A squint, also called strabismus, is where the eyes point in different directions. It's particularly common in young children, but can occur at any age.

One of the eyes may turn in, out, up or down while the other eye looks ahead.

This may happen all the time or it may come and go.

Treatment is usually recommended to correct a squint, as it's unlikely to get better on its own and it could cause further problems if not treated early on.

When to get medical advice

Get advice if:

  • your child has a squint all the time
  • your child is older than three months and has a squint that comes and goes – in babies younger than this, squints that come and go are common and aren't usually a cause for concern
  • you have any concerns about your child's vision – signs of a problem can include regularly turning their head to one side or keeping one eye closed when looking at things
  • you develop a squint or double vision later in life

Your GP, health visitor or local opticians service can refer you to an eye specialist for some simple tests and treatment if necessary.

Treatments and surgery for a squint

The main treatments for a squint are:

  • Glasses – these can help if a squint is caused by a problem with your child's eyesight, such as long-sightedness.
  • Eye exercises – special exercises for the muscles that control eye movement may sometimes help the eyes work together better.
  • Surgery – this involves moving the muscles that control eye movement so the eyes line up correctly. It may be recommended if glasses aren't fully effective on their own. Read more about squint surgery below.
  • Injections into the eye muscles – these weaken the eye muscles, which can help the eyes line up better. But the effect usually lasts less than three months.

If your child has a lazy eye as a result of their squint (read about possible further problems below), it may need to be treated first.

Treatment for a lazy eye usually involves wearing a patch over the unaffected eye to help improve vision in the affected eye.

Problems that can occur if a squint isn't treated

It's important not to ignore a squint that happens all the time or occurs after three months of age.

It could lead to further problems if left untreated, such as:

  • persistent blurred or double vision
  • a lazy eye – where the brain starts to ignore signals coming from the affected eye, so your child doesn't develop normal eyesight
  • embarrassment or low self-esteem

Surgery can help improve the alignment of the eyes even if a squint has been left untreated for a long time, but any vision problems may be permanent if they're not treated at a young age.

Causes of squints

The exact cause of a squint isn't always known.

Some people are born with them and others develop them later in life. Sometimes they run in families.

In children, they're often caused by the eye attempting to overcome a vision problem, such as:

Rarer causes of a squint include:

  • certain infections, such as measles
  • some genetic conditions or syndromes, such as Down's syndrome
  • developmental delays
  • cerebral palsy
  • other problems with the brain or nerves

A squint can also sometimes be a symptom of a rare type of childhood eye cancer called retinoblastoma. Take your child to see your GP if they have a squint to rule out this condition.


Surgery to correct a squint may be recommended if other treatments aren't suitable or don't help.

The operation involves moving the muscles that control eye movement so that the eyes line up better.

Preparing for squint surgery

Before surgery:

  • you'll attend a pre-operative assessment – some simple tests will be done to check that you can have the operation and you'll have the chance to ask any questions about it
  • you'll be told when to come into hospital for the procedure and when you should stop eating and drinking beforehand
  • you'll need to sort out how you'll be getting home – you can usually go home the same day, ideally with a friend or family member to escort you (as you may be sleepy); you won't be able to drive for at least a day or two if you've had surgery

What happens during squint surgery

Squint surgery is done under general anaesthetic (where you're asleep) and usually takes less than an hour. You or your child can usually go home the same day.

If your child is having surgery, you'll be able to accompany them into the operating room and stay with them until they've been given the anaesthetic.

During the procedure:

  • the eye is held open using an instrument called a lid speculum – sometimes it may be necessary to operate on both eyes to get the alignment right
  • the surgeon detaches part of the muscle connected to the eye and moves it into a new position so that the eyes point in the same direction
  • the muscles are fixed in their new position with dissolvable stitches – these are hidden behind the eye so you won't be able to see them afterwards

Sometimes, in adults and teenagers, further adjustments to your eye muscles may be made when you've woken up after the operation. Local anaesthetic eye drops are used to numb your eyes for this.

After squint surgery

Following the operation, a pad may be put over the treated eye. This is usually removed the next day, or sometimes before you go home.

The eye is likely to be sore for at least a few days. You may be given painkillers to reduce discomfort and some eye drops to help with healing.

You may experience some of the following side effects:

  • eye pain – this tends to last at least a few days and often feels like grit or sand in the eye; taking simple painkillers such as paracetamol can help, although children under 16 shouldn't be given aspirin
  • red eyes – this can last for a couple of months; you may also have blood in your tears for a day or two
  • itchy eyes – this is caused by the stitches and it may last a few weeks until they dissolve; try not to rub your eyes
  • double vision – this usually passes after a week or so, but can last longer

You'll be asked to attend follow-up visits with an eye specialist after surgery. Contact them, the hospital or your GP if you have any severe or lasting side effects from surgery.

Returning to normal activities

It can take several weeks to fully recover from squint surgery.

Your doctor or care team can give you specific advice about when you can return to your normal activities, but generally speaking:

  • you can read or watch TV and carry out other daily activities as soon as you feel able to
  • you can return to work or school after about a week
  • don't drive for at least a day or two (as the anaesthetic may not have fully worn off), or for longer if you have double vision
  • try not to get any soap or shampoo in the eye when washing
  • most people return to exercise and sport after about a week, although you may asked to avoid swimming and contact sports (such as rugby) for two to four weeks
  • don't use make-up close to the eyes for four weeks
  • your child shouldn't play in sand or use face paint for two weeks

If you wore glasses before surgery, you'll probably still need to wear them. But don't wear contact lenses until you're told it's safe to do so.

Risks of squint surgery

As with any kind of operation, there's a risk of complications after surgery to fix a squint. Serious complications are estimated to occur in 2 to 3 in every 1,000 procedures.

Risks include:

  • further surgery being needed to fully correct the squint – this is quite common, particularly if the squint is severe
  • permanent double vision – this may require special glasses to correct your vision (read more about how double vision is treated)
  • an infection, abscess (build-up of pus) or cyst (build-up of fluid) around the eye – this may require treatment with antibiotics and/or a procedure to drain the pus or fluid
  • the eye muscles slipping out of position – further surgery may be needed to correct this
  • a small hole being made in the eye as the eye muscles are stitched in place – this may require antibiotics to prevent infection and a procedure to close the hole
  • loss of vision – this is very rare

Speak to your surgeon about the risks of surgery before the operation.

The information on this page has been adapted by NHS Wales from original content supplied by NHS UK NHS website nhs.uk
Last Updated: 16/12/2021 15:41:50