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Adult squint surgery

Patient information A-Z

What is a squint?

Squint is the term used when the eyes are not pointing in the same direction. Most commonly one eye either turns in or out. Occasionally one eye may be higher than the other.

If the eyes are not looking in the same direction then they are sending different signals to the brain and this can cause double vision.

The amount of squint can be measured and this is done by people who are trained in assessment of squints and their non-surgical treatment. These are called orthoptists.

Why do squints happen?

A squint can occur for a number of different reasons these include:

  • Damage to the muscles controlling the eye.
  • Damage to the nerves controlling the muscles.
  • Poor development or damage to the eye muscle control centres in the brain.
  • Poor vision in the eye can stop the brain being able to keep the eyes together. This occurs in adults who have had a squint as a child.

Why is it important?

A large squint can be a cosmetic problem. It can also cause double vision which can be very disabling. Double vision may also mean that you cannot drive.

Can squints be treated?

A full assessment of your eye and vision is performed and the cause of the squint is assessed.

If the squint comes and goes then it may be possible to watch and see if it gets any worse.

Sometimes it is possible to treat the squint with glasses or exercises.

If these do not work then it may be that we need to consider doing an operation to move the muscles that control the eye to a better position. This is to straighten the eyes up.

I need an operation so what happens next?

The angle of the squint needs to be measured and the movement of each affected muscle needs to be assessed.

The amount the eyes are working together is also assessed.

Your general health is discussed with one of our specially trained nurses and the details of the operation are discussed with one of the doctors. You will then be asked to sign a form to say that you understand the type of operation which is going to be performed.

Before surgery

You will be seen a few days before the date of surgery where final measurements of the squint are made. The doctor will go thorough the surgery in detail with you and answer all the questions you may have.

You will need to stop eating and drinking before surgery. When you stop will depend on the timing of the operation. This will be discussed with you at your pre-operative visit.

What happens on the day of surgery?

You will be seen by the anaesthetist who will discuss the anaesthetic with you. This will be a general anaesthetic so you will be asleep.

One or two eyes are operated on and the muscles will be either shortened or moved to a new position to straighten the eyes.

It may not be exactly right after one operation and sometimes a second operation is needed.

Adjustable sutures

In some adults who have squint surgery it may be more accurate to use adjustable stitches. The doctor will tell you if this is necessary.

The operation is performed while you are asleep and the stitch is tied in a bow at the end of the operation. You are then woken up and the eyes measured. If the eyes are not straight we can tighten up the muscle position using some drops to numb the eye. This makes the operation more accurate, especially for people who have already had a squint operation.

What happens after surgery?

You can go home once you have woken up properly. This is usually two to four hours after the operation.

The eye will feel gritty for around three to five days following surgery.

The eye may well look pink for up to ten weeks after surgery, but reduces as the weeks go by. You will be asked to take eye drops for two weeks.

A clinic appointment will have been made for a few weeks after the operation to check things are healing well.

The exact position of the eye will be fully assessed at a clinic appointment at the hospital, three months after the operation.


The aim of the operation is to improve the appearance of the squint by straightening the eyes, improve the control of eye movements and improve double vision if present.

Are there any risks?

Although most squint operations successfully straighten the eyes, all surgery carries risks and squint surgery is no different.

  • There can be some bruising on the eye which can make it look red.
  • Under or overcorrection of the squint, which may require further surgery.
  • Double vision. If double vision occurs, it often goes in the first week after surgery. If it is persistent, further surgery may be necessary.
  • Loss of vision. This is very rare; the vision in the operated eye can be made worse. This may be caused by bleeding inside the eye or infection.
  • If the eye is not quite straight after the operation it may settle by the three month appointment. If it does not then we may need to do a further operation to fine tune the first outcome.

Any problems?

Contact the eye clinic on 01223 216401 or 01223 216521

After 17:00 contact ward M5 on 01223 256336

We are smoke-free

Smoking is not allowed anywhere on the hospital campus. For advice and support in quitting, contact your GP or the free NHS stop smoking helpline on 0800 169 0 169.

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Contact us

Cambridge University Hospitals
NHS Foundation Trust
Hills Road, Cambridge

Telephone +44 (0)1223 245151