we recommend most often. Their helpline is genuinely useful if you or a family member has just been diagnosed.
Looking After the Sight You Have
Glaucoma is not a disease to lose sleep over. It is a disease to take seriously and act on early. Half the people who have it do not know yet, and the only reason that statistic exists is because too many people skip the eye test that would have caught it. A 40-minute appointment, every year or two, is often all that stands between most people and an avoidable loss of sight.
If you are over 40, especially if a parent or sibling has had glaucoma, treat your next eye test as a priority rather than a “when I get round to it.” If you are under 40 but have noticed anyone in this guide describing you, the same applies. Glaucoma is rare in younger adults, but it is not impossible, and the rules about who pays attention should be guided by risk, not just age.
A sensible plan looks like this:
- Check whether you qualify for a free NHS sight test, particularly if you are 40+ with a family history of glaucoma.
- Book your eye test now if you are due one, or sooner if you have higher-risk factors.
- Bring along any previous prescriptions and tell us about any family eye history when you arrive.
- Stick to the testing interval your optometrist recommends. Yearly checks sound frequent, but they are the single most reliable way to catch glaucoma before it costs you sight.
We have been looking after eyes on Harborne High Street for over 80 years, and our 40-minute examinations and digital retinal imaging are designed to catch exactly the kind of quiet, creeping problems that glaucoma represents. If you would like to chat through any of this first, get in touch with us, and we will happily answer your questions. Otherwise, you can book your appointment online at a time that suits you.
Your sight is worth protecting before you notice anything is wrong. That is the whole point.
