Creating eye closure in patients with facial nerve paralysis using an implantable solenoid actuator

This paper proposes the use of an implantable solenoid actuator to create a more natural eyelid closure over current lid loading therapies in patients with facial nerve paralysis (FNP). The actuator works by moving a magnet when a solenoid is activated. This is used to tension a sling applied to the upper eyelid which closes the eye. The sling design has been described elsewhere and creating eye closure using it requires a force of 627 (± 128) mN over a movement of approximately 6 mm. The actuator described here was able to successfully achieve these parameters and repeatedly perform eyelid closure in a cadaveric rabbit model. Device limitations and future improvements have also been identified and discussed.