Length-tension diagrams of medial rectus muscles after Cüppers' fadenoperation. Surgical assessment of the reversibility of posterior fixation sutures.

Length-tension diagrams of 6 medial rectus muscles, previously submitted to a posterior fixation suture (fadenoperation), were compared to 6 unoperated medial rectus muscles. Both sets of patients presented a nonaccommodative convergence excess esotropia, uncontrolled by conservative treatments (full refraction and progressive addition lenses or bifocals). No changes were found in primary length or spring constant in the muscles operated on with a bridge suture technique (Castiella), in contrast with a marked stiffening appearing in the muscles operated on following Cüppers' original technique.