Tear film lipid layer thickness and blink dynamics in patients with blepharospasm

This study investigates the effect of botulinum toxin A on lipid layer thickness (LLT) and blink dynamics in patients with benign essential blepharospasm (BEB) compared to dry eye disease (DED) patients.

We reviewed the medical records of patients with dry eye disease (DED) and BEB treated with botulinum toxin A (BoT A) injections. Data on demographics, lipid layer thickness (LLT), meiboscore, and blink dynamics measured using a LipiView II interferometer before and 2 months after BoT A were collected.

Each 28 eyes from 28 patients with BEB and age- and sex-matched patients with DED were included. When comparing blink dynamics, complete blink rate was significantly higher in the pre-injection BEB group compared to the DED group (5.25 ± 4.32 times/20 s vs. 2.43 ± 2.82 times/20 s, p = 0.0055). In tear film lipid profiles analyzed in BEB patients at pre-injection and 2-month follow-up after injection, average LLT significantly increased after injection (72.4 ± 22.7 nm to 83.0 ± 22.2 nm, p = 0.0215). Diabetes and young age were associated factors influencing the LLT increase. Significant increase in LLT was observed post-injection, with specific demographic factors, including diabetes and age, associated with this improvement. Additionally, blink dynamics showed a decrease in complete blink rate post-injection.

These findings suggest that BoT-A may alleviate BEB symptoms, but ophthalmologists should carefully interpret LLT and blink patterns in BEB patients due to potential overestimations of blink efficacy by the interferometer.