Family doctor

Understanding squints

A squint is present when the two eyes are not looking in the same direction. It may be apparent all the time or only when a patient is tired, unwell or focussing on a close object. Usually the eye turns in but it may turn out and a squint can be seen to alternate between the eyes.

Babies often have the appearance of a squint due to a wide bridge of the nose and this appearance is lost as the face develops. The child with a true squint will not grow out of it, so all children suspected of a squint must be seen by an eye specialist.

Squints can also be seen in adults as a long standing problem or following a nerve palsy.

What causes the squint?

Squints may occur in families and can be seen under the age of 12 months but most commonly around the age of two years. In early onset squints the child has a poor ability to use the two eyes together (binocular vision) and in later onset squints, binocular vision is quickly lost.

Children may be long sighted and the effect of focusing leads to the squint. Glasses can correct this problem.

Very occasionally a child will develop a squint because an eye is abnormal and has defective sight. The earlier this is detected the sooner treatment can be started.

If a child squints with one eye, the vision in that eye will become lazy as the brain ignores information from the deviating eye.

What are the effects of a squint?

1. A child may develop a lazy eye which if not corrected will lead to poor sight in that eye
2. A child will lose binocular vision (ability to use the two eyes together)
3. A squint may spoil one's appearance
4. In adults the main symptom is often double vision

When should treatment start?

Children suspected of a squint should be seen without delay by an eye specialist. No child is too young to be seen. In adults a squint from a nerve palsy may recover on its own and treatment is therefore only undertaken once the squint has stabilised.

What is the treatment?

Glasses will be prescribed if there is a focussing error particularly in long sightedness.

If a child squints with one eye only, then this eye will become lazy. The other eye is patched to achieve alternation such that the child can switch from one eye to the other allowing vision to develop equally.

If the appearance of a squint is obvious, then surgery is carried out to move the eye muscles and thereby straighten the eye. In some cases surgery is performed early in an effort to achieve binocular single vision. This surgery is done as a day stay under general anaesthesia usually between the ages of one and three in children or at any convenient time in adults.