Intraocular Pressure–dependent Corneal Elasticity Measurement Using High-frequency Ultrasound

Osapoetra, Laurentius O.; Watson, D. M.; McAleavey, Stephen A.

doi:10.1177/0161734619858386

Cited by 12 publications

(6 citation statements)

References 44 publications

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“…There is well-documented evidence suggesting that IOP correlates with stiffness. [50][51][52][53][54] One limitation of this work is that IOP effects on the cornea have not been investigated. Changes in the baseline IOP, as well as the accuracy of IOP measurements, may affect the Hb-OCE measured stiffness.…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2020

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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.

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Section: Discussionmentioning

confidence: 99%

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

et al. 2020

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“…12 The accessibility and small imaging depth of the cornea lends itself to the unique opportunities for very highfrequency ultrasound (i.e., ≥50 MHz) imaging 13,14 and elastography. [15][16][17] Moreover, the pressure inside the eye (the intraocular pressure [IOP]) fluctuates between the diastolic (baseline) and systolic (baseline + ocular pulse) pressures at each heart beat. Using these intrinsic loading and unloading cycles, we aim to develop a high-frequency ultrasound elastography method to characterize the cornea's response to the ocular pulse, termed the ocular pulse elastography (OPE) technique.…”

Section: Introductionmentioning

confidence: 99%

Ocular Pulse Elastography: Imaging Corneal Biomechanical Responses to Simulated Ocular Pulse Using Ultrasound

Clayson

Pavlatos

Pan

et al. 2020

Trans. Vis. Sci. Tech.

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In vivo evaluation of corneal biomechanics holds the potential for improving diagnosis and management of ocular diseases. We aimed to develop an ocular pulse elastography (OPE) technique to quantify corneal strains generated by naturally occurring pulsations of the intraocular pressure (IOP) using high-frequency ultrasound. Methods: Simulated ocular pulses were induced in whole porcine and human donor globes to investigate the effects of physiologic variations in baseline IOP, ocular pulse amplitude, and frequency on corneal strains. Ocular pulse-induced strains were measured in additional globes before and after UVA-riboflavin-induced corneal crosslinking. The central cornea in each eye was imaged with a 50-MHz ultrasound imaging system and correlation-based speckle tracking of radiofrequency data was used to calculate tissue displacements and strains. Results: Ocular pulse-induced corneal strains followed the cyclic changes of IOP. Both baseline IOP and ocular pulse amplitude had a significant influence on strain magnitude. Variations in pulse frequency within the normal human heart rate range did not introduce detectable changes in corneal strains. A significant decrease of corneal strain, as quantified by the OPE technique, was observed after corneal crosslinking. The extent of corneal stiffening (i.e., strain reduction) seemed to correlate with the initial strain magnitude. Conclusions: This ex vivo study demonstrated the feasibility of the OPE method to quantify corneal strains generated by IOP pulsation and detect changes associated with corneal crosslinking treatment. Translational Relevance: Integrating in vivo measurement of IOP and ocular pulse amplitude, the OPE method may lead to a new clinical tool for safe and quick biomechanical evaluations of the cornea.

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“…Through the multi‐level model, the corneal elasticity is found to have a strong linear correlation with IOP for each eye, which has also been confirmed in vitro studies. [31, 32] The slopes of the lines in the Figure 6 is stable for the same individual. Thus, we propose a new indicator, namely corneal elasticity change rate, presents the magnitude of corneal elasticity change caused by 1 mmHg IOP.…”

Section: Discussionmentioning

confidence: 91%

Diurnal variation of corneal elasticity in healthy young human using air‐puff optical coherence elastography

Chen

Jin

et al. 2021

Journal of Biophotonics

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Due to the disruption of intraocular pressure (IOP) and central corneal thickness (CCT), diurnal variation in normal young human corneal elasticity is not clear. Using the custom‐built air‐puff optical coherence elastography, one eye of 21 normal subjects is enrolled randomly to measure the central corneal elasticity, IOP, and CCT in different time points within a day. Based on the multi‐level model, the corneal elastic modulus is found to have a linear positive relation with IOP (P < .01) but not CCT (P = .175) and time point (P = .174–.686). A new indicator, corneal elasticity change rate, is proposed to present the magnitude of corneal elasticity change caused by 1 mmHg IOP, which can correct the interference effect of IOP. The results show that the corneal elasticity in the normal young human does not have the characteristics of diurnal variation under IOP control. Furthermore, IOP plays an important role in the corneal elasticity, and corneal elasticity change rate can increase the comparability of results between individuals.

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Intraocular Pressure–dependent Corneal Elasticity Measurement Using High-frequency Ultrasound

Cited by 12 publications

References 44 publications

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

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

Ocular Pulse Elastography: Imaging Corneal Biomechanical Responses to Simulated Ocular Pulse Using Ultrasound

Diurnal variation of corneal elasticity in healthy young human using air‐puff optical coherence elastography

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