If you have healthy eyes, the fluid in your eye (aqueous 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, the access for aqueous fluid to escape the eye can become obstructed by the iris (the coloured part of your eye) which has moved forward. This can cause your eye pressure can continue to rise and can cause a permanent loss of side (peripheral) and central vision. An iridotomy allows fluid to circulate freely within the eye and so will minimise the risk of a sight-threatening pressure rise.
What is a laser peripheral iridotomy?
An iridotomy is a small hole created with a laser beam in the outer part of the iris (coloured part of the eye). This forms a permanent passage through which aqueous humour can flow through and pushes the iris tissue backward, thus unblocking the drainage channels.
Aqueous humour is a completely different fluid to your tears – they will not be affected by the operation.
What are the benefits of having a laser iridotomy?
It is important to remember that this procedure is performed to preserve 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.
The three reasons for the YAG laser peripheral iridotomy are:
To prevent an attack of acute angle closure
To treat an attack of acute angle closure
To treat chronic glaucoma where the drainage channel is very narrow
Are there any alternatives?
An alternative to laser treatment is a surgical lens extraction cataract operation (a procedure which is technically identical to cataract surgery) compared to laser peripheral iridotomy, although the risk is still low (less than 1 in 1000). For this reason, lens extraction is usually only recommended for patients who are already developing visual problems from cataract, or for patients who are unlikely to benefit from laser treatment.
Patients who choose not to have laser peripheral iridotomy or lens extraction treatment risk developing angle-closure or deterioration of established angle-closure, which can result in high intraocular pressure and loss of vision from glaucoma. Observation only, is a reasonable option for patients who do not have high intraocular pressure or other signs of damage from angle-closure and we would recommend having regular reviews by a local optometrist.
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.
Are there any risks associated with a laser iridotomy?
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. We 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, we 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.
A small number of patients find that extra light enters through the new opening, which can be a little distracting at first and cause glare. However, most patients find they are soon able to ignore this.
Other complications are haemorrhage in the eye, which will blur your vision for a few days or your eye may feel slightly bruised afterwards because of inflammation – this is usually small and can be treated with more frequent steroid drops.
Discomfort - You may wish to take a mild painkiller, for example Paracetamol, to relieve this discomfort. If you are already taking painkillers for a different condition continue with these, but do not take both.
Certain symptoms could mean that you need to be treated quickly, including:
loss of vision
your eye becoming increasingly red.
If you experience any of these symptoms, telephone us for advice immediately. Or visit your nearest accident and emergency department.
How successful is laser iridotomy?
Laser iridotomy is very good at protecting against acute angle closure glaucoma.
Occasionally the small hole can partly or completely heal up in the first few days after the laser treatment. Further laser treatment may be necessary following your review in clinic. This is usually very successful.
What do I need to do to prepare for laser treatment?
As this is an outpatient treatment, you can eat and drink as normal. You must take your regular eye medication and diet as normal on the morning of the laser treatment (unless instructed not to).
The treatment itself should take about 15 minutes, but you are likely to remain in clinic for 1-2hours.
What happens on the day of treatment?
Upon arrival, we will explain the procedure, and ask you to sign a consent form.
As always, remember to bring a list of your current medications with you to the appointment.
We will then l check your vision and put some drops into your eye to make your pupil smaller and prevent the pressure rising within your eye. The drops take up to one hour to work.
A few minutes before the treatment, you will have anaesthetic eye drops put into your eye to gently numb the surface of the eye.
Once seated you will then be asked to rest your chin in front of the laser machine, which is similar to the microscope you will have been examined on in clinic. A special contact lens will be placed against the front surface of your eye to help keep your eye still and to focus the laser beam.
We will carefully direct a laser beam into your eye. You will see a series of bright lights and you will hear a clicking noise while the treatment is being carried out.
It is very important that you sit and keep your head still during the treatment to avoid damage to other parts of the eye.
You may feel slight discomfort, but the treatment is generally painless and should take up to 15 minutes.
After the procedure
Your vision may be slightly blurred for a few hours following your laser treatment. This will settle.
For this reason it is strongly advised that you do not drive home yourself. However, apart from driving, you can resume all other normal activities immediately
After the laser treatment, you will have further drops put in your eyes to help reduce any inflammation caused by the laser. The pressure in your eye will be checked about an hour after the treatment. You may then return home. You will then receive a prescription for drops to take at home and an appointment to come back to the clinic for a review.
An important reminder
You should continue to use all your anti-glaucoma medication unless specifically instructed otherwise.