Successful outcome in synergistic divergence after unilateral lateral rectus recession and medial rectus resection

Synergistic divergence, sometimes identified as type IV Duane syndrome, belongs to a group of congenital disorders characterized by aberrant extraocular muscle innervation. In synergistic divergence, there is paradoxical abduction of both eyes on attempted gaze to one side. There is no consensus on surgical management of this rare disorder. We present the case of a 23-year-old man who underwent strabismus surgery for a large right exotropia and compensatory left head turn, which he had adopted to maintain single binocular vision from at least 4 months of age, when he first presented with strabismus. The left head turn was corrected with a 14 mm right lateral rectus recession and a 10 mm right medial rectus resection. Although surgical correction by means of lateral rectus periosteal fixation or extirpation has been reported previously, this case supports large recession and resection as an alternative for surgical treatment of synergistic divergence.