Acute Angle-Closure Glaucoma

Go straight away if you suddenly have [1][2][3]:

• severe pain in or around the eye
• a red eye
• blurred or misty vision
• haloes or rainbow-coloured rings around lights
• a headache, often on the same side as the painful eye
• feeling sick or vomiting

It can fool people. Because of the headache and vomiting, an attack is sometimes mistaken for a migraine, a stomach upset or "masuk angin". If someone has a headache with vomiting and a red, painful eye with blurred vision, think of acute glaucoma.

Attacks often start in dim light (for example, in the evening, in a cinema or while using a phone in a dark room), or after eye drops that make the pupil big, or after some medicines (see below) [1].

Milder warning attacks: some people have short episodes of blurred vision, haloes and an aching eye that go away on their own, often after sleeping. These still need an urgent eye check, because a full attack may follow [1].

Your eye is always making a clear fluid. The fluid drains out through a tiny drain in the angle, where the coloured part of the eye (the iris) meets the clear window at the front (the cornea).

In some people, this angle is very narrow. If the iris is pushed forward and blocks the drain completely, fluid cannot get out. The pressure inside the eye goes up very quickly, often to very high levels. This is an acute angle-closure attack.

Image to add

Side-by-side diagram of the front of the eye: on the left, an open drainage angle with fluid flowing out; on the right, the iris bulging forward and blocking the angle. Alt text: "Diagram comparing an open drainage angle with fluid draining normally, and a closed angle where the iris blocks the drain."

This is different from the more common open-angle glaucoma, which is slow and painless. You can read more about the types of glaucoma on our glaucoma page.

What causes it?

The main cause is the shape of the eye. Some eyes have a narrow angle and a crowded front part. With age, the natural lens inside the eye gets thicker, which pushes the iris forward and makes the angle even narrower [1].

An attack can be triggered when the pupil becomes medium-sized or big, which bunches up the iris in the angle. Triggers include [1]:

• dim light or darkness
• eye drops that dilate (widen) the pupil, used for eye checks
• some medicines, for example some cold, flu and allergy medicines (decongestants and antihistamines), medicines with anticholinergic effects (used for some bladder, stomach or mental health problems), and topiramate (used for epilepsy or migraine)
• stress

If you have been told you have narrow angles, check with a doctor or pharmacist before taking new medicines, and remind them about your eyes.

Your risk of angle closure is higher if you [1]:

• are of East or Southeast Asian descent, including people in Brunei
• are a woman
• are older, usually over 50
• are long-sighted (hyperopia), so you have a smaller eye with a crowded front part
• have a parent, brother or sister with angle-closure glaucoma
• have been told by an eye doctor that you have narrow angles

Worldwide, angle-closure glaucoma is most common in Asia [4].

During an attack, the signs are usually strong and obvious (see When to get help urgently). At the hospital, the eye doctor will:

• check your vision
• measure your eye pressure
• look at the front of the eye with a microscope (slit lamp)
• look at the drainage angle with a special lens (gonioscopy), once the eye is calmer
• check the other eye, which often has a narrow angle too

Narrow angles without an attack cause no symptoms. They are often found during a routine eye check.

What can happen?

The very high pressure damages the optic nerve (the cable from the eye to the brain) and other parts of the eye. Without fast treatment, it can lead to:

• permanent loss of sight, which can happen within hours to days [1]
• long-term (chronic) glaucoma
• a cloudy cornea or damaged iris

The other eye is also at high risk of an attack, because both eyes usually have the same shape. This is why both eyes are treated [1].

Step 1: bring the pressure down fast [1]

• Eye drops to lower the pressure and calm the eye
• Tablets and sometimes a drip (intravenous medicine) to bring the pressure down quickly
• Pain relief and anti-sickness medicine

Step 2: stop it happening again [1]

• Laser peripheral iridotomy: a laser makes a tiny hole in the edge of the iris, so fluid has another way to flow and the angle can open. It is done in the clinic and takes a few minutes.
• This is done to the affected eye once it has settled, and also to the other eye to prevent an attack there.

Sometimes [1]

• Lens extraction: removing the eye's natural lens (the same operation as cataract surgery) makes much more space in the front of the eye and opens the angle. This may be advised, especially if you also have a cataract.
• Some people still need long-term glaucoma drops, laser or surgery if the pressure stays high or the optic nerve is damaged.

You will need regular follow-up with the eye clinic after an attack.

• Know the warning signs and go to Emergency straight away if they happen.
• Have an eye check if you are over 40, especially if you are long-sighted or have family members with glaucoma. Narrow angles can be found before an attack, and a laser can lower the risk [1].
• If you have been told you have narrow angles, follow your eye doctor's advice about laser treatment, and ask before taking cold, allergy or other new medicines.
• If you have had an attack, tell your brothers, sisters and children to get their eyes checked.

Where to get help in Brunei

For a sudden painful red eye with blurred vision, go to the hospital Emergency Department now. Do not wait for a clinic appointment.

For a routine eye check, for example to look for narrow angles, you can walk in to a Community Eye Clinic at your health centre. No referral is needed.