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Updated: Jan 20, 2026

Ultrasound-guided Botulinum Toxin-A Injections: A Method of Treating Sialorrhea
Published on: November 9, 2016
Ocular surface status in patients with hemifacial spasm under long-lasting treatment with botulinum A toxin: A
Marco Pellegrini1, Costantino Schiavi1, Leonardo Taroni1
1Department of Ophthalmology, S.Orsola-Malpighi University Hospital, University of Bologna, Bologna, Italy.
Purpose:
The purpose of this study was to assess the effect of long-lasting botulinum A toxin injections on ocular surface parameters and to further investigate the relationship between these parameters and the duration of the treatment.
Methods:
In this retrospective study, patients with unilateral hemifacial spasm who were receiving botulinum A toxin injections for at least 1 year were analyzed. Healthy contralateral eyes acted as controls. The ocular surface examination included Ocular Surface Disease Index questionnaire, Schirmer test type I, tear film break-up time (TFBUT), tear osmolarity, corneal sensitivity, and corneal fluorescein staining.
Results:
Twenty-six patients (6 males and 20 females; mean age 76.4 ± 8.9 years) were included in the study. The mean duration of the treatment was 7.2 ± 5.4 years, and the mean frequency of injections was of one every 3.3 ± 0.4 months. TFBUT, Schirmer test, and corneal sensitivity were significantly lower in the eye homolateral to hemifacial spasm compared with the contralateral one (5.9 ± 3.2 vs 7.5 ± 4.2 s, P = 0.001; 6.2 ± 3.4 vs 9.2 ± 6.6 mm, P = 0.031; 50.8 ± 3.7 mm vs 52.3 ± 2.9 mm, P = 0.048, respectively). One month after the last injection, TFBUT further decreased from 5.9 ± 3.2 to 2.3 ± 1.2 s (P = 0.028). A significant positive correlation was found between the duration of treatment and tear osmolarity (ρ = 0.542, P = 0.025).
Conclusion:
Patients with hemifacial spasm under long-lasting treatment with serial botulinum A toxin injections showed a reduction in tear film production and stability, as well as corneal sensitivity in the treated eye compared with the contralateral one. Tear film stability further decreased 1 month after the last injection.
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