March 2012
Volume 53, Issue 14
Free
ARVO Annual Meeting Abstract  |   March 2012
Impact Of Dynamically Applied Mechanical Force On Scleral Birefringence
Author Affiliations & Notes
  • Yoshiaki Yasuno
    Computational Optics Group,
    University of Tsukuba, Tsukuba, Japan
    Computational Optics and Ophthalmology Group, Tsukuba, Japan
  • Satoko Nagase
    Computational Optics and Ophthalmology Group, Tsukuba, Japan
    Dept of Ophthalmology, Tokyo Medical Univ Ibaraki Med Ctr, Ami, Japan
  • Masahiro Yamanari
    Computational Optics Group,
    University of Tsukuba, Tsukuba, Japan
    Computational Optics and Ophthalmology Group, Tsukuba, Japan
  • Kotaro Ishii
    Dept. of Ophthalmology,
    University of Tsukuba, Tsukuba, Japan
    Computational Optics and Ophthalmology Group, Tsukuba, Japan
  • Shinichi Fukuda
    Dept. of Ophthalmology,
    University of Tsukuba, Tsukuba, Japan
    Computational Optics and Ophthalmology Group, Tsukuba, Japan
  • Tetsuro Oshika
    Dept. of Ophthalmology,
    University of Tsukuba, Tsukuba, Japan
    Computational Optics and Ophthalmology Group, Tsukuba, Japan
  • Masahiro Miura
    Computational Optics and Ophthalmology Group, Tsukuba, Japan
    Dept of Ophthalmology, Tokyo Medical Univ Ibaraki Med Ctr, Ami, Japan
  • Footnotes
    Commercial Relationships  Yoshiaki Yasuno, Tomey Corp. (F, P); Satoko Nagase, None; Masahiro Yamanari, Tomey Corp. (F); Kotaro Ishii, None; Shinichi Fukuda, None; Tetsuro Oshika, Tomey Corp. (F); Masahiro Miura, None
  • Footnotes
    Support  Japan Science and Techonology Agency
Investigative Ophthalmology & Visual Science March 2012, Vol.53, 2798. doi:
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    • Get Citation

      Yoshiaki Yasuno, Satoko Nagase, Masahiro Yamanari, Kotaro Ishii, Shinichi Fukuda, Tetsuro Oshika, Masahiro Miura; Impact Of Dynamically Applied Mechanical Force On Scleral Birefringence. Invest. Ophthalmol. Vis. Sci. 2012;53(14):2798.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose: : It has been reported that birefringence of the sclera is sensitive to ultrastructure of the sclera and correlated with the elasticity. We had investigated a relationship between the scleral birefringence and its mechanical properties by using polarization-sensitive optical coherence tomography (PS-OCT) in order to make PS-OCT an early diagnostic tool for glaucoma. This previous study showed significant correlation between scleral elasticity and its birefringence at a relaxed state. However, the lack of knowledge about the scleral birefringence under mechanical force/tension limits the understanding of the mechanism behind this correlation. In this paper, we investigate how acute mechanical stress influences the scleral birefringence.

Methods: : Porcine sclera was dissected at temporal region 5-mm apart from the optic nerve head (ONH) to be a rectangular shape with a width of 4 mm. To apply one of two orthogonal extensions to each scleral sample, the long sides of the rectangular regions were oriented to meridional or its perpendicular directions. The sample was mounted on a uniaxial translation stage using two clamps that initially had 5-mm distance. Preconditioning was applied from 0 to 6.5% strain for 10 cycles of loading and unloading. Subsequently, the birefringence of the sample was measured by PS-OCT at the central 3-mm region of the sample between the clamps before and after applying stretching of 6.5% strain. Twenty and 19 porcine eyes were stretched to meridional or its perpendicular directions from the ONH, respectively.

Results: : When the sclera was stretched to the meridional direction, statistically significant increase of birefringence was found (p = 0.001, paired t-test). Averaged difference of the birefringence was +0.06 deg/um. Also with the stretch perpendicular to the meridional direction, the increase of the birefringence of +0.03 deg/um was found with statistical significance (p = 0.047).

Conclusions: : The results showed that uniaxial transversal tension does affect to the birefringence of the sclera, and this effect has bi-directionality. This bi-directionality would be associated with the orientation of collagen fibers in the sclera. This finding provides a further insight to understand the relationship between the scleral birefringence and its mechanical properties, and enhances the utility of PS-OCT as an investigation tool for glaucoma.

Keywords: sclera • stress response • optical properties 
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