Treatment of Intermittent Exotropia of the Convergence Insufficiency Type with Bupivacaine 0.75%: 5-Year Experience and Outcomes.

INTRODUCTION: Bupivicaine has been shown to stimulate ocular muscle structure and length after injection into ocular muscles. Bupivicaine 0.75% has been utilized in the treatment of strabismus to alter ocular alignment by strengthening an ocular muscle. This study is designed to report 5-year follow-up outcomes after bupivicaine injection.

METHODS: A retrospective chart review of all bupivicaine treated strabismus patients with symptomatic intermittent exotropia of the convergence insufficiency type (CIXT) from 2009 through 2016. Success was measured as resolution of symptoms (diplopia, difficulty reading, intermittent blurry vision, and headaches) with or without prisms (<5Δ ).

RESULTS: At a 5-year outcome, success rate was 80%. Mean near deviation changed from 10.6Δ to 3.8Δ . Outcome was the same at 6 months (n = 124) vs 5 years (n = 30) unless a new onset strabismus occurred (TAED, CN palsy, CVA). In older patients, a large number (10%) of patients developed new onset strabismus. There were no moderate or severe complications after injection. There appears to be a predictable dose response curve.

DISCUSSION: At 6 months outcome, treatment of CIXT with bupivacaine (91%) has a similar rate of success as traditional resection (92%). Older patients need to be informed of the incidence of new onset strabismus causing recurrence of symptoms (10%).

CONCLUSION: At 5 years outcome, bupivicaine 0.75% offers a simple alternative therapy for CIXT type strabismus patients. There is little risk and less expense than traditional resection surgery without the overcorrections.