Osaki MH, Osaki TH, Garcia DM, Osaki T, Gameiro GR, Belfort R Jr, Cruz AAV. Analysis of blink activity and anomalous eyelid movements in patients with hemifacial spasm. Graefes Arch Clin Exp Ophthalmol 2020; 258(3): 669-74.
Hemifacial spasm (HFS) is a condition characterized by involuntary spasms of the muscles innervated by the ipsilateral facial nerve. It is a unique condition in which complex patterns of eyelid movements, including both conjugate (spontaneous blinking) and nonconjugate (anomalous) movements are present. Our study aimed to assess spontaneous blinking and anomalous eyelid movements in patients with hemifacial spasm. Spontaneous eyelid movements were registered bilaterally for 3 minutes using a high-speed video camera in patients with hemifacial spasm (HFS) who had not been treated with botulinum toxin injections for at least 5 months. 82% of patients presented with abnormal nonconjugate spasms that were similar to blinks, and in 61%, high-frequency eyelid twitches were detected between blinks on the affected eye. With regard for conjugate blinks, there was no significant interocular difference in amplitudes or eyelid closure velocities. The amplitude and velocity were significantly lower for nonconjugate movements than for spontaneous blinks.