Monitoring of Cornea Elastic Properties Changes during UV-A/Riboflavin-Induced Corneal Collagen Cross-Linking using Supersonic Shear Wave Imaging: A Pilot Study

Nguyen, Thu-Mai; Aubry, Jean‐François; Touboul, David; Fink, Mathias; Gennisson, Jean‐Luc; Bercoff, Jérémy; Tanter, Mickaël

doi:10.1167/iovs.11-9142

Cited by 57 publications

(46 citation statements)

References 12 publications

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“…Curve fitting of the radial profile at 310 Hz ( Fig. 5(a) [24]. To validate our observation, we performed a finite element (FE) numerical simulation [25].…”

Section: Resultsmentioning

confidence: 65%

Observation of sound-induced corneal vibrational modes by optical coherence tomography

Akca

Chang

Kling

et al. 2015

Biomed. Opt. Express

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Abstract:The mechanical stability of the cornea is critical for maintaining its normal shape and refractive function. Here, we report an observation of the mechanical resonance modes of the cornea excited by sound waves and detected by using phase-sensitive optical coherence tomography. The cornea in bovine eye globes exhibited three resonance modes in a frequency range of 50-400 Hz. The vibration amplitude of the fundamental mode at 80-120 Hz was ~8 µm at a sound pressure level of 100 dB (2 Pa). Vibrography allows the visualization of the radially symmetric profiles of the resonance modes. A dynamic finite-element analysis supports our observation. ©2015 Optical Society of America

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“…Curve fitting of the radial profile at 310 Hz ( Fig. 5(a) [24]. To validate our observation, we performed a finite element (FE) numerical simulation [25].…”

Section: Resultsmentioning

confidence: 65%

Observation of sound-induced corneal vibrational modes by optical coherence tomography

Akca

Chang

Kling

et al. 2015

Biomed. Opt. Express

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“…Previous studies on corneas using ultrasound elastography did not take into account the influence of the corneal curvature on the spatial mapping of the corneal stiffness with the Lamb wave velocity [13][14][15]. Corneal curvature could have an effect on the depthwise distribution of the Lamb wave velocity.…”

Section: Discussionmentioning

confidence: 99%

“…After getting the displacement profiles for all the transverse-depthwise positions of the cornea, a binarized two-dimensional depth-resolved OCT image is used as a mask to eliminate the spatial points with random optical phase information. Because the corneal Lamb wave propagation is guided by the surface of the cornea, similar to the ultrasound elastography of the cornea [13][14][15], the quantification of the Lamb wave phase velocity is based on the curved propagation paths that have the same curvature as the corneal surface. As the example to present our method for corneal elastography, Fig.…”

Section: Data Processingmentioning

confidence: 99%

“…Both the ultrasound elasticity microscope [12] and the supersonic shear imaging technique [13,14] are used to achieve the mapping of the depth-dependent corneal mechanical properties with the scale of tens and hundreds of microns, respectively, and very recently, in vivo applications on porcine eyes have been reported [15]. However, the relatively low axial resolution of the ultrasonic imaging and the requirement of several pixels for the calculation of the displacement or strain limit the depthwise resolving ability of these two methods.…”

Section: Introductionmentioning

confidence: 99%

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Noncontact depth-resolved micro-scale optical coherence elastography of the cornea

Wang

Larin

2014

Biomed. Opt. Express

155

129

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High-resolution elastographic assessment of the cornea can greatly assist clinical diagnosis and treatment of various ocular diseases. Here, we report on the first noncontact depth-resolved micro-scale optical coherence elastography of the cornea achieved using shear wave imaging optical coherence tomography (SWI-OCT) combined with the spectral analysis of the corneal Lamb wave propagation. This imaging method relies on a focused air-puff device to load the cornea with highly-localized lowpressure short-duration air stream and applies phase-resolved OCT detection to capture the low-amplitude deformation with nano-scale sensitivity. The SWI-OCT system is used here to image the corneal Lamb wave propagation with the frame rate the same as the OCT A-line acquisition speed. Based on the spectral analysis of the corneal temporal deformation profiles, the phase velocity of the Lamb wave is obtained at different depths for the major frequency components, which shows the depthwise distribution of the corneal stiffness related to its structural features. Our pilot experiments on ex vivo rabbit eyes demonstrate the feasibility of this method in depth-resolved micro-scale elastography of the cornea. The assessment of the Lamb wave dispersion is also presented, suggesting the potential for the quantitative measurement of corneal viscoelasticity. 3026-3031 (2007). 3. L. T. Nordan, "Keratoconus: diagnosis and treatment," Int. Ophthalmol. Clin. 37(1), 51-63 (1997). 4. C. Edmund, "Corneal elasticity and ocular rigidity in normal and keratoconic eyes," Acta Ophthalmol. (Copenh.) 66(2), 134-140 (1988 Biol. 93(1-3), 176-191 (2007). 17. G. Scarcelli and S. H. Yun, "Confocal Brillouin microscopy for three-dimensional mechanical imaging," Nat. ©2014 Optical Society of AmericaPhotonics 2(1), 39-43 (2008). 18. J. Schmitt, "OCT elastography: imaging microscopic deformation and strain of tissue," Opt. Express 3(6), 199-211 (1998). 19. G. Scarcelli and S. H. Yun, "In vivo Brillouin optical microscopy of the human eye," Opt. Express 20(8), 9197-9202 (2012). 20. G. Scarcelli, R. Pineda, and S. H. Yun, "Brillouin optical microscopy for corneal biomechanics," Invest.Ophthalmol. Vis. Sci. 53(1), 185-190 (2012). 21. G. Scarcelli, S. Kling, E. Quijano, R. Pineda, S. Marcos, and S. H. Yun, "Brillouin microscopy of collagen crosslinking: noncontact depth-dependent analysis of corneal elastic modulus," Invest. Ophthalmol. Vis. Sci.

