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Precision Wireless Implantable Continuous Intraocular Pressure Sensors Utilizing Parylene-on-oil Encapsulation

Rodger, Damien C. and Shapero, Aubrey and Agarwal, Abhinav and Emami, Azita and Humayun, Mark S. and Tai, Yu-Chong (2018) Precision Wireless Implantable Continuous Intraocular Pressure Sensors Utilizing Parylene-on-oil Encapsulation. Investigative Ophthalmology and Visual Science, 59 (9). Art. No. 1997. ISSN 0146-0404. http://resolver.caltech.edu/CaltechAUTHORS:20180926-123802831

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Abstract

Purpose : To demonstrate the precision of a first of its kind fully implantable continuous wireless pressure sensor that measures true intraocular pressure (IOP) and leverages commercially fabricated microelectromechanical (MEMS) components with embedded temperature compensation to ensure superb reliability. Methods : The continuous IOP sensor, with a form factor similar to an aqueous shunt, is designed to be implanted with the electronics in the superotemporal or inferotemporal subtenon's space with a flexible 23-gauge silicone tube permanently inserted into the anterior chamber or the pars plana. It consists of a parylene-on-oil packaged LPS25H MEMS barometer with temperature compensation (STMicroelectronics, Geneva, Switzerland), capacitors, and a custom designed integrated circuit, all assembled on a flexible polyimide substrate. Devices were tested on the benchtop. Ex vivo porcine eyes were vitrectomized, and the IOP sensor tube placed into the pars plana through one of the sclerotomies. The IOP was varied using the pressure setting on the vitrector, and resultant pressure readings from the sensor were analyzed. Results : Photographs of the fabricated device are shown in Fig. 1(a-b).1 In air, the wireless device has demonstrated 0.17 mmHg pressure sensitivity. Accelerated-lifetime saline soak testing of the packaged barometer itself has demonstrated stability for an extrapolated 20 months to date. A photograph of the ex vivo wireless porcine eye setup is shown in Fig. 1c. In addition to excellent precision during IOP sweeps, a step from 5 to 75 resulted in a 69.92 mmHg change as measured by the sensor (Fig. 2). A slow ramp down after changing the setting on the vitrector back to 5 mmHg is seen because the eye is essentially a closed system. Conclusions : A breakthrough wireless IOP sensor has been realized utilizing a commercially fabricated barometer and a custom integrated circuit as its backbone. All testing to date, including ex vivo porcine data, demonstrates superior reliability and precision.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://iovs.arvojournals.org/article.aspx?articleid=2694000PublisherArticle
ORCID:
AuthorORCID
Emami, Azita0000-0003-2608-9691
Tai, Yu-Chong0000-0001-8529-106X
Additional Information:© 2018 This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License. Commercial Relationships: Damien Rodger, None; Aubrey Shapero, None; Abhinav Agarwal, None; Azita Emami, None; Mark Humayun, None; Yu-Chong Tai, None. Support: L. K. Whittier Foundation, Rosen Bioengineering Center Pilot Grant, Heritage Medical Research Institute, and an unrestricted departmental grant from Research to Prevent Blindness.
Group:Heritage Medical Research Institute
Funders:
Funding AgencyGrant Number
L. K. Whittier FoundationUNSPECIFIED
Donna and Benjamin M. Rosen Bioengineering CenterUNSPECIFIED
Heritage Medical Research InstituteUNSPECIFIED
Research to Prevent BlindnessUNSPECIFIED
Record Number:CaltechAUTHORS:20180926-123802831
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20180926-123802831
Official Citation:Damien C Rodger, Aubrey Shapero, Abhinav Agarwal, Azita Emami, Mark S. Humayun, Yu-Chong Tai; Precision Wireless Implantable Continuous Intraocular Pressure Sensors Utilizing Parylene-on-oil Encapsulation. Invest. Ophthalmol. Vis. Sci. 2018;59(9):1997
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:89960
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:26 Sep 2018 21:37
Last Modified:26 Sep 2018 21:37

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