Downgaze restriction after placement of superior oblique tendon spacer for Brown syndrome.

Diplopia in the reading position developed in two patients with unilateral Brown syndrome after a 7-millimeter section of #240 silicone retinal band was sewn between the cut ends of the superior oblique tendon at tenotomy. In both cases, forced ductions were positive, indicating a restrictive downgaze deficit. Surgical exploration revealed adhesions that prevented the normal sliding of the superior oblique tendon beneath the superior rectus muscle. Forced ductions became normal and downgaze improved after removal of the silicone band. Secondary superior oblique muscle paresis was also evident at the time of reoperation, requiring recession of the contralateral inferior rectus muscle (cases 1 and 2) and recession of the ipsilateral inferior oblique muscle (case 1). A restrictive downgaze deficit and a paretic overcorrection must be recognized as possible complications of the superior oblique tendon silicone "expander" operation.