An implantable microfluidic device for self-monitoring of intraocular pressure

Abstract

Glaucoma is the second most common cause of blindness in the world. It is a multifactorial disease with several risk factors, of which intraocular pressure (IOP) is a primary contributing factor. IOP measurements are used for glaucoma diagnosis and patient monitoring. IOP has wide diurnal fluctuation and is dependent on body posture, so the occasional measurements done by the eye care expert in the clinic can be misleading. Here we show that microfluidic principles can be used to develop an implantable sensor that has a limit of detection of 1 mm Hg, high sensitivity and excellent reproducibility. This device has a simple optical interface that enables IOP to be read with a smartphone camera. This sensor, with its ease of fabrication and simple design, as well as its allowance for IOP home monitoring, offers a promising approach for better care of patients with glaucoma.

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Figure 1: IOP measurement system embedded in an intraocular lens.
Figure 2: Microfluidic intraocular sensor.
Figure 3: IOP sensor implanted in a porcine eye.
Figure 4: IOP readout with a smartphone.

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Acknowledgements

The authors acknowledge Z. Zalevsky and A. Rudnitsky for performing the Zemax simulation, S. Liu for making the molds that were used in this project and T. Halevy for making the artistic drawing of Figure 1.

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Affiliations

Authors

Contributions

Y.M., S.R.Q. and I.E.A. designed the IOP sensor chip. I.E.A. and B.S. fabricated the chip. Y.M. and I.E.A. conducted the experiments and wrote the manuscript.

Corresponding authors

Correspondence to Stephen R Quake or Yossi Mandel.

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Competing interests

Stanford University has applied for a patent to the US patent office on the IOP sensor technology (application number PCT/US2014/019660).

Supplementary information

Supplementary Text and Figures

Supplementary Note and Supplementary Figures 1–6 (PDF 892 kb)

Microfluidic intraocular pressure.

(a) Shift of air-fluid interface in and IOP sensor in response to pressure changes in a pressure chamber. (b) Response of IOP sensor implanted in a porcine eye to IOP modification ex vivo, as captured by a surgical microscope. (c) Response of IOP sensor implanted in a porcine eye to IOP modification ex vivo, as captured by an iPhone 4S video camera. (AVI 4954 kb)

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Araci, I., Su, B., Quake, S. et al. An implantable microfluidic device for self-monitoring of intraocular pressure. Nat Med 20, 1074–1078 (2014). https://doi.org/10.1038/nm.3621

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