Children's squint

What does that word mean?

Atropine treatment for Amblyopia (lazy eye)

The medical term is…


But it is often known as…


A squint is when one eye turns inwards, outwards or upwards, while the other eye looks straight ahead. It often starts in childhood, sometimes within weeks of being born.

What does that word mean?

The word strabismus comes from the Greek word streblos meaning "turned" or "twisted

How you see the world

Because you are not using both of your eyes together you might find it difficult to see clearly, you might not see things in full 3-D or you might notice double vision. If the squint started when you were a young child, you might not notice anything wrong.

How the world sees you

In large squints, it can be obvious that one eye does not look straight. Small squints might not be noticeable to other people. Some people with a squint look at things with one eye closed, or turn their head to one side.

Why did I get it?

There are different types of squint, and the cause is not always known, although it can run in the family. A baby can be born with the condition. If you have a glasses prescription, trying hard to focus can sometimes cause one eye to turn. Occasionally, squint can occur due to muscle or nerve problems, or because the eye has something else wrong which affects the vision.

The left image is an in-turning (convergent)squint and the right image is an out-turning (divergent)squint

Different types

The types of squint are:

  • Convergent squint - the affected eye looks inwards
  • Divergent squint - the affected eye looks outwards towards the corner of the eye
  • Vertical squint - the eye looks up or down (although this is unusual)

The squint might be there all the time or only some of the time.

 Is it common?

Strabismus affects 5-8% of children (1-2 in every 30).

How can the doctor tell?

Tests are usually carried out by an orthoptist who is trained to identify conditions such as strabismus. The orthoptist might shine a light at you and see if the reflection of the light is in the same place in both eyes or not. They also cover each of your eyes in turn and see if one eye has to straighten up to see things.

Getting it sorted

People with a squint should be tested in the eye clinic as soon as possible after it is detected, especially young children where the sight in the affected eye may gradually get worse. Some squints might get better as you get older and not all squints need treatment.

There are several types of treatment:

  • If you have a glasses prescription, glasses might help the sight or the squint
  • You might need to wear a patch over your good eye, to encourage the eye with the squint to work harder and see better
  • Some squints can be treated with eye exercises
  • Some squints need surgery
Surgery for a squint involves moving the muscles attached to the outside of the eye to a new position. It might be necessary to operate on both eyes in order to 'balance' them, even if the squint is only in one eye. Some squints need more than one operation.

When the going gets tough

A complication that can develop if a squint is untreated is amblyopia (lazy eye). Vision in the squinting eye gradually gets worse because the brain starts to ignore the weaker message being sent from that eye. Patching the good eye can make the vision in the bad one better, but it works less well after the age of 7-8 years and by then it is often not possible to correct the vision.

Interact with the animated eye and learn more about different kinds of squint

  • Strabismus is common: about one in 30 children have it
  • Not all squints need treatment
  • Patching helps the sight not the look of the squint

Moorfields Eye Hospital NHS Foundation Trust

City Road, London EC1V 2PD

Phone: 020 7253 3411

Moorfields Direct Telephone Helpline

Phone: 020 7566 2345

Monday to Friday 09.00 to 16.30 for further information and advice.


Article approved by Moorfields Children’s Information Group

Last Reviewed: May 2010 Date for review: May 2012


Last updated: 20th November 2017