Restoration of Natural Blink after Facial Paralysis: An Electro-mechanical Intervention

Abstract

The loss of the ability to blink is considered the most severe effect of facial nerve paralysis (FNP). The delicate homeostasis of the eye is disrupted, and without frequent intervention, the cornea can become damaged, ultimately resulting in blindness. The psychosocial impact is also significant, with individuals withdrawing from society to hide what they perceive to be a disfigurement. Surgical and engineering interventions have been devised to reanimate blink, however, a solution has yet to be designed which addresses both functional and aesthetic concerns.

In this thesis, the design and assessment of a novel implantable electromagnetic actuator to restore the capacity to blink is reported. The implant utilised a modifiable mechanical force to elicit downward motion of the eyelid, generating biomimetic movement to replicate natural blinking and fill an important gap in clinical patient care. A proof-of-concept device was prioritised, to understand the safety and biocompatibility of the novel mechanical forces produced.

The electrical and mechanical development of the implant is described, followed by the assessment of a custom tool to analyse the dynamic characteristics of blink. A chronic implantation study in an ovine model of facial nerve paralysis is reported which tested both safety and device functionality. Findings from a human cadaver implantation are discussed, providing insight into anatomical requirements and informing future device development.

Overall, the device demonstrates strong potential to address both the functional and aesthetic concerns of patients with FNP, supporting its continued development toward clinical application. This research represents a significant advance in the field of facial reanimation and implantable medical devices.