Dr Jayant V Iyer, Dr Jason Lee and Dr Audrey Pang at the reception of The Straits Eye Centre.

Glaucoma in Singapore

Glaucoma is painless until it is advanced, and the sight it takes does not come back — which is why it is found by examination, not by symptoms.

Eye pressure and optic nerve checked together
Treated by a senior eye specialist
Six clinics in five locations islandwide

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Camden (Orchard)Joo ChiatClementiBedokToa Payoh

Found before you would notice it

The common form takes side vision first, so it is picked up on examination rather than by symptoms.
Treated to protect the sight you have

Nerve already lost cannot be restored, so treatment aims at the vision that remains and is reviewed over time.
Six clinics in five locations

Consultations and follow-up across the island, with your results explained to you in person.

Medically reviewed by Dr Jayant V Iyer MBBS · GDFM · MMed (Ophth) · FRCOphth · FAMS

Last updated 6 September 2026

What glaucoma is

Glaucoma is damage to the optic nerve, the cable of about a million fibres that carries what you see from the eye to the brain. It is usually linked to the pressure of the fluid inside the eye being too high for that particular nerve to tolerate. Fibres are lost gradually, and the vision they carried does not come back.

That last point is what separates glaucoma from most of what an eye clinic sees, and it is why the whole subject is organised around finding it early. There is no ache, no red eye and no blurring in the common form. Sight is lost from the edges inward, where the other eye covers the gap, so a person can lose a great deal of field before anything feels wrong.

It is not one disease. Open-angle glaucoma is the common form and the silent one: the eye's drainage angle stays open but drains too slowly, and pressure creeps up over years. Angle-closure glaucoma is less common and can come on suddenly, with pain, redness, haloes around lights and nausea — that version is an emergency and belongs in a hospital the same day, not in a search result.

Age is the largest risk factor, which is why a baseline eye examination is recommended at 40. Risk is higher again with a family history of glaucoma, short-sightedness, diabetes, a previous eye injury, or long-term steroid use.

Eye pressure, and what counts as high

The number a clinic gives you is intraocular pressure, measured in millimetres of mercury. It is the most talked-about figure in glaucoma and the most often misread.

Most eyes measure between 10 and 21 mmHg. It is tempting to treat 21 as a line with health on one side and disease on the other, and that is not how it works: the range describes what is common in a population, not what is safe in your eye.

Two things follow from that, and between them they are the reason a pressure reading on its own does not diagnose or exclude glaucoma. Some optic nerves are damaged at pressures well inside the ordinary range. Many eyes sit above it for years and are never damaged at all. What matters is the pressure this nerve will tolerate, which is judged by looking at the nerve and testing the field of vision as well as taking the reading.

Normal eye pressure

Roughly 10 to 21 mmHg, with the optic nerve and the field of vision both intact. Nothing to treat.

Ocular hypertension

Pressure above the usual range with no nerve damage yet. Not glaucoma, but watched, and sometimes treated to keep it that way.

Normal-tension glaucoma

Nerve damage at a pressure that measures inside the ordinary range. It is the case that a pressure check alone would miss.

Why glaucoma is usually silent

What people expect to notice, and what there actually is to notice.

In open-angle glaucoma there is generally nothing to feel. Vision is not blurred, the eye is not sore or red, and reading and screen work are unaffected until late. The loss is in the field around what you are looking at, and it arrives so slowly that the brain fills it in.

Where something is noticed, it tends to be one of these, and each of them is worth an examination rather than a wait:

Missing patches to the side, or catching door frames and kerbs on one side
Needing more light to read than you used to, or trouble adjusting between bright and dim rooms
Difficulty judging steps and kerbs, particularly at night
Trouble driving that does not improve with a new spectacle prescription

The exception is the acute form. Sudden eye pain with redness, haloes around lights, a headache and nausea is not something to book an appointment for — that is a same-day hospital presentation, and treatment within hours is what protects the eye.

Glaucoma and cataract: how they differ

They are often confused, they are both common after 60, and plenty of people have both at once. They are not versions of the same thing.

