Electrical Stimulation of Eye Blink in Individuals with Dry Eye Symptoms Caused by Chronic Unilateral Facial Palsy

The aim was to validate the functionality and subjective experiences of timer-triggered electrical blink stimulation with participants (N = 6) suffering from dry eye symptoms caused by chronic unilateral facial palsy. In a stimulation condition, the muscles responsible for eye blinking were stimulated at fixed intervals while watching a video for about 120 min. In a control condition, the participants watched a video without stimulation. The participants rated their dry eye symptoms with a questionnaire before and after the both conditions. They also rated the levels of felt pain, discomfort and naturalness of the stimulated movement. Additionally, the magnitude of the stimulated eye blinks over time was evaluated. The results showed that the magnitude of the stimulated eye blink did not decrease significantly during the watching task. The stimulation was rated as painless, slightly uncomfortable, and fairly natural. The experienced eye dryness decreased significantly in the stimulation condition. Most participants got used to the stimulation, or even forgot it during the task. The findings are promising in respect to the use of timer-triggered blink stimulation.