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A soft and transparent contact lens for the wireless quantitative monitoring of intraocular pressure


Continuous detection of raised intraocular pressure (IOP) could benefit the monitoring of patients with glaucoma. Current contact lenses with embedded sensors for measuring IOP are rigid, bulky, partially block vision or are insufficiently sensitive. Here, we report the design and testing in volunteers of a soft and transparent contact lens for the quantitative monitoring of IOP in real time using a smartphone. The contact lens incorporates a strain sensor, a wireless antenna, capacitors, resistors, stretchable metal interconnects and an integrated circuit for wireless communication. In rabbits, the lens provided measurements that match those of a commercial tonometer. In ten human participants, the lens proved to be safe, and reliably provided accurate quantitative measurements of IOP without inducing inflammation.

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Fig. 1: Characterizing a strain sensor on a rigid–soft hybrid layer.
Fig. 2: Characterization of the stretchable NFC antenna using the AgNF–AgNW hybrid networks.
Fig. 3: Stretchable interconnections made using direct printing of a liquid metal.
Fig. 4: In vivo performance of the soft contact lens.
Fig. 5: Human study of the soft contact lens.

Data availability

The rabbit in vivo data are available at Figshare ( The human data are available within the paper and its Supplementary Information. The raw and analysed datasets generated for the studies shown in Figs. 13 are available for research purposes from the corresponding authors on reasonable request.


  1. 1.

    Yang, X. et al. Bioinspired neuron-like electronics. Nat. Mater. 18, 510–517 (2019).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  2. 2.

    Xu, S. et al. Soft microfluidic assemblies of sensors, circuits, and radios for the skin. Science 344, 70–74 (2014).

    CAS  PubMed  Article  Google Scholar 

  3. 3.

    Dai, X., Zhou, W., Gao, T., Liu, J. & Lieber, C. M. Three-dimensional mapping and regulation of action potential propagation in nanoelectronics-innervated tissues. Nat. Nanotechnol. 11, 776–782 (2016).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  4. 4.

    Zhang, K. et al. Origami silicon optoelectronics for hemispherical electronic eye systems. Nat. Commun. 8, 1782 (2017).

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  5. 5.

    Anwar, T. et al. p38-mediated phosphorylation at T367 induces EZH2 cytoplasmic localization to promote breast cancer metastasis. Nat. Commun. 9, 2801 (2018).

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  6. 6.

    Gao, W. et al. Fully integrated wearable sensor arrays for multiplexed in situ perspiration analysis. Nature 529, 509–514 (2016).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  7. 7.

    Kim, D.-H. et al. Epidermal electronics. Science 333, 838–843 (2011).

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  8. 8.

    Lipani, L. et al. Non-invasive, transdermal, path-selective and specific glucose monitoring via a graphene-based platform. Nat. Nanotechnol. 13, 504–511 (2018).

    CAS  PubMed  Article  Google Scholar 

  9. 9.

    Chen, G.-Z., Chan, I.-S. & Lam, D. C. C. Capacitive contact lens sensor for continuous non-invasive intraocular pressure monitoring. Sens. Actuators A 203, 112–118 (2013).

    CAS  Article  Google Scholar 

  10. 10.

    Casson, R. J., Chidlow, G., Wood, J. P., Crowston, J. G. & Goldberg, I. Definition of glaucoma: clinical and experimental concepts. Clin. Exp. Ophthalmol. 40, 341–349 (2012).

    PubMed  Article  Google Scholar 

  11. 11.

    Moraes, C. G. V. D. et al. Risk factors for visual field progression in treated glaucoma. Arch. Ophthalmol. 129, 562–568 (2011).

    PubMed  Article  Google Scholar 

  12. 12.

    Renard, E. et al. Twenty-four hour (nyctohemeral) rhythm of intraocular pressure and ocular perfusion pressure in normal-tension glaucoma. Invest. Ophthalmol. Vis. Sci. 51, 882–889 (2010).

    PubMed  Article  Google Scholar 

  13. 13.

    Ku, M. et al. Smart, soft contact lens for wireless immunosensing of cortisol. Sci. Adv. 6, eabb2891 (2020).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  14. 14.

    Moses, R. A. The Goldmann applanation tonometer. Am. J. Ophthalmol. 46, 865–869 (1958).

    CAS  PubMed  Article  Google Scholar 

  15. 15.

    Muir, K. W. Home tonometry-can we? should we? JAMA Ophthalmol. 135, 1036 (2017).

    PubMed  Article  Google Scholar 

  16. 16.

    Hom, M. & Bruce, A. Manual of Contact Lens Prescribing and Fitting with CD-ROM 3rd edn (Butterworth-Heinemann, 2006).

  17. 17.

    Flatau, A. et al. Measured changes in limbal strain during simulated sleep in face down position using an instrumented contact lens in healthy adults and adults with glaucoma. JAMA Ophthalmol. 134, 375–382 (2016).

    PubMed  Article  Google Scholar 

  18. 18.

    Leonardi, M., Pitchon, E. M., Bertsch, A., Renaud, P. & Mermoud, A. Wireless contact lens sensor for intraocular pressure monitoring: assessment on enucleated pig eyes. Acta Ophthalmol. 87, 433–437 (2009).

