Primary angle closure

This leaflet explains more about how to recognise and treat primary angle closure glaucoma. If you have any further questions, please speak to a doctor or practitioner caring for you.

What is glaucoma?

Glaucoma is a term that describes a group of eye conditions that affect vision. When the eye is functioning normally, fluid is produced inside the eye and is then drained away through the drainage channel. The balance between the production and drainage of the fluid creates a normal amount of pressure in the eye, which is needed for the eye to maintain its shape and function. If the fluid cannot drain away properly, the pressure in the eye rises. If the pressure is too high, the optic nerve at the back of the eye becomes damaged. The diagnosis of glaucoma is given when there is evidence of optic nerve damage.

What is primary angle closure?

The most common type of glaucoma is called primary open angle glaucoma. This is when the drainage channel (located between the iris and the cornea) is open. When the drainage channel closes, the iris moves forwards and against the cornea, blocking the pathway to the drainage channel and causing the pressure in the eye to rise. If this pressure remains high for a period of time, the optic nerve can be damaged, which then leads to primary angle closure glaucoma. There are a number of conditions that are closely related to primary angle closure:

Primary angle closure suspect – This is when tests show that the drainage channel in your eye is narrow and is at high risk of closing up at any time. This is more common in people with smaller shaped eyes where the iris is naturally closer to the cornea.

Acute angle closure – Primary angle closure is usually painless and occasionally causes symptoms of mild headache. However, if the drainage channel suddenly closes and the pressure suddenly becomes very high, the signs and symptoms are usually severe. This is called acute angle closure.

What are the signs and symptoms of acute angle closure?

It is possible to experience an acute angle closure attack if you have been diagnosed with primary angle closure suspect or if you have primary angle closure and are waiting for treatment. It is therefore very important that you are aware of the signs and symptoms of an angle closure attack. Symptoms include: intense pain of the eye sore or tender eye area headache redness of the eye blurred and reduced vision seeing coloured haloes around lights.

What should I do if I am experiencing any of these symptoms?

If you are experiencing any of these symptoms, you should seek medical advice as soon as possible. You can attend the eye casualty in the South Wing of St Thomas’ Hospital between 8.45am to 4.00pm, Monday to Friday. Outside of these hours, you should attend the St Thomas’ accident and emergency (A&E) department. If you do not live near St Thomas’ Hospital, you should attend a local hospital with an eye casualty unit.

What treatment is available for primary angle closure?

The two main treatment options are laser peripheral iridotomy and cataract extraction surgery.

Laser peripheral iridotomy

In this procedure, a laser beam is used to create a small hole in the iris. This provides another route for the fluid to flow and pushes the iris backwards, in turn helping to open the drainage channel. For more information on this procedure, please read the Having a laser peripheral iridotomy information sheet. If you do not have a copy of this leaflet, please ask the nurse or doctor caring for you.

Cataract surgery

When a cataract forms, the lens inside your eye slowly becomes thicker. This can push the iris forwards, causing the drainage channel to become narrower. In a cataract operation, the natural lens is removed and replaced by a thin artificial lens. This makes more room for the iris to move backwards and allows the drainage channels to open. For more information on this procedure, please ask for the Cataract surgery information leaflet.

Both procedures are effective in the treatment of primary angle closure. Your doctor will discuss with you the treatment that is best for you.

You may be prescribed glaucoma medication in the form of drops and/or tablets, which should be taken daily to control your eye pressures until the day of your procedure. Your eye pressures may remain high even after the procedure. In these instances, drops may be needed to lower the eye pressures forever.

What happens if I do not get treatment?

If the pressure in the eye remains high, extensive damage can occur to the optic nerve. This will lead to significant and permanent visual loss. Having a laser peripheral iridotomy

What is a laser peripheral iridotomy?

A laser peripheral iridotomy is a treatment used to treat angle closure.

If you have healthy eyes, the fluid in your eye (aqeous humour) flows through your pupil into the front of your eye, and drains away through drainage channels called the trabecular meshwork.

However, if you have angle closure, these drainage channels are obstructed by the iris (the coloured part of your eye) which has moved forward. Because of this, aqueous humour cannot leave your eye, so your eye pressure increases (also known as intraocular pressure).

The build -up of pressure injures your optic nerve – the nerve that carries information from your eye to your brain – and damages your vision.

A peripheral iridotomy uses a laser beam to create a small hole in your iris. This forms a permanent passage through which aqueous humour can flow through and pushes the iris tissue backward, thus unblocking the drainage channels.

Laser makes hole in iris Contact lens to focus laser beam Fluid drains through hole and out of eye Reproduced with permission from Patient Pictures: Ophthalmology, Health Press, Oxford 2001. Illustrated by Dee McLean Aqueous humour is a completely different fluid to your tears – they will not be affected by the operation.

