Fig. 9 Patient with a chronic left sixth nerve palsy. Top row. Preoperatively, note significant lack of abduction of the left eye. Middle row. One month postoperatively the patient has a significant paralysis of his left medial rectus muscle secondary to the botulinum A toxin injection. Note the amount of abduction. Bottom row. Six months postoperatively, the patient had 70-degree of single binocular vision and 3 degrees of abduction. (McManaway JW, Buckley EG, Brodsky MC: Vertical rectus muscle transposition with intraoperative botulinum injection for treatment of chronic sixth nerve palsy. Graefes Arch Clin Exp Ophthalmol 228:403, 1990)