In vivo evaluation of corneal biomechanical properties by optical coherence elastography at different cross-linking irradiances

Zhou, Yuheng; Wang, Yuanyuan; Shen, Meixiao; Jin, Zi; Chen, Yihong; Zhou, Yue; Qu, Jia; Zhu, Dexi

doi:10.1117/1.jbo.24.10.105001

Cited by 31 publications

(18 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Traditionally, in vivo assessment of corneal biomechanics has been performed using dynamic wave propagation and quasistatic elastography. 18 , 20 , 39 These tools can provide important mechanical information, but often require complex analysis or additional tools to properly calculate elasticity. 40 , 41 Compared to similar methods such as compression-based OCE, the strain we see here is much lower, which is due to the much smaller displacement induced by the ocular pulse as compared to compression by a mechanical actuator.…”

Section: Resultsmentioning

confidence: 99%

Heartbeat optical coherence elastography: corneal biomechanics in vivo

et al. 2021

View full text Add to dashboard Cite

. Significance: Mechanical assessment of the cornea can provide important structural and functional information regarding its health. Current clinically available tools are limited in their efficacy at measuring corneal mechanical properties. Elastography allows for the direct estimation of mechanical properties of tissues in vivo but is generally performed using external excitation force. Aim: To show that heartbeat optical coherence elastography (Hb-OCE) can be used to assess the mechanical properties of the cornea in vivo. Approach: Hb-OCE was utilized to detect Hb-induced deformations in the rabbit cornea in vivo without the need for external excitation. Furthermore, we demonstrate how this technique can distinguish corneal stiffness between untreated (UT) and crosslinked (CXL) tissue. Results: Our results demonstrate that stiffness changes in the cornea can be detected using only the Hb-induced deformations in the cornea. Additionally, we demonstrate a statistically significant difference in strain between the UT and CXL corneas. Conclusions: Hb-OCE may be an effective tool for assessing the mechanical properties of the cornea in vivo without the need for external excitation. This tool may be effective for clinical assessment of corneal mechanical properties because it only requires optical coherence tomography imaging and data processing.

show abstract

Section: Resultsmentioning

confidence: 99%

Heartbeat optical coherence elastography: corneal biomechanics in vivo

et al. 2021

View full text Add to dashboard Cite

show abstract

“…OCE with an external excitation source has been used to assess the mechanical properties of the cornea in vivo using dynamic wave propagation methods as well as quasistatic techniques. 19,21,42 However, these techniques have a variety of limitations in acquisition and analysis, such as patient discomfort, nonlinear mechanical behavior, or lengthy imaging times. Since the technique presented in this work does not require complex wave analysis or additional tools to determine tissue mechanical properties, we can assess the mechanical properties of the cornea using only a phase-sensitive OCT system, a ubiquitous tool in ophthalmology and optometry clinics.…”

Section: Resultsmentioning

confidence: 99%

Heartbeat OCE: corneal biomechanical response to simulated heartbeat pulsation measured by optical coherence elastography

et al. 2020

View full text Add to dashboard Cite

Significance: It is generally agreed that the corneal mechanical properties are strongly linked to many eye diseases and could be used to assess disease progression and response to therapies. Elastography is the most notable method of assessing corneal mechanical properties, but it generally requires some type of external excitation to induce a measurable displacement in the tissue. Aim: We present Heartbeat Optical Coherence Elastography (Hb-OCE), a truly passive method that can measure the elasticity of the cornea based on intrinsic corneal displacements induced by the heartbeat. Approach: Hb-OCE measurements were performed in untreated and UV-A/riboflavin crosslinked porcine corneas ex vivo, and a distinct difference in strain was detected. Furthermore, a partially cross-linked cornea was also assessed, and the treated and untreated areas were similarly distinguished. Results: Our results suggest that Hb-OCE can spatially map displacements in the cornea induced by small fluctuations in intraocular pressure, similar to what is induced by the heartbeat. Conclusions: The described technique opens the possibility for completely passive and noncontact in vivo assessment of corneal stiffness.

show abstract

“…The numerical analyses estimated a 0.01 MPa shear modulus for the group of untreated corneas, and up to 0.03 MPa for the groups of treated corneas. In a subsequent work [ 32 ], using in-vivo elastography, the elastic modulus at the physiological IOP was measured as 0.09 MPa for untreated corneas and 0.14 MPa for CXL corneas irradiated at different powers.…”

Section: Discussionmentioning

confidence: 99%

Experimental in-vitro investigation on Epi-Off-Crosslinking on porcine corneas

et al. 2021

View full text Add to dashboard Cite

Aim To evaluate quantitatively the effects of the Epi-Off-CXL irradiance dose on the stromal stiffening of pig corneas. Setting Laboratory of Biological structures (LaBS), Politecnico di Milano, Milano, Italy. Methods Inflation tests have been carried on 90 excised and de-epithelized pig corneas, monitoring the change of configuration of the corneal dome at specific pressures. Test have been carried out twice on each cornea, once before and once after Epi-Off-CXL performed at a constant irradiance of 9 mW/cm2 and variable UV-A exposure times. Corneas were grouped according to the exposure time (2.5, 5, 10, 15 and 20 min), proportional to the irradiation dose (1.35, 2.7, 5.4, 8.1, and 10.8 J/cm2). A theoretical model based on linearized shell theory has been used to estimate the increment of the corneal stiffness. Results The linearized shell theory allowed to establish a quantitative relation between the increment of the stiffness parameters and the irradiation dose. Relative to the pre-treatment values, in all experiments the post-treatment corneal stiffness revealed a pronounced increase. In general, the stiffness gain increased with the exposure time. No significant differences in stiffening was observed between tests conducted at 2.5, 5, and 10 min exposure. Conclusions Qualitatively, the effectiveness of accelerated CXL treatments observed in pig corneas complies very well with in-vivo clinical results in humans, suggesting that experimental data in pigs can be very useful for the design of the procedure in humans. A larger irradiation dose provides a larger increment of the corneal stiffness. Due to the biological variability of the tissues, however, it is difficult to distinguish quantitatively the level of the reinforcement induced by accelerated protocols (low doses with < = 10 min exposure), less prone to induce damage in the corneal tissue. Therefore, the definition of personalized treatments must be related to the actual biomechanics of the cornea.

show abstract

In vivo evaluation of corneal biomechanical properties by optical coherence elastography at different cross-linking irradiances

Cited by 31 publications

References 42 publications

Heartbeat optical coherence elastography: corneal biomechanics in vivo

Heartbeat optical coherence elastography: corneal biomechanics in vivo

Heartbeat OCE: corneal biomechanical response to simulated heartbeat pulsation measured by optical coherence elastography

Experimental in-vitro investigation on Epi-Off-Crosslinking on porcine corneas

Contact Info

Product

Resources

About