Laser Peripheral Iridotomy

Patient Experience

  • Reference Number: HEY-264/2021
  • Departments: Ophthalmology Department
  • Last Updated: 16 September 2021


This leaflet has been produced to give you general information about your laser treatment. Most of your questions should be answered by this leaflet.  It is not intended to replace the discussion between you and your doctor but may act as a starting point for discussion.   If after reading it you have any concerns or require further explanation, please discuss this with a member of the healthcare team caring for you.

What is a YAG Laser Peripheral Iridotomy?

A “laser” is a type of focused light made by a special machine.  Using this laser, your doctor makes a small hole in the iris (Iridotomy).  This is generally done in the far edge (periphery) of the top part of the iris that is hidden under the upper eye lid. Sometimes the laser surgeon may choose to place the laser hole in a different location (rather than at the top).

The aim of the hole is to help assist aqueous fluid to flow from one side of the iris to the other and then out of the eye through the trabecular meshwork (an area of tissue in the eye located around the base
of the cornea). This laser treatment is recommended, as it will dramatically reduce the chance of developing acute glaucoma in those patients who are at high risk of developing the sudden rise in pressure in their eye. However, despite this laser treatment, it is possible that you could still get chronic glaucoma.

Why do I need a Yag Laser Iridotomy

The eye is normally filled with fluid. This fluid drains out of the eye through a structure called the trabecular meshwork, which lies in front of the iris (the coloured part of the eye).

If the drainage of fluid is blocked for any reason, the pressure in the eye (intra-ocular pressure) increases. High pressure in the eye can damage the nerve of the eye and lead to loss of vision.

The blockage can:

  • Happen suddenly – this is called Acute Glaucoma and happens if the iris flops forward and completely shuts off access to the trabecular meshwork.
  • Happen gradually – this is called Chronic Glaucoma, if the trabecular meshwork itself “furs up”.

More information about Glaucoma is available in a booklet called ‘Glaucoma’ available from the Royal National Institute for the Blind, copies of which are available in the Eye Clinic and also from the ‘International Glaucoma Association’.

Can there be any complications or risks

As with any procedure, there are always potential complications that could occur.  The most common or serious that you should know about are:

  • Intra-ocular pressure problems that may need medication (eye drops and/or tablets) or sometimes surgery to treat.
  • Inflammation inside the eye is common after the laser and you will be given some drops for this. This is usually only for a short time following the procedure until the eye settles.
  • The laser can cause bleeding inside the front of the eye, which can temporarily blur the vision in the eye, as well as causing inflammation and causing the eye pressure to go up. In most cases, the blood generally goes away by itself within a few weeks.  Pressure and inflammation changes can be treated by medication if required.
  • You may develop double, blurred, or worse vision as a result of light passing through the hole that has been made by the laser, although this is uncommon. This can sometimes be managed with a contact lens designed to block light passing through the hole but the problem may be permanent.
  • Glare and ‘lines’ in the vision can sometimes be noticed in the treated eye following this procedure.
  • A cataract (cloudiness of the lens) may develop quickly in the eye that received laser treatment. If this occurs, the cataract can be managed in the same way as other cataracts.
  • There is also a chance of damage to the bag that holds the lens or cataract (the lens capsule). This may result in early surgical removal of your lens or cataract.
  • Occasionally, vision may become more blurred due to retinal swelling at the back of the eye (Cystoid macular oedema). This may require further treatment with drops and tablets.
  • Trauma to the cornea (clear window at the front of the eye) can occur from the contact lens used during the procedure, or from the laser energy. However, this is rare and usually causes little trouble in the long term.
  • The pupil (black hole in the middle of the iris) can develop an irregular shape following the procedure.
  • There is a small risk of developing a retinal detachment, which would require surgery and may threaten the eyesight.
  • Sometimes the hole we make can scar or close up. This would require another laser procedure to be carried out where a new hole would be made, or the existing hole widened.
  • It can sometimes be difficult to perform this procedure on patients with dark coloured eyes and it may be necessary to perform a different type of laser on the eye first to make this procedure easier. It may also be necessary to have this procedure performed more than once to ensure a wide enough hole is created.

