Bupivacaine Injection without Electromyographic Guide for Correction of Residual Esotropia and Exotropia after Strabismus Surgery.

Purpose: To evaluate the effect of bupivacaine injection without electromyographic guide for correcting residual esotropia and exotropia after strabismus surgery. Methods: Thirty patients with residual esotropia or exotropia after strabismus surgery were included in the study. Three milliliters of bupivacaine 0.5% were injected into medial or lateral rectus muscle without electromyographic guide. Results: The mean pre-injection misalignments were 14.8 ± 3.4 (8-20) PD at distance and 14.7 ± 4.4 (6-25) PD at near. The 1 month post-injection alignment changes were 5.2 ± 2.6 (2-13) PD at distance and 6.5 ± 3.1 (2-18) PD at near. The 6 months post-injection alignment changes were 5.8 ± 2.6 (2-13) PD at distance and 7.0 ± 3.6 (2-18) PD at near. LogMAR of the worst eye had strong correlations with 6 months far alignment change (ρ = 0.39, p = .04), 6 months near alignment change (ρ = 0.41, p = .03), and 12 months near alignment change (ρ = 0.69, p = .01). Conclusion: The effect of bupivacaine injection without electromyographic guide for correcting residual esotropia or exotropia after strabismus surgery was between 2 and 18 PD, comparable with other studies on unoperated cases. The effect of bupivacaine may increase with decreasing visual acuity.