Variant types of Duane retraction syndrome: synergistic divergences and convergences

To present the clinical features of 4 patients with Duane retraction syndrome characterized by synergistic divergence or convergence, abnormal vertical movements, and accessory fibrotic bands.

The medical records of 4 patients were reviewed retrospectively for the following clinical manifestations: visual acuity, refraction, ocular alignments, ocular motility, head position, magnetic resonance imaging, surgical techniques, and outcomes.

All 4 cases were diagnosed as variants of Duane retraction syndrome. Two cases (cases 1 and 2) had synergistic divergence with unilateral adduction deficit, and 2 (cases 3 and 4) had synergistic convergence with bilateral abduction deficit. Case 2 manifested abnormal vertical movements of the right eye, which goes down with adduction of the left eye and goes up oppositely with abduction of left eye. Accessory fibrotic bands were detected beside the medial rectus muscle of both eyes in case 3. Synergistic convergence in case 4 occurred only after the first strabismus surgery. Weakening of the misinnervated horizontal rectus muscle improved ocular alignment and head position in cases 1, 3, and 4.

Synergistic divergence and convergence are extremely rare and may present with a great diversity of clinical features. A good outcome is very difficult to achieve; however, weakening of the misinnervated horizontal rectus muscle was therapeutic in these patients.