Ocular surface side effects of botulinum toxin type A injections in the treatment of lateral canthal wrinkles (Crow's Feet).

[PURPOSE] This study investigates the impact of Botulinum Toxin Type A (BoNT-A) injections for lateral canthal wrinkles on the ocular surface.

[METHODS] A total of 30 patients (30 eyes) who received BoNT-A injections were followed over a three-month period. Evaluations included tear meniscus height (TMH), strip meniscometry test, fluorescein tear film break-up time (FTBUT), corneal staining score, meibomian gland orifice and meibum quality score. Observations were recorded at baseline, one week, one month, and three months post-injection.

[RESULTS] Upper and total eyelid meiboscore, meibomian gland orifice obstruction, and meibum quality score peaked at three months post-injection, while FTBUT was shortest during the same period, with significant differences observed across time points (P < 0.05). Post-hoc analysis indicated a significant reduction in FTBUT between baseline and three months (P = 0.048). Corneal staining scores were highest at one week, with significant differences across time points (P < 0.001); post-hoc analysis revealed a significant difference between one week and three months (P = 0.037). No significant changes were found in TMH or strip meniscometry test score (P = 0.374, P = 0.732).

[CONCLUSIONS] BoNT-A injections may temporarily compromise ocular surface stability by decreasing tear film stability, disrupting meibomian gland function, and causing corneal epithelial disruption.