Squint or turn, A.K.A. strabismus is present where there is an obvious misalignment of the eyes either all the time (constant) or occasionally (intermittent). The deviating eye may turn in (convergent) or out (divergent).

What causes a strabismus?

One of the most common causes of a convergent strabismus is uncorrected long-sightedness. Other causes can be problems with coordinating the eye muscles due to damage e.g. sometimes following a difficult birth or forceps delivery, or, very rarely, by an eye disease or another health problem.

What are the symptoms?

One eye will turn in or out either constantly or intermittently. Mothers are the best at suspecting a problem, and sometimes more than one visit to the optician is necessary before the turn can be detected, especially if it is intermittent.

What can be done to help a strabismus?

Corrective spectacles are needed to focus the retinal image properly and enable clear vision and so the first step is to ensure that they are worn where necessary. All children suspected of having a turn will have their eyes examined using drops which temporarily stop the eye muscles from focusing properly so the full extent of the visual problem (if any) can be diagnosed. If there is an uncorrected visual problem, the first step is constant wear of the corrective spectacles. In many cases this is sufficient to straighten the eyes and stop the turn and in others it will decrease the angle of the turn. It is essential that turns are treated from as early an age as possible and definitely pre-school to try to help prevent a lazy eye, which is caused by stunted visual development in the deviating eye. In children whose strabismus does not respond to spectacle correction, referral to an opthalmologist through the GP is the next step. The child will be assessed by an orthoptist (a specialist in eye co-ordination) for treatment, which may include exercises and patching. In non-responsive cases, the ophthalmologist may decide that surgery is indicated.

Can I do anything to stop a strabismus (turn) getting worse?

The child needs to wear any corrective spectacles all the time to encourage normal visual development. If the orthoptist recommends exercises of patching, they need to be done religiously. There is a short period of time when the visual system will respond and the treatment regime needs to be aggressive at this stage because once the child is 5 or 6 years of age, the visual system starts to become less responsive and less improvement will occur.