Non Invasive Sensor for Continuous Intraocular Pressure Monitoring

Abstract

Pathological elevated intraocular pressure (IOP) is a primary index for glaucoma. In this paper, we present a biocompatible IOP sensor that operates based on the principle of inductorcapacitor (LC) resonance. The IOP sensor is composed solely of a spiral inductor that can sense deformations of corneal curvature. The inductor is fabricated by embedding gold coils into polydimethylsiloxane (PDMS), a soft, biologically compatible material, via MEMS technology. The resonant frequency of the sensor is designed to vary when the IOP is changed in experiments. The frequency response of the sensor is tested using a model eye, a tube, and a network analyzer. The results show that there is approximately linearity between the frequency response of the sensor and the IOP. The sensitivity of the sensor is 417.29 kHz/mmHg, when the pressure ranges from 7.5 to 36.88 mmHg. Consequently, an unstable IOP could be accurately tracked, using the calibrated relationship between frequency response and the IOP.