The superior oblique tendon can be functionally divided into the anterior one-third, which is responsible for intorsion, and the posterior two-thirds, which is responsible for depression and abduction (Fig. 18.1). Superior oblique tightening procedures are based on this physiologic division and either tighten the whole tendon (i.e., full-tendon tuck) or tighten the anterior tendon fibers (i.e., the Harada-Ito procedure).