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“…4 OCE is similar to other elastographic techniques such as ultrasound elastography (USE), 5 magnetic resonance elastography (MRE), 6 and supersonic shear wave imaging (SSI) [7][8][9] where an externally induced deformation is measured by the respective imaging modality. OCE has micrometer scale spatial resolution 10 and millisecond temporal resolution but has a limited penetration depth of a few millimeters in scattering media such as tissue.…”

mentioning

confidence: 99%

Analysis of the effects of curvature and thickness on elastic wave velocity in cornea-like structures by finite element modeling and optical coherence elastography

Han

Singh

et al. 2015

Applied Physics Letters

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Wave models that have been used to extract the biomechanical properties of the cornea from the propagation of an elastic wave are based on an assumption of thin-plate geometry. However, this assumption does not account for the effects of corneal curvature and thickness. This study conducts finite element (FE) simulations on four types of cornea-like structures as well as optical coherence elastography (OCE) experiments on contact lenses and tissue-mimicking phantoms to investigate the effects of curvature and thickness on the group velocity of an elastic wave. The elastic wave velocity as determined by FE simulations and OCE of a spherical shell section decreased from $2.8 m/s to $2.2 m/s as the radius of curvature increased from 19.1 mm to 47.7 mm and increased from $3.0 m/s to $4.1 m/s as the thickness of the agar phantom increased from 1.9 mm to 5.6 mm. Both the FE simulation and OCE results confirm that the group velocity of the elastic wave decreases with radius of curvature but increases with thickness. These results demonstrate that the effects of the curvature and thickness must be considered in the further development of accurate wave models for reconstructing biomechanical properties of the cornea. Assessing the biomechanical properties of the cornea is of great importance for detecting and monitoring the progression of ocular diseases, such as keratoconus, as well as evaluating the effectiveness of therapies, such as UVinduced collagen cross-linking. 1 In recent years, a number of noninvasive techniques have been proposed to characterize corneal biomechanical properties. For instance, the CorVis can image corneal dynamic responses from a strong air-puff stimulation, 2 and Brillouin microscopy is able to show the depth-resolved Brillouin frequency shift distribution of the cornea.3 Although these methods can provide important measurements that reflect the biomechanical characteristics of the cornea, directly quantifying the viscoelasticity of the cornea by these techniques is still a challenge.Optical coherence elastography (OCE) is a rapidly emerging method that can noninvasively measure the local biomechanical properties of tissues.4 OCE is similar to other elastographic techniques such as ultrasound elastography (USE), 5 magnetic resonance elastography (MRE), 6 and supersonic shear wave imaging (SSI) 7-9 where an externally induced deformation is measured by the respective imaging modality. OCE has micrometer scale spatial resolution 10 and millisecond temporal resolution but has a limited penetration depth of a few millimeters in scattering media such as tissue. However, penetration depth is not an issue for corneal imaging, and thus, OCE is specifically suitable for obtaining the biomechanical properties of the cornea. In our previous work, an OCE system comprised of an external noncontact loading device and an optical coherence tomography (OCT) system was utilized for tumor detection, 11 lens, 12 cornea, 13 cartilage, 14 and cardiac muscle 15 elasticity estimations. Although we have utilized a fo...

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Monitoring of Cornea Elastic Properties Changes during UV-A/Riboflavin-Induced Corneal Collagen Cross-Linking using Supersonic Shear Wave Imaging: A Pilot Study

Abstract: The in vivo CXL experiments performed on pigs demonstrated that the quantitative estimation of local stiffness and the 2-D elastic maps of the corneal surface provide an efficient way to monitor the local efficacy of corneal cross-linking.

Cited by 57 publications

References 12 publications

Observation of sound-induced corneal vibrational modes by optical coherence tomography

Observation of sound-induced corneal vibrational modes by optical coherence tomography

Noncontact depth-resolved micro-scale optical coherence elastography of the cornea

Analysis of the effects of curvature and thickness on elastic wave velocity in cornea-like structures by finite element modeling and optical coherence elastography

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