Assessing Porcine Iris Elasticity and Mechanical Anisotropy with Optical Coherence Elastography

Zevallos-Delgado, Christian; Mekonnen, Taye; Zvietcovich, Fernando; Singh, Manmohan; Aglyamov, Salavat R.; Larin, Kirill V.

doi:10.18287/jbpe21.07.040304

Cited by 8 publications

(8 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…11,14,26,27 The elastic wave speeds in the various components of the eye fall within a reasonable range as reported in previous studies. 11,15,26,28 However, it is worth noting that these values may significantly differ depending on factors such as the IOP, boundary conditions, species, and age of the animal model. 15,[28][29][30] The technique also allowed for the evaluation of localized elastic wave speed within specific ocular components.…”

Section: Discussionsupporting

confidence: 87%

“…Although the posterior sclera had a relatively lower speed compared to the anterior sclera, this difference was not found to be statistically significant (p>0.05). If the IOP were maintained at a higher level (≥12 mmHg), it is possible that the contrast in wave speed between the cornea, lens, and iris would have been even more pronounced 11 , 14 , 26 , 27 . The elastic wave speeds in the various components of the eye fall within a reasonable range as reported in previous studies 11 , 15 , 26 , 28 .…”

Section: Discussionsupporting

confidence: 55%

“…If the IOP were maintained at a higher level (≥12 mmHg), it is possible that the contrast in wave speed between the cornea, lens, and iris would have been even more pronounced 11 , 14 , 26 , 27 . The elastic wave speeds in the various components of the eye fall within a reasonable range as reported in previous studies 11 , 15 , 26 , 28 . However, it is worth noting that these values may significantly differ depending on factors such as the IOP, boundary conditions, species, and age of the animal model 15 , 28 …”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Multifocal acoustic radiation force-based reverberant optical coherence elastography for evaluation of ocular globe biomechanical properties

Mekonnen,

Zevallos-Delgado,

Singh

et al. 2023

J. Biomed. Opt.

Self Cite

View full text Add to dashboard Cite

Quantifying the biomechanical properties of the whole eye globe can provide a comprehensive understanding of the interactions among interconnected ocular components during dynamic physiological processes. By doing so, clinicians and researchers can gain valuable insights into the mechanisms underlying ocular diseases, such as glaucoma, and design interventions tailored to each patient's unique needs. Aim:The aim of this study was to evaluate the feasibility and effectiveness of a multifocal acoustic radiation force (ARF) based reverberant optical coherence elastography (RevOCE) technique for quantifying shear wave speeds in different ocular components simultaneously.Approach: We implemented a multifocal ARF technique to generate reverberant shear wave fields, which were then detected using phase-sensitive optical coherence tomography. A 3D-printed acoustic lens array was employed to manipulate a collimated ARF beam generated by an ultrasound transducer, producing multiple focused ARF beams on mouse eye globes ex vivo. RevOCE measurements were conducted using an excitation pulse train consisting of 10 cycles at 3 kHz, followed by data processing to produce a volumetric map of the shear wave speed. Results:The results show that the system can successfully generate reverberant shear wave fields in the eye globe, allowing for simultaneous estimation of shear wave speeds in various ocular components, including cornea, iris, lens, sclera, and retina. A comparative analysis revealed notable differences in wave speeds between different parts of the eye, for example, between the apical region of the cornea and the pupillary zone of the iris (p ¼ 0.003). Moreover, the study also revealed regional variations in the biomechanical properties of ocular components as evidenced by greater wave speeds near the apex of the cornea compared to its periphery. Conclusions:The study demonstrated the effectiveness of RevOCE based on a non-invasive multifocal ARF for assessing the biomechanical properties of the whole eyeball. The findings indicate the potential to provide a comprehensive understanding of the mechanical behavior of the whole eye, which could lead to improved diagnosis and treatment of ocular diseases.

