著者

Nagase Satoko Yamanari Masahiro Tanaka Ryosuke Yasui Takeshi Miura Masahiro Iwasaki Takuya Goto Hiroshi Yasuno Yoshiaki

出版者

Public Library of Science

雑誌

PLoS ONE (ISSN:19326203)

巻号頁・発行日

vol.8, no.3, pp.e58716, 2013-03

被引用文献数

13 5

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PurposeTo investigate the relationship between scleral mechanical properties, its birefringence, and the anisotropy of birefringence alteration in respect of the direction of the strain by using PS-OCT.MethodsThe scleral birefringence of thirty-nine porcine eyes was measured with a prototype PS-OCT. A rectangle strip of sclera with a width of 4 mm was dissected at the temporal region 5 mm apart from the optic nerve head. The strain and force were measured with a uniaxial tension tester as the sample was stretched with a speed of 1.8 mm/min after preconditioning. The birefringence of the sample was measured by PS-OCT at the center of the sample before applying, denoted as inherent birefringence, and after applying stretching of 6.5% strain. The birefringence alteration was obtained by these two measurements and correlations between birefringence and elastic parameters, tangent modulus, and structural stiffness were examined. Twenty and 19 porcine eyes were stretched in meridional or equatorial directions, respectively.ResultsA moderate positive correlation was found between the inherent birefringence and the structural stiffness. A moderate positive correlation was also found between the inherent birefringence and the tangent modulus. The birefringence increased by strains. Marginal significance was found in the birefringence alteration between meridional and equatorial strains, where the mean birefringence elevation by meridional strain was higher than that by equatorial strain.ConclusionsThe birefringence was found to be altered by applying strain and also be related with inherent birefringence. This implies the birefringence of the sclera of the in vivo eye also could be affected by its mechanical property.Citation: Nagase S, Yamanari M, Tanaka R, Yasui T, Miura M, et al. (2013) Anisotropic Alteration of Scleral Birefringence to Uniaxial Mechanical Strain. PLoS ONE 8(3): e58716. doi:10.1371/journal.pone.0058716Editor: Laurent Kreplak, Dalhousie University, CanadaReceived: October 30, 2012; Accepted: February 5, 2013; Published: March 11, 2013Copyright: © 2013 Nagase et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Funding: Financial support for this study was provided in part by Japan Science Technology Agency. YY had financial interest in Tomey Corp. MY is an employee of Tomey Corp. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Competing interests: The authors have read the journal's policy and have the following conflicts: Yasuno and Yamanari are supported by a research grant from Tomey Corp. through their institution. Yamanari is now employee of Tomey Corporation. This does not alter the authors' adherence to all the PLOS ONE policies on sharing data and materials.

著者

Makita Shuichi Jaillon Franck Yamanari Masahiro Yasuno Yoshiaki

出版者

Optical Society of America

雑誌

Optics Express (ISSN:10944087)

巻号頁・発行日

vol.30, no.2, pp.2681-2692, 2012-01

被引用文献数

6 3

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Dual-beam-scan Doppler optical coherence angiography (DB-OCA) enables high-speed, high-sensitivity blood flow imaging. However, birefringence of biological tissues is an obstacle to vasculature imaging. Here, the influence of polarization and birefringence on DB-OCA imaging was analyzed. A DB-OCA system without birefringence artifact has been developed by introducing a Faraday rotator. The performance was confirmed in vitro using chicken muscle and in vivo using the human eye. Birefringence artifacts due to birefringent tissues were suppressed. Micro-vasculatures in the lamina cribrosa and nerve fiber layer of human eyes were visualized in vivo. High-speed and high-sensitivity micro-vasculature imaging involving birefringent tissues is available with polarization multiplexing DB-OCA.

著者

Yamanari Masahiro Ishii Kotaro Fukuda Shinichi Lim Yiheng Duan Lian Makita Shuichi Miura Masahiro Oshika Tetsuro Yasuno Yoshiaki

出版者

Public Library of Science

雑誌

PLoS ONE (ISSN:19326203)

巻号頁・発行日

vol.7, no.9, pp.e44026, 2012-09

被引用文献数

26 5

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PurposeTo investigate a relationship between birefringence and elasticity of porcine sclera ex vivo using polarization-sensitive optical coherence tomography (PS-OCT).MethodsElastic parameters and birefringence of 19 porcine eyes were measured. Four pieces of scleral strips which were parallel to the limbus, with a width of 4 mm, were dissected from the optic nerve head to the temporal side of each porcine eye. Birefringence of the sclera was measured with a prototype PS-OCT. The strain and force were measured with a uniaxial material tester as the sample was stretched with a speed of 1.8 mm/min after preconditioning. A derivative of the exponentially-fitted stress-strain curve at 0% strain was extracted as the tangent modulus. Power of exponential stress-strain function was also extracted from the fitting. To consider a net stiffness of sclera, structural stiffness was calculated as a product of tangent modulus and thickness. Correlations between birefringence and these elastic parameters were examined.ResultsStatistically significant correlations between birefringence and all of the elastic parameters were found at 2 central positions. Structural stiffness and power of exponential stress-strain function were correlated with birefringence at the position near the optic nerve head. No correlation was found at the position near the equator.ConclusionsThe evidence of correlations between birefringence and elasticity of sclera tested uniaxially was shown for the first time. This work may become a basis for in vivo measurement of scleral biomechanics using PS-OCT.