Liquid Metal Enabled Flexible Electronic System for Eye Movement Tracking

Eye movement tracking is concerned with many important areas of research, of which tracking with a traditional scleral search coil system is deemed the gold standard. However, since such coil system requires anaesthetic use due to the stiffness of the copper wire coil in the system, it is of great importance to improve the wearing sensation experience. Here, an innovative electronic system for eye movement recording is proposed and realized, in which a liquid metal coil is introduced as the core element, attempting to provide a comfortable eye sensation. Theoretical investigation shows that this type of coil has performance similar to the traditional copper coil, which implies it is suitable for eye movement tracking. It has been demonstrated that such liquid metal coil is soft, flexible, and easy to produce, indicating that the coil is potentially favorable as a wearable medical device. Experiments show that the variance fitting curve between the induced voltage and rotation angle measured with the liquid metal coil during eye movement accords well with that of the classical copper scleral search coil, with both determination coefficients over 0.98, which confirms the reliability of the new coil. Overall, the feasibility of the liquid metal coil system suggests a useful approach for detecting human eye movement behavior and related diseases, which may facilitate disease diagnosis and prediction.