A Semi-Passive Smart Contact Lens with On-Lens Storage Element

This study presents a semi-passive smart contact lens (SCL) platform for sensor and actuator applications. It focuses on design improvements made prior to human clinical trials involving basic considerations on comfort and safety, which are verified through animal studies. Observations of tissue temperature variation and post-trial surgery examinations confirm that the 50 μW on-lens wireless power delivery reduces the impact on tissue of previously reported SCL. Migration of wirelessly-powered radio frequency identification (RFID)-based passive SCLs to semi-passive systems is enabled with the proposed on-lens storage element. Furthermore, a switched capacitor converter extends the active time of the storage element and reduces electromagnetic influence.