Bupivacaine injections for the treatment of age-related distance esotropia.

Purpose: Bupivacaine injection in the extraocular muscles is an emerging treatment for small angle strabismus. The aim of the study was to identify if it can be used as an effective alternative to surgery in patients with age-related distance esotropia (ARDE). Methods: All patients receiving either strabismus surgery or bupivacaine injections for ARDE at Aintree University Hospital in 2022-2024 were identified through surgical logbooks and electronic records. Electronic records were retrospectively analyzed to collect data on the age, visual acuity, surgical details, complications and pre- and post-operative horizontal deviation in primary gaze at distance and near fixation. Data were also collected on whether patients had any prior and subsequent treatment (prisms, surgery or bupivacaine) and whether they experienced diplopia at follow-up. Complete success was determined as there were no symptoms of diplopia and no need for further treatment. Results: Eight bupivacaine injections (BPX) and 11 lateral rectus resections (LRR) were performed on patients with ARDE. The average follow-up length was 44 and 143 days in the LRR and BPX group, respectively. The LRR group reduced the average horizontal distance deviation from 14 prism diopters (PD) (range 6-20) to 3.9 PD (range 0-8) (1d.p.). 7/11 (64%) of the procedures qualified as a complete success. The BPX group reduced the average horizontal distance deviation from 7.3 PD(1d.p.) (range 6-10) to 4.1 PD (range 1-15) (1d.p.). 5/8 (63%) of the procedures were a complete success. Conclusion: Bupivacaine injection can be used to successfully treat ARDE as an alternative or adjuvant to strabismus surgery.