Patient Information

Eye surgery leaflets

Eye Department
Ipswich Hospital
Tel: 01473 703 230


Laser iridotomy


What is a laser iridotomy?

A laser iridotomy involves making a tiny hole with a laser beam in the iris (coloured part of the eye).


Why is a laser iridotomy performed?

An iridotomy is performed to prevent or treat acute angle closure glaucoma (AACG) or used for people with primary angle closure glaucoma (PACG).


What is primary angle closure glaucoma (PACG)?

In PACG, the ‘drainage angle’, which is the gap between the cornea (clear window of the eye) and the iris, is narrower than normal and there is a risk that the iris can press against the cornea and block the trabecular meshwork.

The trabecular meshwork is the sieve-like structure that runs around the edge of the iris to allow drainage of the fluid (aqueous) in the front of the eye (see diagram below).

The iris can then stick to the surface of the lens, completely blocking the flow of aqueous fluid. This causes acute angle closure glaucoma, resulting in severe eye pain and blurred vision.


Diagrams of the eye, showing the iris pushed forward onto the trabecular meshwork, and the laser iridotomy position


What does the procedure involve?

An eye drop called pilocarpine is put into the eye to make the pupil small. This stretches the iris and makes it easier for the laser beam to penetrate. Pilocarpine may give you a headache and blur your vision.

Local anaesthetic drops are then instilled to numb the front of the eye, and a special contact lens is placed on the surface of the eye to direct the beam of light from the laser.

The laser looks like the microscope (slit lamp) that you will have been examined on in the clinic or at the opticians.

Laser spots are applied to the iris to make the tiny hole for the fluid to drain through, allowing it to flow into the front part of the eye (see diagram). The hole is microscopic and is normally under the upper lid, so it is not visible.

The procedure only takes a few minutes, but you need to keep as still as possible.


What happens afterwards?

Your vision will be blurred for a few hours and you may have some discomfort or headache. Please take your usual pain relief medication.

You will be given a prescription for anti-inflammatory eye drops to use as a short course after the procedure (usually 5–7 days).

You can resume normal activities, but please do not drive until your vision has returned to normal and you feel safe to do so.

You will need to be seen in the Eye Clinic approximately 6–8 weeks after the procedure.


Are there any possible complications?

Some people find their vision is blurred following the procedure. This normally clears in 24–48 hours, but may take longer. Other less common complications include swelling of the clear window (cornea) of the eye, bleeding inside the eye and raised intra-ocular pressure. Very rarely, there may be a burn to the inner lining of the eye (retinal burn).

Later complications that may develop include worsening of any cataract that was present before laser treatment, closure of the opening, recurrent angle-closure glaucoma, development of a secondary glaucoma and glare from light entering through the new opening

If you have any problems such as a sudden deterioration or change in vision, or severe pain in the eye, please contact us:

  • Monday to Friday, 9am–5pm (excluding bank holidays), please telephone 01473 703 178. You will be able to speak to the ophthalmic triage nurse
  • Monday to Friday, 5pm–midnight; weekends and public holidays, 8am–midnight, please telephone 01473 712 233, choose the option for the operator and ask to speak to the on-call ophthalmologist. You will be able to speak to a doctor
  • Outside these hours, please call 111 or go to your nearest Emergency Department.



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