Phase-sensitive optical coherence tomography characterization of pulse-induced trabecular meshwork displacement in ex vivo nonhuman primate eyes

Peng Li; Roberto Reif; Zhongwei Zhi; Tueng Shen; Ruikang K. Wang; Elizabeth Martin; Murray Johnstone

doi:10.1117/1.JBO.17.7.076026

24 July 2012 Phase-sensitive optical coherence tomography characterization of pulse-induced trabecular meshwork displacement in ex vivo nonhuman primate eyes

Peng Li, Roberto Reif, Zhongwei Zhi, Tueng Shen, Ruikang K. Wang, Elizabeth Martin, Murray Johnstone

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Journal of Biomedical Optics, Vol. 17, Issue 7, 076026 (July 2012). https://doi.org/10.1117/1.JBO.17.7.076026

Abstract

Glaucoma is a blinding disease for which intraocular pressure (IOP) is the only treatable risk factor. The mean IOP is regulated through the aqueous outflow system, which contains the trabecular meshwork (TM). Considerable evidence indicates that trabecular tissue movement regulates the aqueous outflow and becomes abnormal during glaucoma; however, such motion has thus far escaped detection. The purpose of this study is to describe anovel use of a phase-sensitive optical coherence tomography (PhS-OCT) method to assess pulse-dependent TM movement. For this study, we used enucleated monkey eyes, each mounted in an anterior segment holder. A perfusion system was used to control the mean IOP as well as to provide IOP sinusoidal transients (amplitude 3 mmHg, frequency 1 pulse/second) in all experiments. Measurements were carried out at seven graded mean IOPs (5, 8, 10, 20, 30, 40, and 50 mm Hg). We demonstrate that PhS-OCT is sensitive enough to image/visualize TM movement synchronous with the pulse-induced IOP transients, providing quantitative measurements of dynamic parameters such as velocity, displacement, and strain rate that are important for assessing the biomechanical compliance of the TM. We find that the largest TM displacement is in the area closest to Schlemm's canal (SC) endothelium. While maintaining constant ocular pulse amplitude, an increase of mean IOP results in a decrease of TM displacement and mean size of the SC. These results demonstrate that the PhS-OCT is a useful imaging technique capable of assessing functional properties necessary to maintain IOP in a healthy range, offering a new diagnostic alternative for glaucoma.

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Peng Li, Roberto Reif, Zhongwei Zhi, Tueng Shen, Ruikang K. Wang, Elizabeth Martin, and Murray Johnstone "Phase-sensitive optical coherence tomography characterization of pulse-induced trabecular meshwork displacement in ex vivo nonhuman primate eyes," Journal of Biomedical Optics 17(7), 076026 (24 July 2012). https://doi.org/10.1117/1.JBO.17.7.076026

Published: 24 July 2012

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