Lazy eye

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What is a lazy eye?

A lazy eye is more commonly known as a squint, and it is a condition in which one eye turns slightly in or out relative to the other eye. It is extremely common among babies, but will usually disappear by the time they are six months of age.

The medical term for squint is strabismus. The squint may be convergent, in which one eye is directed too far inwards or divergent, in which one eye is directed too far outwards.

How does it occur?

In normal eyes, the retinas receive images from slightly different angles, and these fuse together to give the brain a single composite picture to interpret. If there is a squint in the eyes, the images cannot fuse and the brain receives two different images or ‘messages.’ Because the brain cannot interpret these two different images at once, it rejects one and interprets the other.

If the brain continues to interpret images from only one eye, this will eventually lead to a reduced sharpness of visions (amblyopia).

So a lazy eye is serious?

Yes, any child with a lazy eye or squint over the age of six months should be referred for further examination. If left untreated, this condition can lead to gradual reduction in the sharpness of vision through lack of use of the ‘lazy’ eye.

Squints which develop for the first time in adults may be the result of one of a number of disorders affecting the brain, the nerves controlling the eye muscles or the eye muscles themselves. Squints in adults cause double vision.

How is it treated?

The old tried and trusted method of putting a ‘patch’ or a pad of cotton wool over the good eye is still the best method of treating a squint. By covering the good eye, the brain is forced to accept images from the lazy eye. Over a period of time the child will learn to use his lazy eye and to focus perfectly on objects until the wearing of the eye patch is no longer necessary.

Does an eye patch always solve the problem?

In the vast majority of cases, an eye patch will solve the problem of a lazy eye. When the child is older, he/she will probably also be given a simple set of exercises to strengthen his eye muscles.

In cases where severe squinting persists, even after the wearing of an eye patch, a simple surgical procedure can be carried out to adjust the lengths of the eye muscles. This involves a short hospital stay and is generally a very successful operation with no long-term complications.

Squints which occur for the first time in adults always require medical investigation. Treatment will depend on the cause identified.

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