    PubMed  Article  Google Scholar 

  19. 19.

    Liao, Y. T., Yao, H., Lingley, A., Parviz, B. & Otis, B. P. A 3-μW CMOS glucose sensor for wireless contact-lens tear glucose monitoring. IEEE J. Solid State Circuits 47, 335–344 (2012).

    Article  Google Scholar 

  20. 20.

    Piso, D., Veiga-Crespo, P. & Vecino, E. Modern monitoring intraocular pressure sensing devices based on application specific integrated circuits. J. Biomater. Nanobiotechnol 3, 301–309 (2012).

    Article  Google Scholar 

  21. 21.

    Pandey, J. et al. A fully integrated RF-powered contact lens with a single element display. IEEE Trans. Biomed. Circuits Syst. 4, 454–461 (2010).

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  22. 22.

    Kim, J. et al. Wearable smart sensor systems integrated on soft contact lenses for wireless ocular diagnostics. Nat. Commun. 8, 14997 (2017).

    PubMed  PubMed Central  Article  Google Scholar 

  23. 23.

    Dunbar, G. E., Shen, B. Y. & Aref, A. A. The sensimed triggerfish contact lens sensor: efficiency, safety, and patient perspectives. Clin. Ophthalmol. 11, 875–882 (2017).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  24. 24.

    Park, J. et al. Soft, smart contact lenses with integrations of wireless circuits, glucose sensors, and displays. Sci. Adv. 4, eaap9841 (2018).

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  25. 25.

    Romeo, A., Liu, Q., Suo, Z. & Lacour, S. P. Elastomeric substrates with embedded stiff platforms for stretchable electronics. Appl. Phys. Lett. 102, 131904 (2013).

    Article  CAS  Google Scholar 

  26. 26.

    Robinson, A., Aziz, A., Liu, Q., Suo, Z. & Lacour, S. P. Hybrid stretchable circuits on silicone substrate. J. Appl. Phys. 115, 143511 (2014).

    Article  CAS  Google Scholar 

  27. 27.

    Hjortdal, J. Ø. & Jensen, P. K. In vitro measurement of corneal strain, thickness, and curvature using digital image processing. Acta Ophthalmol. Scand. 73, 5–11 (1995).

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  28. 28.

    Leonardi, M., Leuenberger, P., Bertrand, D., Bertsch, A. & Renaud, P. First steps toward noninvasive intraocular pressure monitoring with a sensing contact lens. Invest. Ophthalmol. Vis. Sci. 45, 3113–3117 (2004).

    PubMed  Article  PubMed Central  Google Scholar 

  29. 29.

    Douthwaite, W. A. & Lam, A. K. C. The effect of an artificially elevated intraocular pressure on the central corneal curvature. Ophthalmic Physiol. Opt. 17, 18–24 (1997).

    PubMed  Article  PubMed Central  Google Scholar 

  30. 30.

    Tadakaluru, S., Thongwusan, W. & Singjai, P. Stretchable and flexible high-strain sensors made using carbon nanotubes and graphite films on natural rubber. Sensors 14, 868–876 (2014).

    PubMed  PubMed Central  Article  CAS  Google Scholar 

  31. 31.

    Yamada, T. et al. A stretchable carbon nanotube strain sensor for human-motion detection. Nat. Nanotechnol. 6, 296–301 (2011).

    CAS  PubMed  Article  Google Scholar 

  32. 32.

    Amjadi, M., Pichitpajongkit, A., Lee, S., Ryu, S. & Park, I. Highly stretchable and sensitive strain sensor based on silver nanowire-elastomer nanocomposite. ACS Nano 8, 5154–5163 (2014).

    CAS  PubMed  Article  Google Scholar 

  33. 33.

    Gong, S. et al. Highly stretchy black gold e-skin nanopatches as highly sensitive wearable biomedical sensors. Adv. Electron. Mater. 1, 1400063 (2015).

    Article  CAS  Google Scholar 

  34. 34.

    Yang, S. & Lu, N. Gauge factor and stretchability of silicon-on-polymer strain gauges. Sensors 13, 8577–8594 (2013).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  35. 35.

    Kim, D.-H. et al. Electronic sensor and actuator webs for large-area complex geometry cardiac mapping and therapy. Proc. Natl Acad. Sci. USA 109, 19910–19915 (2012).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  36. 36.

    Hoffmann, E. M., Grus, F.-H. & Pfeiffer, N. Intraocular pressure and ocular pulse amplitude using dynamic contour tonometry and contact lens tonometry. BMC Ophthalmol. 4, 4 (2004).

    PubMed  PubMed Central  Article  Google Scholar 

  37. 37.

    Lee, J. O. et al. A microscale optical implant for continuous in vivo monitoring of intraocular pressure. Microsyst. Nanoeng. 3, 17057 (2017).

    CAS  PubMed  PubMed Central  Article  Google Scholar 

  38. 38.

    Kim, K. H., Lee, J. O., Du, J., Sretavan, D. & Choo, H. Real-time in vivo intraocular pressure monitoring using an optomechanical implant and an artificial neural network. IEEE Sens. J. 17, 7394–7404 (2018).

