June 2017
Volume 58, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2017
Quantitative-ultrasound assessment of the myopic sclera in the guinea pig
Author Affiliations & Notes
  • Jonathan Mamou
    Lizzi Ctr for Biomedical Engineering, Riverside Research, New York, New York, United States
  • Ronald H Silverman
    Department of Ophthalmology, Columbia University Medical Center, New York, New York, United States
  • Sally A McFadden
    Vision Sciences Group, Faculty of Science and IT, School of Psychology, University of Newcastle, Newcastle, New South Wales, Australia
  • Quan V Hoang
    Department of Ophthalmology, Columbia University Medical Center, New York, New York, United States
    Singapore Eye Research Institute, Singapore National Eye Centre, Singapore, Singapore
  • Footnotes
    Commercial Relationships   Jonathan Mamou, None; Ronald Silverman, None; Sally McFadden, None; Quan Hoang, None
  • Footnotes
    Support  This work was supported in part by an unrestricted grant from Research to Prevent Blindness (RPB), NIH Core Grant P30EY019007, NIH Grant R21EB016117 (JM), Hunter Medical Research Institute HMRI G1400967 (SAM) and Career Development Awards from Research to Prevent Blindness (QVH), K08 Grant (QVH, 1 K08 EY023595, National Eye Institute, NIH) and philanthropic support from Joseph Connors (QVH).
Investigative Ophthalmology & Visual Science June 2017, Vol.58, 4426. doi:
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    • Get Citation

      Jonathan Mamou, Ronald H Silverman, Sally A McFadden, Quan V Hoang; Quantitative-ultrasound assessment of the myopic sclera in the guinea pig. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4426.

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

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Abstract

Purpose : Quantitative ultrasound (QUS) permits estimation of QUS parameters associated with tissue microstructure and organization. In this study, QUS parameters were obtained using 80-MHz ultrasound (US) images from the posterior sclera in myopic guinea pigs (GPs). We hypothesize that QUS may provide a new and quantitative contrast mechanism that could ultimately assess ocular biomechanical properties in vivo.

Methods : US radiofrequency data were collected using a broadband 80-MHz transducer (Figs. 1a,b) from both eyes of GPs that had undergone form deprivation in the right eye (5-20 days). Intact, normotensive eyes were immersed, “levitated” in Dulbecco's phosphate buffered saline and anchored in a nearly in vivo anatomic position with partial thickness corneal sutures (Fig. 1c). With the transducer aimed at the posterior pole of the eye, a 2D scan centered at the optic nerve was acquired and the data were processed to derive several QUS parameters.

Results : Figure 1d depicts results obtained from an animal that had -7.24D of induced relative myopia (left +6.72D, right -0.52D). Specifically, it shows conventional US images augmented with color-coded information corresponding to the value of the effective scatterer diameter (ESD), which is a QUS parameter providing the effective size of the structures responsible for US scattering. A striking quantitative contrast is visible, with ESD values lower in the myopic right eye (9.0 +\- 0.50 µm) than in the contralateral control eye (10.4 +\- 0.50 µm, t-test, p<0.0001).

Conclusions : This study establishes that QUS methods may be sensitive to changes occurring in the posterior sclera during myopia. For example, US scattering could be dominated by collagen fibrils and QUS methods and ESD could potentially be sensitive to these structural changes. QUS may provide a new means of quantitatively assessing myopia progression, severity, and treatment efficacy.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

 

Figure 1: a) Photograph of the 80-MHz QUS experiments, b) 80-MHz transducer above the posterior eye surface, and c) eye “levitating” in solution with the sclera essentially under zero tension, mimicking in vivo conditions. QUS images obtained from the control (d, bottom) and myopic (d, top) eyes. The color-coded information is the effective scatterer diameter, which shows contrast between thy myopic and control eyes.

Figure 1: a) Photograph of the 80-MHz QUS experiments, b) 80-MHz transducer above the posterior eye surface, and c) eye “levitating” in solution with the sclera essentially under zero tension, mimicking in vivo conditions. QUS images obtained from the control (d, bottom) and myopic (d, top) eyes. The color-coded information is the effective scatterer diameter, which shows contrast between thy myopic and control eyes.

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