Faden procedure

The Faden procedure is a strabismus operation that sutures a rectus muscle to the sclera behind the equator, creating a new insertion posterior to the anatomical one.¹ The word faden is German for thread or suture, and the operation is also called a posterior fixation suture or retroequatorial myopexy.¹

The Faden procedure weakens a rectus muscle selectively in its own field of action without disturbing the balance between agonist and antagonist in other positions of gaze.^1,2 The classic explanation is mechanical.¹ Fixing the muscle behind the equator shortens its lever arm on the globe, so the muscle needs more force to rotate the eye the same amount.¹ The extra innervation also flows to the yoke muscle of the fellow eye, as Hering's law requires.¹

The operation is most effective on the medial rectus, less effective on the vertical recti and least effective on the lateral rectus.¹ On the medial rectus, the Faden procedure reduces convergence in convergence excess esotropia, and on the superior rectus it treats dissociated vertical deviation.² A posterior fixation suture on the yoke muscle can also restore single vision in a mild paresis that causes diplopia only in peripheral gaze.¹