What happens during a laser peripheral iridotomy?

You will need to visit the outpatient department for about half a day. We will carry out the treatment in one of our laser treatment rooms. You do not need to do any special preparations such as fasting or changing into operating theatre clothes.

The doctor or nurse will assess your eye first, and check the pressure. It is important that you use your regular eye medication drops as normal on the morning of your laser treatment (unless your doctor has told you otherwise).

You will then have some more drops put into your eye. These will usually be a miotic (a drop to make your pupil smaller), a drop to lower the intraocular pressure (the pressure inside your eye due to aqueous), and an anaesthetic eye drop to numb your eye.

You will then sit at a machine similar to the machine used to examine your eyes at the eye clinic. However, there is a special laser attached to this machine.

The doctor will put a special contact lens on your eye before applying the laser beam. This lens allows the doctor to view your iris clearly so he or she can apply the laser and make the hole in your iris.

The treatment is painless due to the anaesthetic drop used to numb your eye before the laser, but you might get a slight discomfort when the laser is being applied. This takes about 20 minutes.

After the procedure, you will return to the waiting area. Your doctor or nurse will check the eye pressure about one hour later. He or she will then examine the eye to check the newly formed opening is working well.

What are the benefits?

It is important to remember that this procedure is performed to save the sight you still have. It will not restore any sight you may have already lost; neither will it improve your sight.

The laser treatment is to prevent a sudden (acute) rise in pressure within your eye. Without having this treatment, you are at risk of developing sudden glaucoma and irreversible blindness.

Are there any risks?

Complications after this treatment are uncommon. Occasionally your eye pressure will rise immediately after laser treatment. If this happens, you may need extra treatment before you can go home.

This treatment usually comes in the form of eye drops, but may come in the form of tablets. Your doctor will let you know which treatment you need and will advise you of how long you need to take the treatment for.

If we do treat you with eye drops, a doctor or nurse will put them in your eye before you leave hospital. You will be asked to remain in the department until your eye pressure has reduced to a satisfactory level. This should take a few hours at most.

Occasionally the laser beam opening is incomplete, or not big enough. This will be discovered either after your treatment, or on your follow-up visit. If this is the case, we will have to repeat the treatment at a later date.

A small number of patients find that extra light enters through the new opening, which can be a little distracting at first. However, most patients find they are soon able to ignore this.

Other complications are haemorrhage in the eye from the laser and inflammation – this is usually small and can be treated with more frequent steroid drops.

If you experience any of these symptoms, visit your nearest eye emergency department.

Are there any alternatives?

An alternative to laser treatment is a cataract operation, which is not suitable for everyone. It also carries a greater risk of complications. There are no other alternatives to open up the drainage channels in your eye. Some patients with this condition also develop a long-term (chronic) rise in their eye pressure. In this case, you may need drops or other treatments in the long-term to keep your eye pressure within safe limits.

What do I need to do to prepare?

As this is an outpatient treatment, you can eat and drink as normal. You must take your eye medication as normal on the morning of the laser treatment (unless instructed not to).

Asking for your consent

We want to involve you in decisions about your care and treatment. If you decide to go ahead, you will be asked to sign a consent form. This states that you agree to have the treatment and you understand what it involves. If you would like more information about our consent process, please speak to a member of staff caring for you. No treatment is carried out without your consent unless it is an emergency and you are unconscious.

What happens after the procedure?

You will be seen in the outpatient department a week or two later to make sure your eye has responded well to treatment. You will have another check-up to see if the treatment was successful. You should be given a follow-up appointment before you leave the hospital after your treatment.

If you have discomfort once you get home, we suggest that you take your usual pain reliever following the instructions on the packet.

It is normal to have gritty, sticky eyelids and mild discomfort for a couple of hours after laser treatment. The eye drops can also take some time to wear off, and you should not be alarmed if your pupils are still small for several hours after treatment.

The drops can also cause a mild to moderate headache across your brow. Because they make your pupil small, you might find that a dim or dark room is quite dark. Do not panic. The drug will have worn off by the morning, and your pupils should be back to their normal size again.

You may also find that your vision is a little blurred. This is normal, and your vision should return to how it was before the laser by the end of the day.

What do I need to do after I go home?

We may prescribe anti-inflammatory drops after your laser treatment. These help to minimise inflammation (but not infection) within the eye. People normally only have to take these for a week at most – the doctor will tell you how long you need to take them for. You do not need antibiotics because your eye doesn’t have an open wound.

If you are using glaucoma drops, please check with the nurse or the doctor whether or not you need to continue using them on your treated eye. It is usual to continue using them unless your doctor has said otherwise. If you are using glaucoma drops to the untreated eye, please continue to use them unless clearly instructed otherwise. You can do all of your daily activities as you would normally without any problems.