SQUINTS

A squint or strabismus is present when the two eyes are not looking in the same direction. It may be apparent all the time or only when the person is tired, unwell or focusing on a near or distant object. The eye may turn in or out, or one eye may sit higher than the other.

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. However, a 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.

WHAT CAUSES THE SQUINT?

Squints may occur in families and may arise in the first few months of life. However, they may also appear in older children. Some children have a weak ability to use the eyes together, and a squint can develop. If a squint is present, the misalignment means that the eyes will lose the ability to work together and achieve 3-D vision (binocular vision).

Children may be farsighted and have a focusing problem, in which case the effort of focusing to see clearly may lead to a squint. Glasses alone may correct this problem.

Very occasionally a child may develop a squint because there is a problem with the eye and it has defective sight. The earlier this is detected the sooner treatment can be started.

If a child squints with one eye, then the vision in that eye will become lazy (amblyopic) as the brain ignores information from the squinting eye.

WHAT ARE THE EFFECTS OF A SQUINT?

• a child may develop a lazy eye (amblyopia) which if not treated will lead to long term poor sight in that eye
• a child will lose binocular vision
• a squint may spoil one’s appearance
• in adults the main symptom is often double vision.

WHEN SHOULD TREATMENT START?

Children suspected of having a squint should be seen without delay by an eye specialist. No child is too young to be seen. In adults a squint from 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 focusing error, particularly with farsightedness. If a child squints with one eye, then the eye will become lazy. By patching the other eye, the child has to use the lazy eye. This will assist in improving the vision in the lazy eye to a level comparable with the good eye. The child will then be able to use either eye to see and the squint will switch from one eye to the other (alternation), which is the aim of the treatment. 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 vision.

In children, surgery is usually performed between the ages of six months and four years, and in adults it may be performed at any convenient time once the squint has stabilised. Squint surgery is performed as a day stay procedure usually under general anaesthesia.