Persistent Diplopia after Local Anesthesia

ABSTRACT

PURPOSE: To determine causative factors of persistent diplopia after local anesthesia for ophthalmic surgery. METHODS: Prism and alternate cover test in the diagnostic positions of gaze and ductions/versions testing were performed in 26 patients with persistent diplopia six months after local anesthesia. Lancaster test, Bielshowsky head tilt test, double Maddox rod test, funduscopic examination for torsion, forced duction test, force generation test, tensilon test, thyroid function test, and/or orbit CT were done when necessary. RESULTS: Most of the patients (24 patients, 92%) did not have diplopia before local anesthesia. Of the thirteen patients with strabismus resulting from trauma to extraocular muscles, eleven patients showed vertical rectus overaction (10 superior recti, 1 inferior rectus) and two patients, mild vertical rectus underaction. Eight patients were presumed to have sensory deviation. In the remaining patients, one patient had childhood esotropia and another, old superior oblique palsy. Three patients showed a small vertical deviation without any specific cause. CONCLUSIONS: Fifty percent of diplopia was related with the surgical trauma to extraocular muscles, in which overactions (42%) were more common than underactions (8%). Thirty-five percent of the patients were presumed to have sensory deviation, which suggested the importance of preoperative examination for strabismus as well as the explanation about the risk of postoperative diplopia before surgery.