Repeated injections of botulinum toxin-A for epiphora in lacrimal drainage disorders: qualitative and quantitative assessment

Purpose To report the outcome of repeated botulinum toxin-A (BTA) injections in the lacrimal glands in patients with epiphora. Methods We performed retrospective chart review of patients who were injected with 2.5 units of BTA in the lacrimal gland. Epiphora and tear production were assessed by the Munk score and Schirmer-1 test, respectively, pre-injection and at 1 and 3 months post injection. Regarding repeated injections, the effects of the first were compared to those of the second and third injections. Results Forty-six eyes of 35 patients had an average of 2.3 injections per eye (range, 1–6). The mean Munk score significantly decreased from 3.72 to 1.87 at 1 month ( p < 0.001) and 2.21 at 3 months ( p < 0.001) after injection. The mean Schirmer-1 score also significantly decreased from 15.35 mm to 10.52 mm at 1 month ( p < 0.001) and 12.48 mm at 3 months ( p < 0.001) after injection. The mean reduction rates of Munk and Schirmer-1 scores after the second (66.1% and 29.8%, respectively) and the third injections (56.1% and 23.3%, respectively) were not significantly different from those after the first injection (63.3% and 26.1%, respectively) ( p > 0.05 for each comparison). There was a significant correlation between the difficulty in exposing the lacrimal gland for injection and the risk of complication ( p = 0.017). Conclusion BTA injection in the lacrimal gland showed favourable outcomes; repeated injections did not compromise efficacy. BTA injection can be safely repeated for epiphora, especially in patients whose lacrimal gland can be easily exposed.