High-speed OCT-based ocular biometer combined with an air-puff system for determination of induced retraction-free eye dynamics

Jimenez-Villar, Alfonso; Mączyńska, Ewa; Cichański, Artur; Wojtkowski, Maciej; Kałużny, Bartłomiej J.; Grulkowski, Ireneusz

doi:10.1364/boe.10.003663

Cited by 24 publications

(8 citation statements)

References 42 publications

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“…Wave-based OCE techniques are the most common form of dynamic OCE techniques, and thus has been used extensively to study ocular tissues [14,18]. Specifically for the lens, OCT enabled in vivo monitoring of the lens response to mechanical stimulus like an air puff with long-range OCT biometry [20]. OCE has also been used to measure strain dynamics for corneal reshaping [21], irradiation induced tissue dilation [22], and localized irradiation strain in crosslinked corneas [23].…”

Section: Introductionmentioning

confidence: 99%

Multimodal quantitative optical elastography of the crystalline lens with optical coherence elastography and Brillouin microscopy

Ambekar¹,

Singh²,

Zhang³

et al. 2020

Biomed. Opt. Express

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Assessing the biomechanical properties of the crystalline lens can provide crucial information for diagnosing disease and guiding precision therapeutic interventions. Existing noninvasive methods have been limited to global measurements. Here, we demonstrate the quantitative assessment of the elasticity of crystalline lens with a multimodal optical elastography technique, which combines dynamic wave-based optical coherence elastography (OCE) and Brillouin microscopy to overcome the drawbacks of individual modalities. OCE can provide direct measurements of tissue elasticity rapidly and quantitatively, but it is a challenge to image transparent samples such as the lens because this technique relies on backscattered light. On the other hand, Brillouin microscopy can map the longitudinal modulus with micro-scale resolution in transparent samples. However, the relationship between Brillouin-deduced modulus and Young's modulus is not straightforward and sample dependent. By combining these two techniques, we can calibrate Brillouin measurements with OCE, based on the same sample, allowing us to completely map the Young's modulus of the crystalline lens. The combined system was first validated with tissue-mimicking gelatin phantoms of varying elasticities (N = 9). The OCE data was used to calibrate the Brillouin shift measurements and subsequently map the Young's modulus of the phantoms. After validation, OCE and Brillouin measurements were performed on ex-vivo porcine lenses (N = 6), and the Young's modulus of the lenses was spatially mapped. The results show a strong correlation between Young's moduli measured by OCE and longitudinal moduli measured by Brillouin microscopy. The correlation coefficient R was 0.98 for the phantoms and 0.94 for the lenses, respectively. The mean Young's modulus of the anterior and posterior lens was 1.98 ± 0.74 kPa and 2.93 ± 1.13 kPa, respectively, and the Young's modulus of the lens nucleus was 11.90 ± 2.94 kPa. The results presented in this manuscript open a new way for truly quantitative biomechanical mapping of optically transparent (or low scattering) tissues in 3D.

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Section: Introductionmentioning

confidence: 99%

Multimodal quantitative optical elastography of the crystalline lens with optical coherence elastography and Brillouin microscopy

Ambekar¹,

Singh²,

Zhang³

et al. 2020

Biomed. Opt. Express

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“…The other possible drawback of the study is the fact that we based only on the commercially available devices. However, scientific research is carried out on OCT devices to record the reaction of eye structures to a blast of air [ 31 ]. Possibly, the parameters related to corneal buckling could also be determined with this newly developed device.…”

Section: Discussionmentioning

confidence: 99%

Novel Method of Measuring Corneal Viscoelasticity Using the Corvis ST Tonometer

Boszczyk

Kasprzak

Przeździecka-Dołyk

2022

JCM

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Background: The process of rapid propagation of the corneal deformation in air puff tonometer depends not only on intraocular pressure, but also on the biomechanical properties of the cornea and anterior eye. One of the biomechanical properties of the cornea is viscoelasticity, which is the most visible in its high-speed deformations. It seems reasonable to link the corneal viscoelasticity parameter to two moments of the highest speed of corneal deformations, when the cornea buckles. The aim of this work is to present a method of determining the time and place of occurrence of corneal buckling, examine spatial and temporal dependencies between two corneal applanations and bucklings in the Corvis ST tonometer, and correlate these dependencies with corneal viscoelastic properties. Methods: Images of the horizontal cross section of the Corvis ST deformed cornea from the air puff tonometer Corvis ST were used. 14 volunteers participated in the study, each of them had one eye measured eight times. Mutual changes in the profile slopes of the deformed corneas were numerically determined. They describe pure corneal deformation, eliminating the influence of rotation, and displacement of the entire eyeball. For each point in the central area of the corneal profile, the maximum velocities of mutual slope changes accompanying the applanations were estimated. The times of their occurrence were adopted as buckling times. Results: The propagation of buckling along the corneal profile is presented, as well as the repeatability and mutual correlations between the buckling parameters and intraocular pressure. Based on the relationship between them, a new parameter describing corneal hysteresis: Corvis Viscoelasticity (CVE) is introduced. It is characterized by high repeatability: ICC = 0.82 (0.69–0.93 CI) and low and insignificant correlation with intraocular pressure: r = 0.25 (p-value = 0.38). Conclusion: The results show for the first time how to measure the corneal buckling and viscoelastic effects with Corvis ST. CVE is a new proposed biomechanical parameter related to the viscoelastic properties of the cornea, which has high repeatability for the examined subject. The distribution of its values is planned to be tested on different groups of patients in order to investigate its clinical applicability.

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“…Among three methods, elastic wave measurement is most frequently used because the vibrational amplitude comparison just acquires the relative elasticity and the process of the resonant frequency measurement is complex . The elastic wave is induced by the excitation mechanisms, including piezoelectric transducer (PZT) , air‐puff device , and acoustic radiation force , and its velocity is proved to be related to the elastic modulus of soft tissue in almost studies.…”

Section: Introductionmentioning

confidence: 99%

Assessment of corneal viscoelasticity using elastic wave optical coherence elastography

Jin

Zhou

Shen

et al. 2019

Journal of Biophotonics

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The corneal viscoelasticity have great clinical significance, such as the early diagnosis of keratoconus. In this work, an analysis method which utilized the elastic wave velocity, frequency and energy attenuation to assess the corneal viscoelasticity is presented. Using phase‐resolved optical coherence tomography, the spatial‐temporal displacement map is derived. The phase velocity dispersion curve and center frequency are obtained by transforming the displacement map into the wavenumber‐frequency domain through the 2D fast Fourier transform (FFT). The shear modulus is calculated through Rayleigh wave equation using the phase velocity in the high frequency. The normalized energy distribution is plotted by transforming the displacement map into the spatial‐frequency domain through the 1D FFT. The energy attenuation coefficient is derived by exponential fitting to calculate the viscous modulus. Different concentrations of tissue‐mimicking phantoms and porcine corneas are imaged to validate this method, which demonstrates that the method has the capability to assess the corneal viscoelasticity.

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High-speed OCT-based ocular biometer combined with an air-puff system for determination of induced retraction-free eye dynamics

Cited by 24 publications

References 42 publications

Multimodal quantitative optical elastography of the crystalline lens with optical coherence elastography and Brillouin microscopy

Multimodal quantitative optical elastography of the crystalline lens with optical coherence elastography and Brillouin microscopy

Novel Method of Measuring Corneal Viscoelasticity Using the Corvis ST Tonometer

Assessment of corneal viscoelasticity using elastic wave optical coherence elastography

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