    Article  Google Scholar 

  39. 39.

    Kim, J. et al. Epidermal electronics with advanced capabilities in near-field communication. Small 11, 906–912 (2015).

    CAS  PubMed  Article  Google Scholar 

  40. 40.

    Kim, J. et al. Miniaturized flexible electronic systems with wireless power and near-field communication capabilities. Adv. Funct. Mater. 25, 4761–4767 (2015).

    CAS  Article  Google Scholar 

  41. 41.

    Tao, H. et al. Silk‐based conformal, adhesive, edible food sensors. Adv. Mater. 24, 1067–1072 (2012).

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  42. 42.

    Cheng, S. & Wu, Z. Microfluidic, reversibly stretchable, large-area wireless strain sensor. Adv. Funct. Mater. 21, 2282–2290 (2011).

    CAS  Article  Google Scholar 

  43. 43.

    Kim, J. et al. Highly transparent and stretchable field-effect transistor sensors using graphene–nanowire hybrid nanostructures. Adv. Mater. 27, 3292–3297 (2015).

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  44. 44.

    Mujal, J. et al. Inkjet printed antennas for NFC systems. In Proc. 17th IEEE International Conference on Electronics, Circuits and Systems 1220–1223 (IEEE, 2010).

  45. 45.

    Li, S., Sun, F., An, D. & He, S. Increasing efficiency of a wireless energy transfer system by spatial translational transformation. IEEE Trans. Power Electron. 99, 3325–3332 (2017).

    Google Scholar 

  46. 46.

    Ladd, C., So, J.-H., Muth, J. & Dickey, M. D. 3D printing of free standing liquid metal microstructures. Adv. Mater. 25, 5081–5085 (2013).

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  47. 47.

    IEEE Standard for Safety Levels with Respect to Human Exposure to Radio Frequency Electromagnetic Fields, 3 kHz to 300 GHz IEEE Std C95.1-2005 (Revision of IEEE Std C95.1-1991), 1–238 (IEEE, 2006).

  48. 48.

    Standard Guide for Accelerated Aging of Sterile Barrier Systems for Medical Devices ASTM F1980‐07 (American Society for Testing Materials, 2011).

  49. 49.

    Efron, N. Grading scales for contact lens complications. Ophthalmic Physiol. Opt. 18, 182–186 (1998).

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  50. 50.

    First, P. G. et al. The influence of soft contact lenses on the intraocular pressure measurement. Eye 26, 278–282 (2012).

    Article  Google Scholar 

  51. 51.

    Realini, T., Weinreb, R. N. & Wisniewski, S. R. Diurnal intraocular pressure patterns are not repeatable in the short-term in healthy individuals. Ophthalmology 117, 1700–1704 (2010).

    PubMed  Article  Google Scholar 

  52. 52.

    Kim, J. et al. Dataset for ‘A soft and transparent contact lens for the wireless quantitative monitoring of intraocular pressure’. Figshare (2020).

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This work was supported by the Ministry of Science & ICT (MSIT) and the Ministry of Trade, Industry and Energy (MOTIE) of Korea through the National Research Foundation (2019R1A2B5B03069358 and 2016R1A5A1009926), the Bio & Medical Technology Development Program (2018M3A9F1021649), the Nano Material Technology Development Program (2016M3A7B4910635) and the Technology Innovation Program (20010366 and 20013621, Center for Super Critical Material Industrial Technology). We also acknowledge financial support from the Institute for Basic Science (IBS-R026-D1), the Research Program (2019-22-0228) and the Post Doc Researcher Supporting program of 2019 (2019-12-0010) funded by Yonsei University.

Author information




Joohee Kim and J.P. carried out the experiments, analysed the data and wrote the manuscript. Y.-G.P. performed the experiments related to the printing of stretchable 3D interconnects. E.C. and M.K. performed the fabrication of contact lenses. H.S.A. participated in the design of stretchable antennas. K.-P.L. and M.-I.H. participated in the in vivo experiments. Junmo Kim and T.-S.K. performed the DIC experiments. D.W.K., H.K.K. and J.-U.P. oversaw all of the research phases and revised the manuscript. All of the authors discussed and commented on the manuscript.

Corresponding authors

Correspondence to Dai Woo Kim or Hong Kyun Kim or Jang-Ung Park.

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Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Biomedical Engineering thanks the anonymous reviewers for their contribution to the peer review of this work.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Methods, Figs. 1–30 and Table 1, and captions for Supplementary Videos 1–3.

Reporting Summary

Supplementary Dataset

IOP data for the ten human volunteers.

Supplementary Video 1

In vivo trial of the soft contact lens for recording IOP.

Supplementary Video 2

In vivo test conducted using a live rabbit for monitoring the generation of heat during the wireless operation of the contact lens.

Supplementary Video 3

Human pilot trial of the soft contact lens.

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Kim, J., Park, J., Park, YG. et al. A soft and transparent contact lens for the wireless quantitative monitoring of intraocular pressure. Nat Biomed Eng 5, 772–782 (2021).

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