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.