Dry Eye Disease in Hemifacial Spasm Patients Treated with Botulinum Toxin Type A

PURPOSE: To assess the impact of botulinum toxin type A (BTX-A) on signs and symptoms of dry eye (DE) in affected eye of hemifacial spasm (HFS) patients and to compare the prevalence of DE between affected and non-affected eye in HFS patients. PATIENTS AND METHODS: This prospective study included participants with unilateral HFS, who received BTX-A injection as a treatment. The eyes ipsilateral to the spasm side were used as studied eyes and the contralateral eyes were used as controls. The Ocular Surface Disease Index (OSDI) score, tear break-up time (TBUT), corneal fluorescein staining, and Schirmer I test were measured at baseline, 1 and 3 months after BTX-A injection. Fluorescein clearance test (FCT) was evaluated at baseline and at 1 month after BTX-A injection. RESULTS: Thirty-one participants (6 males and 25 females; mean age 61±10 years) were included. The prevalence of DE according to the Asia Dry Eye Society was not significantly different between affected (37.93%) and non-affected eyes (27.6%); P=0.083. At baseline, there was no significant difference in TBUT, Schirmer test, basal tear secretion, presence of delayed tear clearance, and presence of reflex tear secretion between affected and non-affected eyes, while significant difference in Oxford scheme grade was observed (P=0.031). OSDI score, TBUT, Oxford scheme grade, and Schirmer test at 1 month (P=0.817, 0.796, 0.534, 0.556), and 3 months (P=0.803, 0.904, 0.936, 0.684) after BTX-A injection did not significantly change from baseline in affected eyes. FCT results were not significantly different between baseline and at 1-month follow-up in both groups. All findings were corresponding in both naïve and long-term botulinum toxin injection groups. CONCLUSION: We found no significant effect of BTX-A on signs and symptoms of DE in patients with HFS. Moreover, there was no significant association between HFS and DE. However, we found significant corneal surface damage in the affected eyes, which emphasized importance of ocular surface evaluation and prompt treatment in HFS patients.