Childhood strabismus is the loss of the eyes’ parallelism. Deviation can be inward (convergent strabismus), outward (divergent strabismus) or vertical (upward and downward). The strabismus origin is multifunctional and many of the trigger factors are not yet known. What is certain is that around 97% of cases are due to a functional cause, that is to say, without any organic brain lesion. The rest of them arise from neurologic, metabolic, vascular or malformative diseases of the central nervous system. This pathology can appear at any age. In half of the cases, childhood strabismus usually starts before the age of one. Late strabismus, over the age of three, is normally due to uncorrected refractive errors (above all hypermetropia). Once it is established, strabismus doesn’t disappear spontaneously.

Congenital divergent strabismus

Congenital divergent strabismus

The most apparent symptom is eye deviation which is the warning sign that makes parents consult a specialist in ophthalmology. Nevertheless, deviation entails a series of “non-visible” consequences.

  • Amblyopia or lazy eye: the deviated eye is suppressed in order to avoid double vision
  • Loss of binocular vision and, in consequence, of stereopsis

The earliest strabismus appears, the most serious these disorders are.


Strabismus can’t be prevented. Nonetheless, early detection is extremely important to treat it as soon as possible in order to reverse the above-mentioned consequences. In this sense, ophthalmologists get a huge help from paediatricians who have a more continuous contact with children, who thoroughly know about this pathology and quickly refer children to the specialist. As a general rule, every child (even though parents don’t observe anything wrong) should be explored by an ophthalmologist at the age of three. Those with prior family history of strabismus or lazy eye, should undergo this examination even earlier.

Convergent Strabismus



A standard treatment of strabismus doesn’t exist although we can establish a therapeutic algorithm. First of all, a refractive defect must be ruled out and, should it exist, the prescription of glasses for vision correction would be necessary. If there is amblyopy, it must be treated by means of the different available methods according to its seriousness (occlusion, penalisation, etc.). Finally, a surgical operation will be carried out in all those cases in which deviation causes an obvious aesthetic defect. Strabismus treatment is long and requires being closely surveilled for many years. Unfortunately, surgery must be repeated in 30% of cases. The reason of this high rate of failures is that the brain of a child who suffers from childhood strabismus not always accepts the position induced by surgery as the right one, and tends to drive the eye towards its initial position. If you wish to know more about strabismus, please click here.