A strabismus is a misalignment of the eyes so that only one eye is pointing at what the child is looking at. Misalignments can be horizontal or vertical and constant or intermittent. Different squints are treated in different ways. A very common form is a convergent squint when the eye turns towards the nose. The majority of children with convergent strabismus are longsighted – they have to actively focus the eye in order to see clearly. Normal eyes only need to focus for near vision and are completely relaxed when looking in the distance. When the child is longsighted they may actively focus until one eye can see clearly but the extra focusing will cause the eye to turn in. If one eye is more longsighted than the other it will remain blurred and this will result in lazy eye or amblyopia as the brain processes vision from the better eye and neglects to use the worse eye. When a longsighted child with a convergent squint is given their glasses they can see clearly with no active focusing for distance and only the normal amount of focusing for near. In some children the glasses completely control the squint but in others squint surgery is required. In general it is better to fully treat amblyopia (lazy eye) before carrying out squint surgery.

When children need strabismus surgery it is carried out under general (full) anaesthetic. There are 6 muscles that move each eye and the function of any of these can be changed by moving their position on the eye or weakening or tightening the muscle. Your surgeon will be able to advise you about which muscles will be operated on and why. In some cases surgery on just one eye is best and in other cases operating on muscles in both eyes is advisable to get the best results.