Intraocular pressure measurement using surface acoustic wave optical coherence elastography (SAW-OCE)

Zhang, Yilong; Feng, Zhengshuyi; Scott, Robert; Yang, Ying; Li, Chunhui; Huang, Zhihong

Abstract

IOP is a key parameter in glaucoma progression and is estimated using tonometry. No current tonometer is capable of directly measuring IOP, and very few have been studied against live manometry. Goldmann applanation tonometry is considered the gold standard of tonometry. However, this method is known to have significant inaccuracies notably operator error and variation related to corneal thickness. In addition, it often underestimates high IOP due to its flattening-based measurement method.This study presents an surface acoustic wave optical coherence elastography (SAW-OCE)-based approach for accurately measuring IOP. Corneal geometry and biomechanics were obtained through OCT structural imaging and air-pulse-induced wave imaging. IOP was then calculated using an inversion model. The method was evaluated on in situ porcine eye-globes that were artificially controlled IOPs set at 20, 30, and 40 mmHg. Our findings demonstrated that the OCE-based approach provided IOP measurements of 21.8±3.6 mmHg, 33.4±3.5 mmHg, and 45.0±4.7 mmHg, respectively, which are more closely aligned with the IOPs than those obtained from a conventional tonometer, which recorded 8.5 mmHg, 20.6 mmHg, and 29.0 mmHg. Paired t-tests further confirmed that the OCE method provides highly accurate measurements closely matching the artificial IOPs. The elastography-based system appears to be more accurate at higher pressures and this would make it a clinically safer method of IOP estimation.

Citation

Zhang, Y., Feng, Z., Scott, R., Yang, Y., Li, C., & Huang, Z. (2024). Intraocular pressure measurement using surface acoustic wave optical coherence elastography (SAW-OCE). . https://doi.org/10.1109/uffc-js60046.2024.10793520

• Conference Name: 2024 IEEE Ultrasonics, Ferroelectrics, and Frequency Control Joint Symposium (UFFC-JS)
• Conference Location: Taipei, Taiwan
• Start Date: Sep 22, 2024
• End Date: Sep 26, 2024
• Acceptance Date: Sep 22, 2024
• Online Publication Date: Dec 18, 2024
• Publication Date: Sep 22, 2024
• Deposit Date: Jan 30, 2025
• Publisher: Institute of Electrical and Electronics Engineers (IEEE)
• Pages: 1-3
• ISBN: 979-8-3503-7191-8
• DOI: https://doi.org/10.1109/uffc-js60046.2024.10793520
• Keywords: Intraocular pressure (IOP) , optical coherence elastography (OCE) , Corneal geometry , Corneal biomechanics
• Public URL: https://keele-repository.worktribe.com/output/1051611