Surgical correction of synergistic divergence strabismus. A report of three cases.

Background and purpose: To review and explain some of the characteristics of synergistic divergence and compare the surgical effect on each of those characteristics.

Methods of study: Three patients demonstrating findings characteristic of synergistic divergence, two bilateral and one unilateral, are reported. Surgery consisted of denervation extirpation of the lateral rectus muscle along with resection of the medial rectus muscle of the affected eye or supramaximal recession of the lateral rectus muscle and resection of the antagonist medial rectus muscle of the affected eye.

Results: The simultaneous abduction and the abnormal head posture responded well to surgery. The exotropia was reduced. The deficient adduction, the total absence of active abduction and the infraduction of the synkinetically abducting eye remained unchanged.

Conclusions: Synergistic divergence is a severe exotropic form of Duane's Syndrome where the feature of simultaneous abduction is the most striking. To date, no surgical procedure leads to satisfactory results on all the characteristics of synergistic divergence. Although some important features can be satisfactorily improved, some others do not respond to current surgical techniques.