ABSTRACT
PURPOSE: This study aims to evaluate the effect of bupivacaine injection at 1.5% combined with recession of the antagonist rectus muscle to treat sensory strabismus in adult patients. METHODS: Nine patients with a horizontal deviation, visual acuity of <20/60 in the worst-seeing eye, and no previous strabismus surgery were selected. Patients with vertical strabismus were excluded. Lateral rectus (LR) recession was performed in patients with exotropia and medial rectus (MR) recession in patients with esotropia according to Park's Table, as modified by Wright. Bupivacaine 1.5 mL at 1.5% was injected in the antagonist of the recessed muscle. The patients were evaluated after 1, 7, 30, 60, 90, and 180 days of the procedure. Successful motor alignment was defined as within 10 prism diopters (PD) of orthophoria. Dose-response was considered as the total amount of correction, divided by recession performed in millimeters, associated with bupivacaine injection in the antagonist muscle. RESULTS: Of the patients, 44% (4/9) had a successful motor alignment. The mean correction for exotropia (n = 5) with a preoperative horizontal deviation of 50 ± 6.12 PD was 23 ± 14.4 PD with a dose-response of 2.6 PD/mm. For esotropia (n = 4), the mean correction of 21.25 ± 4.8 PD was achieved with a preoperative deviation of 28.7 ± 14.9 PD with a final dose-response of 5 PD/mm. All unsuccessful patients had a preoperative deviation of ≥45 PD. CONCLUSION: Bupivacaine injection in the antagonist of a recessed extraocular muscle (EOM) appears to add an effect to the standard dose-response of a muscle recession. For patients with esotropia (<25 PD), a single MR recession combined with bupivacaine in the LR can produce a successful motor alignment. For patients with large horizontal strabismus (>45 PD), larger bupivacaine doses (volume and concentration) combined to larger recessions may be needed.
