title: Soft wearable contact lens sensor for continuous intraocular pressure monitoring.
abstract: Intraocular pressure (IOP) is a primary indicator of glaucoma, but measurements from a single visit to the clinic miss the peak IOP that may occur at night during sleep. A soft chipless contact lens sensor that allows the IOP to be monitored throughout the day and at night is developed in this study. A resonance circuit composed of a thin film capacitor coupled with a sensing coil that can sense corneal curvature deformation is designed, fabricated and embedded into a soft contact lens. The resonance frequency of the sensor is designed to vary with the lens curvature as it changes with the IOP. The frequency responses and the ability of the sensor to track IOP cycles were tested using a silicone rubber model eye. The results showed that the sensor has excellent linearity with a frequency response of ∼8 kHz/mmHg, and the sensor can accurately track fluctuating IOP. These results showed that the chipless contact lens sensor can potentially be used to monitor IOP to improve diagnosis accuracy and treatment of glaucoma.
authors.affiliation: The Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong. Electronic address: eeguozhen@ust.hk.
authors.forename: Guo-Zhen
authors.initials: GZ
authors.lastname: Chen
authors.affiliation: The Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong. Electronic address: ion@ust.hk.
authors.forename: Ion-Seng
authors.initials: IS
authors.lastname: Chan
authors.affiliation: The Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong. Electronic address: leoleung@ust.hk.
authors.forename: Leo K K
authors.initials: LK
authors.lastname: Leung
authors.affiliation: The Department of Mechanical and Aerospace Engineering, The Hong Kong University of Science and Technology, Hong Kong. Electronic address: david.lam@ust.hk.
authors.forename: David C C
authors.initials: DC
authors.lastname: Lam
mesh_terms: D000465:Algorithms; D003263:Contact Lenses, Hydrophilic; D004867:Equipment Design; D005240:Feasibility Studies; D005901:Glaucoma / Q000175:diagnosis; D006801:Humans; D007429:Intraocular Pressure; D016014:Linear Models; D008954:Models, Biological; D018670:Monitoring, Ambulatory / Q000295:instrumentation* / Q000379:methods; D012826:Silicone Elastomers; D014065:Tonometry, Ocular / Q000295:instrumentation* / Q000379:methods
chemical_list: D012826:Silicone Elastomers
keywords: Contact lens sensor; Glaucoma; Intraocular pressure; Resonance circuit