Determination of palpebral closure using a hall sensor magnet pair

Abstract

A small device that can detect eyelid closure was designed using a Hall sensor and magnet. The ability of the sensor to differentiate blinks from saccadic motion is of vital interest in development of a device to alleviate complications of facial nerve paralysis. Twelve physically normal human subjects were used in this study. A small Hall sensor (3 x 2.5 x 1.1 mm), a device that detects magnetic fields, was attached to the lower eyelid near the lid margin, and an opposing small magnet (3 x 2 x 1 mm) was attached to the upper eyelid, also near the lid margin. Output potentials from the Hall sensor were monitored during eye blinks and saccadic eye movements to correlate sensor potentials with eye movements. Results indicate that the Hall sensor is effective at determining palpebral closure and discriminating eye closure from other eye movements. Therefore, we conclude that the Hall sensor is a reliable means for determining palpebral closure and is ideally suited for use in a facial prosthesis that uses the normal blink as a trigger to reanimate the contralateral paralyzed eyelid.

Validation of Objective Measures for Facial Paralysis

“…This method has not become popular. Light‐emitting diodes and magnetic sensors have been attached to the face to quantitatively measure facial movement 26,27 . In advance of and paralleling these efforts to categorize and quantify facial paralysis, huge, complex, computer image graphics systems were being developed.…”

Evaluation of the hall‐effect sensor for determination of eyelid closure in vivo

“…Prior investigations have shown that when externally applied Hall sensor and magnet pairs can reliably determine palpebral closure in human beings 8 . Hall‐effect sensors have also been used to determine physiologic movement 9 , 11 .…”