show abstract

Section: Discussionsupporting

confidence: 87%

Section: Discussionsupporting

confidence: 55%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Multifocal acoustic radiation force-based reverberant optical coherence elastography for evaluation of ocular globe biomechanical properties

Mekonnen,

Zevallos-Delgado,

Singh

et al. 2023

J. Biomed. Opt.

Self Cite

View full text Add to dashboard Cite

show abstract

“…optical coherence tomography (OCT) [29]) and elastography techniques (e.g. optical coherence elastography (OCE) [30,31]) to complement the NiR imaging-based technique presented herein. Further, due to the two-dimensional nature of our data, our model could not uniquely evaluate the iridial Poisson's ratio.…”

Section: Discussionmentioning

confidence: 99%

In vivobiomechanical assessment of iridial deformations and muscle contractions in human eyes

Safa

Fard

Ethier

2022

J. R. Soc. Interface.

View full text Add to dashboard Cite

The iris is a muscular organ whose deformations can cause primary angle-closure glaucoma (PACG), a leading cause of blindness. PACG risk assessment does not consider iridial biomechanical factors, despite their expected influence on iris deformations. Here, we exploited an existing biometric dataset consisting of near-infrared movies acquired during the pupillary light reflex (PLR) as a unique resource to study iris biomechanics. The PLR caused significant (greater than 100%) and essentially spatially uniform radial strains in the iris in vivo , consistent with previous findings. Inverse finite-element modelling showed that sphincter muscle tractions were ca fivefold greater than iridial stroma stiffness (range 4- to 13-fold, depending on sphincter muscle size). This muscle traction is greater than has been previously estimated, which may be due to methodological differences and/or to different patient populations in our study (European descent) versus previous studies (Asian); the latter possibility is of particular interest due to differential incidence rates of PACG in these populations. Our methodology is fast and inexpensive and may be a useful tool in understanding biomechanical factors contributing to PACG.

show abstract

“…Prior studies of iridial biomechanical properties using OCE demonstrated promising outcomes for reconstruction of iris elasticity and mechanical anisotropy. 15,16…”

Section: Introductionmentioning

confidence: 99%

Characterizing regional biomechanical properties of the porcine iris using optical coherence elastography

Mekonnen

Delgado²,

Safa³

et al. 2023

Optical Elastography and Tissue Biomechanics X

Self Cite

View full text Add to dashboard Cite

The fundamental physiological function of the iris is to control the amount of light entering the eye, which requires the coordinated constriction or dilation of the pupil, affected by two antagonistic muscles, namely the sphincter and radial muscles. Disorders of the iris, including these muscles, may lead to ocular pathologies, such as primary angle-closure glaucoma. Here, we assessed the regional biomechanical properties of the iris using phase-sensitive optical coherence elastography (PhS-OCE) to quantify the shear wave speed arising from perturbations generated using an acoustic radiation force (ARF) transducer of resonant frequency 3.5 MHz and focal length 19 mm. We determined regional shear wave speeds by tracking elastic wave propagation in ex vivo porcine irides. Results showed that the mean shear wave speed in the pupillary zone (~2.1 m/s) was consistently greater than in the ciliary zone (~1.87 m/s). These findings indicate that the mechanical properties of the iris exhibit regional heterogeneity, which may be related to the microstructure of the iris (muscle locations/extent) and intrinsic elastic properties.

show abstract

Assessing Porcine Iris Elasticity and Mechanical Anisotropy with Optical Coherence Elastography

Cited by 8 publications

References 39 publications

Multifocal acoustic radiation force-based reverberant optical coherence elastography for evaluation of ocular globe biomechanical properties

Multifocal acoustic radiation force-based reverberant optical coherence elastography for evaluation of ocular globe biomechanical properties

In vivobiomechanical assessment of iridial deformations and muscle contractions in human eyes

Characterizing regional biomechanical properties of the porcine iris using optical coherence elastography

Contact Info

Product

Resources

About