Although the above complications do occur, we take every precaution to reduce the risks and aim to give the minimum treatment necessary.

How do I prepare for the laser treatment?

Please read the information leaflet. Share the information it contains with your partner and family (if you wish), so that they can be of help and support. There may be information they need to know, especially if they are taking care of you following this treatment.

There are no specific instructions that you need to follow prior to this laser treatment. The treatment is carried out in the Eye Outpatient Department.

You should not drive to and from the appointment and should not drive for 24 hours.

What will happen?

  • Report to the Eye Hospital Reception where you will be directed to the Eye Clinic waiting area.
  • You can expect to be in the Eye Clinic for up to 2 hours.
  • A member of the nursing team will then check your vision (please bring with you your normal distance and reading glasses).
  • Before the laser, you may be given eye drops to make your pupil small.
    This makes the laser procedure easier to do safely. These drops may give you a headache. The effect of these drops only last for a few hours.
  • When the drops have had time to take effect you will be shown into the consulting room where the doctor will explain the procedure and gain your written consent.
  • As with previous examinations, you will sit in front of a microscope with your chin on a rest.
  • A local anaesthetic drop is given to numb the eye before a contact lens is placed over the eye.
  • You may also be given some eye drops before and/or after the procedure to help lower the pressure in the eye, as the procedure can sometimes cause the pressure to increase slightly.
  • The laser makes a clicking noise and you may be aware of bright lights and colours. Slight discomfort may be experienced but it is usually mild and lasts for a short time.
  • If the hole made is too small, you may be asked to sit at the laser machine again, so that the doctor can enlarge the hole slightly.
  • The laser treatment usually takes 5 – 10 minutes per eye.

What happens afterwards?

Following the laser treatment:

  •  You will be asked to wait 45-60 minutes in order for the doctor to check that the eye pressure is fine after the procedure and that the hole made in the iris is large enough.
  • You should not drive for 24 hours following the treatment.
  • You will be given short-term eye drops to use at home for a few weeks after the laser procedure.
  • We will see you in clinic again after a few weeks to check the pressure in the eyes has stabilised and ensure that the holes made are working correctly.
  •  You may need to use eye drops to help control the eye pressure for the rest of your life; this will be explained at the follow up visit.
Should you require further advice on the issues contained in this leaflet, please do not hesitate to contact the Ophthalmology Department (01482) 816658 (08:30am – 17:30pm Monday-Friday) or (01482) 608788 or Out-of-Hours (01482) 604346 (Please listen to full voice message on how to access emergency out of hours service)

General Advice and Consent

Most of your questions should have been answered by this leaflet, but remember that this is only a starting point for discussion with the healthcare team.

Consent to treatment

Before any doctor, nurse or therapist examines or treats you, they must seek your consent or permission. In order to make a decision, you need to have information from health professionals about the treatment or investigation which is being offered to you. You should always ask them more questions if you do not understand or if you want more information.

The information you receive should be about your condition, the alternatives available to you, and whether it carries risks as well as the benefits. What is important is that your consent is genuine or valid. That means:

  • you must be able to give your consent
  • you must be given enough information to enable you to make a decision
  • you must be acting under your own free will and not under the strong influence of another person

Information about you

We collect and use your information to provide you with care and treatment. As part of your care, information about you will be shared between members of a healthcare team, some of whom you may not meet. Your information may also be used to help train staff, to check the quality of our care, to manage and plan the health service, and to help with research. Wherever possible we use anonymous data.

We may pass on relevant information to other health organisations that provide you with care. All information is treated as strictly confidential and is not given to anyone who does not need it. If you have any concerns please ask your doctor, or the person caring for you.

Under the General Data Protection Regulation and the Data Protection Act 2018 we are responsible for maintaining the confidentiality of any information we hold about you. For further information visit the following page: Confidential Information about You.

If you or your carer needs information about your health and wellbeing and about your care and treatment in a different format, such as large print, braille or audio, due to disability, impairment or sensory loss, please advise a member of staff and this can be arranged.

QR code to open leaflet