Glaucoma and cataract compared: what goes wrong, what you notice, which vision is affected, whether it can be reversed, what treatment does and how each is found.
What is compared	Glaucoma	Cataract
What goes wrong	The optic nerve is damaged, usually by pressure inside the eye.	The eye’s natural lens clouds, mostly with age.
What you notice	Usually nothing, until a lot of side vision has gone.	Misty or dulled vision, glare at night, colours washing out.
Which vision goes	Side vision first, from the edges inward.	Central and general clarity — the whole picture dims.
Can it be reversed	No. Lost nerve does not recover.	Yes. Surgery replaces the clouded lens.
What treatment does	Lowers the pressure to protect the vision that remains. Usually lifelong.	Removes the cause. A cataract does not grow back afterwards.
How it is found	Pressure, optic nerve and visual field checked together.	Seen directly on examination of the lens.

The row that matters is the fourth one. A cataract postpones sight and an operation gives it back; glaucoma takes sight permanently, a little at a time, and treatment holds the line where it currently is. That is the whole reason the two are approached so differently — one can reasonably be watched until it bothers you, and the other cannot.

Having both is common, and neither rules out treating the other. If a clouded lens is what is blurring your vision, how a cataract is treated sets out what that operation involves.

How glaucoma is found

No single test settles it. The diagnosis comes from reading several together, which is why a pressure check at a spectacle counter is a starting point rather than an answer.

A glaucoma assessment looks at the pressure, the nerve itself and what the nerve is still doing. Each of the four below answers a different question, and it is the combination that distinguishes an eye with high pressure and no disease from an eye with normal pressure and real damage.

Tonometry — measures the pressure inside the eye. The number people mean when they say “eye pressure”.
Optic nerve examination — looks at the head of the nerve for the hollowing that pressure damage produces, often photographed so it can be compared later.
Visual field test — maps the side vision the common form takes first, and finds loss well before you would notice it.
Imaging of the nerve fibre layer — measures the thickness of the fibres directly, which can register thinning before a field test does.

Two of these are the reason a routine check is worth booking when nothing is wrong. If you want the checks that come as a package, our eye screening appointment options set out what each one includes and who each is for.

How glaucoma is treated

The aim is the same whichever route is taken: bring the pressure down to a level this nerve tolerates, and keep it there.

Because lost nerve cannot be recovered, treatment is about the vision you still have. Glaucoma is generally managed with daily eye drops, laser, or surgery, alone or in combination, and it is normally continued for life with regular review to confirm the field of vision is holding.

Which of those suits an eye depends on how high the pressure is, how much damage is already there, how fast it is moving and how the eye responds — so it is settled at an examination and not in advance. Glaucoma is treated at The Straits Eye Centre. Dr Jayant V Iyer, Senior Consultant Eye Surgeon and Medical Director, holds glaucoma as his subspecialty.

If you have been told your pressure is high, or a relative has glaucoma and you have never been checked, that is a reason to see an eye specialist rather than watch for symptoms — because in the common form there are none to watch for.

I have a question about glaucoma

Send us a message about where you are with it, and we will arrange the right next step.

I was told my eye pressure is high Glaucoma runs in my family I want my optic nerve checked I would like a second opinion

Common questions

What are the first signs of glaucoma?

Usually there are none. The common form is painless and takes side vision first, which the other eye compensates for, so many people notice nothing until a substantial amount of nerve has already been lost. That is why it is found on an eye examination rather than by symptoms.

Is glaucoma the same as a cataract?

No. A cataract is clouding of the lens inside the eye and the sight it costs you can be restored by surgery. Glaucoma is damage to the optic nerve, and the sight it costs you does not come back. You can have both at once, and they are treated separately.

What is a normal eye pressure?

Most eyes measure between 10 and 21 mmHg. That range is a guide rather than a dividing line: some eyes are damaged at pressures inside it, and many eyes above it are never damaged at all, which is why pressure alone does not diagnose glaucoma.

Can you have glaucoma with normal eye pressure?

Yes. It is called normal-tension glaucoma, and the optic nerve is damaged at a pressure that measures in the ordinary range. It is one of the reasons an eye examination looks at the optic nerve and the field of vision rather than at the pressure reading alone.

Can glaucoma be cured?

No, and no treatment restores nerve that has already been lost. What treatment does is lower the pressure inside the eye to protect the vision you still have, which is why it is usually continued for life and reviewed regularly.

Does glaucoma always lead to blindness?

No. Most people diagnosed and treated keep useful vision for the rest of their lives. The risk sits with glaucoma that goes unfound, because the early loss is in side vision and is easy to miss.

Who should be checked for glaucoma?

Risk rises with age and is higher with a family history of glaucoma, short-sightedness, diabetes, previous eye injury and long-term steroid use. A baseline eye examination is recommended at 40 even when nothing feels wrong.