Fadenoperation for the management of complicated incomitant vertical strabismus.

We reviewed retrospectively the records of 17 patients with incomitant vertical diplopia secondary to an underacting inferior rectus muscle who had been treated by surgically weakening the contralateral inferior rectus muscle with a posterior fixation suture (fadenoperation). This was the sole procedure in four patients with blowout fractures and in two patients with restriction secondary to scleral buckling procedures. It was combined with horizontal or vertical muscle surgery in 11 patients. The procedure was particularly useful in preventing diplopia on downgaze after excessive weakening of a tight inferior rectus muscle in seven patients with thyroid ophthalmopathy. In three patients it was used in anticipation of an iatrogenic incomitancy in downgaze secondary to a large recession of a tight inferior rectus muscle. All patients were markedly improved after surgery and no complications were encountered.