Vertical Strabismus Associated With Plagiocephaly

Thirty-three patients with plagiocephaly due to unilateral coronal synostosis have been studied because of a high incidence of vertical strabismus. Twenty-seven of the 33 patients were found to have an ipsilateral hypertropia. In two patients the hypertropia disappeared after early neurosurgical correction of the coronal synostosis, but in most patients the hypertropia persisted, mimicking a fourth cranial nerve palsy with overaction of the inferior oblique muscle and a head tilt to the opposite shoulder. We think the vertical muscle imbalance is due to structural abnormalities of the orbit induced by the cranial synostosis. Appropriate strabismus surgery reduced the ocular deviation in five patients.