Non-Invasive Wireless and Passive MEMS Intraocular Pressure Sensor Based on Flexible Substrate

Abstract:

The intraocular pressure (IOP) is an indicator for the diagnosis and treatment of glaucoma. The traditional measurement of IOP cannot provide a continuous measurement within 24 hours with compromised functionality in glaucoma diagnosis. This paper presents a wireless, passive and non-invasive contact lens sensor (CLS) for continuous monitoring of IOP based on the flexible substrate. This curvature-sensitive sensor includes an inductor and two capacitors to form a C-L-C resonant circuit, which were embedded in parylene C using PDMS as the intermediate medium layer. The C-L-C resonant circuit is used for passive and wireless sensing and simplifying the wireless bonding step. Compared to parylene C, PDMS has a much lower Young Modulus, enabling the quantification of the sensor curvatures, as an indicator of IOP. To fit human eyeballs, the size of the sensor was designed as follows: the outer diameter: 12 mm, the radius of curvature: 8.5 mm. The sensor was characterized in vitro to obtain the frequency response, and the results show that the sensor has a linearity R>0.97 and a sensitivity>9.7 kHz/kPa. This sensor can be used to monitor IOP together with the reading circuit continuously, enabling the diagnosis of glaucoma without impacting the daily life of users.

• Periodical: Applied Mechanics and Materials (Volume 748)
• Pages: 115-127
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.748.115
• Online since: April 2015
• Authors: Li Juan Liu, Jun Bo Wang*, De Yong Chen, Jian Chen
• Keywords: Intraocular Pressure Sensor, MEMS, Non-Invasive, Parylene C, Passive, Wireless

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