Superior oblique muscle paresis after sub-Tenon's anesthesia for cataract surgery.

A 68-year-old man developed strabismus after having sub-Tenon's anesthesia for cataract extraction and intraocular lens implantation. An ipsilateral hypertropia with superior oblique muscle paresis developed in the operated eye. The hypertropia appeared 1 day after surgery and resolved 1 month later. Although sub-Tenon's anesthesia is considered safer than other methods of local anesthesia, strabismus may occur.