True transposition procedures.

Three patients with large-angle strabismus and irreversible amblyopia in a previously-operated eye underwent a true transposition procedure in which a segment of resected extraocular muscle was used to lengthen its antagonist. Postoperative results were satisfactory and stable during follow-up of 9 to 14 months. Four prism diopters of deviation were corrected per millimeter of "alteration" (mm resection plus mm lengthening plus mm recession minus mm advancement). True transposition procedures can permit surgeons to capture large strabismus deviations with two-muscle surgery on one eye, appear safe and predictable, and offer an option in those patients who refuse adjustable suture techniques.