Continuous 24-hour measurement of intraocular pressure in millimeters of mercury (mmHg) using a novel contact lens sensor: Comparison with pneumatonometry

PLoS One. 2021 Mar 23;16(3):e0248211. doi: 10.1371/journal.pone.0248211. eCollection 2021.

Abstract

Purpose: To address the unmet need of continuous IOP monitoring, a Pressure-Measuring Contact Lens (PMCL) was developed to measure IOP in millimeters of mercury (mmHg) continuously over 24 hours. The present study assessed the reliability of the novel PMCL.

Methods: In this prospective open-label clinical study, healthy and open-angle glaucoma (OAG) subjects were fitted with the PMCL, and pneumatonometry was performed on study eyes (in absence of the PMCL) and on fellow eyes before, during, and after provocative tests. The primary outcome measures were (1) mean IOP difference between same-eye measurements, and (2) percentage of timepoints at which IOP measured by the PMCL was within 5 mmHg of that measured by pneumatonometry in the fellow eye.

Results: Eight subjects were analysed (4 healthy, 4 OAG). The average difference in successive IOP measurements made by pneumatonometry and with the PMCL was 2.0±4.3mmHg at placement-time, and 6.5±15.2mmHg at removal time. During water drinking test, a significant increase in IOP was detected both by PMCL in the study eye (2.4±2.5mmHg, p = 0.03) and by pneumatonometry in the fellow eye (1.9±1.9mmHg, p = 0.02). Over the 24-hour recording, 88.0% of IOP variations measured by the PMCL were within 5mmHg of that measured with the pneumatonometer in the fellow eye. A transient corneal erosion of severe intensity was observed following removal of the PMCL on one single eye, and may have affected measurement accuracy in that eye.

Conclusions: This study is a proof-of-concept for this novel PMCL, and its results are encouraging, with a fair accuracy in IOP values measurement and good sensitivity to subtle IOP variations.

Publication types

  • Clinical Trial
  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Contact Lenses*
  • Female
  • Glaucoma, Open-Angle / diagnosis
  • Humans
  • Intraocular Pressure*
  • Male
  • Middle Aged
  • Prospective Studies
  • Reproducibility of Results
  • Time Factors
  • Tonometry, Ocular / instrumentation*
  • Tonometry, Ocular / methods

Grants and funding

The study was sponsored by Sensimed AG, Lausanne, Switzerland. The sponsor supplied the study devices and participated in the design of the study, data collection, data management, data analysis and preparation of the manuscript. Sensimed AG also provided funding for this study in the form of a salary for SSZ. The specific roles of this author are articulated in the ‘author contributions’ section.