Effect of botulinum toxin type a on tear production after treatment of lateral canthal rhytids.

PURPOSE

To evaluate the incidence of temporary dry eye and the effects on lacrimal gland tear production after treatment of lateral canthal rhytids with botulinum toxin type A injections.

METHODS

Twenty-six crow's feet areas were injected with botulinum toxin type A in 13 women with an age range of 31 to 58 years. A total of 10 units of botulinum toxin was injected per side, with two separate injections. Schirmer 1 testing was performed before and at 1 week, 1 month, and 4 months after the injections in all patients. The test was repeated at 6 months and 9 months for the patients whose Schirmer test results were not back to baseline at the 4-month follow-up. Statistical significance was evaluated with paired t test analysis.

RESULTS

Overall, no statistical difference was found in Schirmer test results from baseline at 1 week (p = 0.23), 1 month (p = 0.32), or 4 months (p = 0.30) after injection. Five eyes of three patients had a significant decrease in Schirmer test results from baseline at 1 week and 1 month after injection. Three eyes of 2 patients had a significant decrease in Schirmer test results at 4 months after injection. Only one patient reported dry-eye symptoms at the 4-month follow-up. Schirmer test results of two eyes of one patient remained significantly lower than baseline at 6 months follow-up, which returned to the normal range at 9 months.

CONCLUSIONS

Botulinum toxin for lateral canthal rhytids usually does not suppress tear production. However, decreased tear production after botulinum toxin injection for crow's feet is a possible complication and patients should be advised of the small but definite risk of a temporary dry eye.