Squint in children -delay in treatment can cause permanent impairment of vision

Squint in children is a common problem. In order to understand the consequences of delayed treatment it is necessary to learn something about normal vision.

For more details about the structure of the eye visit healthy eyes.

When we look at an object it forms an image on the retina of each eye. The optic nerve from each eye carries the impulse to the brain which interprets the electrical impulses from both the optic nerves as one object.

For proper binocular vision the two eyes should be properly aligned so that the images fall on the corresponding area of the retina. Strabismus or squint is a condition in which the two eyes are not properly aligned.

Squint can be either paralytic (due to paralysis of muscles controlling the movements of the eye ball) or non paralytic (just imbalance between the various muscles). The latter is more common.

Depending on the type of abnormal deviation squint can be classified as estropia exotropia, hypertropia and hypotropia.

In esotropia the abnormal eye deviates towards the nose (inwards). In exotropia the deviation is away from the nose (outwards). In hypertropia the eye turns upwards. In hypotropia the eye turns downwards.

Esotropia (convergent squint) The right eye is turned towards the nose.

Exotropia (divergent squint) The left eye is turned away from the nose.

Vertical squint The right eye is turned upwards.

Some degree of squint is normal is young infants up to the age of 6 months. But after six months the eyes should be properly aligned.

Refractive errors can cause squint.

Complications: When an eye is not properly aligned the image of any object from that eye is blurred. Hence the brain begins to ignore that image because the images from the two eyes cannot be fused leading to double vision (the child sees two images of one object).

The deviating eye will not focus properly on an object. Due to lack of stimulation the vision in that eye will gradually diminish. This condition is called amblyopia.

If not treated early the vision will be permanently impaired. Hence it is very important to treat squint in children early. Amblyopia can also be due to other causes and then may result in squint.

Diagnosis: If a beam of light is focused on the eyes with the child looking straight the light reflex on the two eyes will be centered if the eyes are properly aligned. If there is squint the reflex in the affected eye will be off center.

Cover test: The child is asked to look at an object. When the normally focusing eye is covered the deviating eye will move to focus on the object. If there is no squint there will be no corrective movement.

Treatment of squint in children: Any refractive error should be promptly corrected. The normal eye may be covered to encourage the deviating eye to focus so that vision does not diminish. Special exercises are advised to improve alignment. Surgery may have to be considered if other measures fail.

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