Exploratory Prospective Randomized Controlled Study to Evaluate a Modified Botulinum Toxin Injection Pattern for Treatment of Benign Essential Blepharospasm.

[PURPOSE] This study aimed to explore trends in duration of effect, effectiveness of spasm control, and complication rates, as well as assess feasibility between an established versus a modified pretarsal botulinum toxin (Botox) injection pattern for treatment of benign essential blepharospasm (BEB).

[METHODS] In this exploratory randomized controlled trial, patients diagnosed with BEB (excluding those with prior myectomy) were randomized to receive either an established or modified pretarsal Botox injection pattern on each side of the face. A total of 50 or 60 units of onabotulinumtoxinA (Allergan, Irvine, CA, USA) were administered. Primary outcomes included the duration of effect, spasm control, and complication rates, assessed using a 10-point Likert scale immediately following initial injection and at a three-month follow-up post injection. Statistical analysis was performed using paired t-tests (α<0.05).

[RESULTS] Eight female patients (mean age 71.0±9.53 years) were followed for 110±26.9 days. The trends of the results suggest that the modified pattern has a longer mean duration of effect (82.9±38.4 vs. 63.8±36.2 days, p=0.13) and improved spasm control (7.38±2.13 vs. 6.63±2.13, p=0.41). Spasm severity and pain levels during injection were similar between patterns. Complications were comparable, with reports of dry eye, tearing, and ptosis in both groups. Statistical significance was not reached due to small sample size as this was an exploratory study to inform future research.  Conclusion: The modified pretarsal botulinum toxin injection pattern demonstrates potential as an alternative approach for treating BEB, with observed trends toward improved duration and effectiveness of spasm control, without added complications. Further research with larger sample sizes is needed to confirm these preliminary findings.