In vivo estimation of murine iris stiffness using finite element modeling

Lee, Chanyoung; Li, Guorong; Stamer, W. Daniel; Ethier, C. Ross

doi:10.1016/j.exer.2020.108374

Cited by 10 publications

(16 citation statements)

References 35 publications

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“…The in vivo stiffness of a healthy iris in our study was found to be 17.1 ± 6.6 kPa with 40 kPa of applied active stress. In a recent study, Lee et al 29 estimated the murine iris stiffness to be 96.1 ± 54.7 kPa following an in vivo protocol. The in vivo iris stiffness of human subjects reported by Pant et al 9 was 38.8 ± 15.8 kPa with 40 kPa of active stress.…”

Section: Discussionmentioning

confidence: 99%

Changes in Iris Stiffness and Permeability in Primary Angle Closure Glaucoma

Panda

Tan

Tun

et al. 2021

Invest. Ophthalmol. Vis. Sci.

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Section: Discussionmentioning

confidence: 99%

Changes in Iris Stiffness and Permeability in Primary Angle Closure Glaucoma

Panda

Tan

Tun

et al. 2021

Invest. Ophthalmol. Vis. Sci.

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“…Also, prior studies have reported the existence of rotational and translational movements of the iris during changes of IOP inside the eye. These movements could cause variations in the biomechanical properties of the iris [9]. To our knowledge, previous OCE methods used to analyze the iris biomechanics did not investigate possible stiffness variations caused by IOP changes [11,16].…”

Section: Introductionmentioning

confidence: 95%

“…The iris can suffer several lesions and can be altered by diseases such as glaucoma, uveitis, cancer, and physical trauma [5][6][7]. These lesions can cause severe morphological changes to the iris structure and modify its biomechanical properties [8,9]. The iris structure can also be altered by drugs which can modify the normal miosis and mydriasis of the iris [10].…”

Section: Introductionmentioning

confidence: 99%

“…In addition to abnormal morphological changes, the iris also undergoes natural variations due to its function in the eye (contraction and expansion) [11]. Several studies have shown interest in determining the biomechanical properties of the iris, under different conditions (in vivo or ex vivo) using animal models [12][13][14] or human volunteers [11], using different techniques such as Atomic Force Microscopy (AFM) [15], Optical Coherence Tomography (OCT) [9], and Optical Coherence Elastography (OCE) [11,14,16]. Although AFM showed a high capacity to determine the stiffness of the iris, it had several limitations.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Assessing Porcine Iris Elasticity and Mechanical Anisotropy with Optical Coherence Elastography

Zevallos-Delgado

Mekonnen

Zvietcovich

et al. 2021

J-BPE

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“…The in-vivo stiffness of a healthy iris in our study was found to be 17.1±6.6 kPa with 40 kPa of applied active stress. In a recent study, Lee et al estimated the murine iris stiffness to be 96.1±54.7 kPa following an in-vivo protocol [26]. The in-vivo iris stiffness of human subjects reported by Pant et al was 38.8±15.8 kPa with 40 kPa of active stress.…”

Section: Higher Tissue Stiffness In Pacg Subjectsmentioning

confidence: 98%

Changes in Iris Stiffness and Permeability in Primary Angle Closure Glaucoma

Panda

Tan

Tun

et al. 2021

Preprint

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PurposeTo evaluate the biomechanical properties of the iris by evaluating iris movement during pupil constriction and to compare such properties between healthy and primary angle-closure glaucoma (PACG) subjects.MethodsA total of 140 subjects were recruited for this study. In a dark room, the anterior segments of one eye per subject were scanned using anterior segment optical coherence tomography (AS-OCT, SS-1000 CASIA, Tomey Corporation, Nagoya, Japan) imaging during induced pupil constriction with an external white light source of 1700 lux. Using a custom segmentation code, we automatically isolated the iris segments from the AS-OCT images, which were then discretized and transformed into a three-dimensional point cloud. For each iris, a finite element (FE) mesh was constructed from the point cloud, and an inverse FE simulation was performed to match the clinically observed iris constriction in the AS-OCT images. Through this optimization process, we were able to identify the elastic modulus and permeability of each iris.ResultsFor all 140 subjects (95 healthy and 45 PACG of Indian/Chinese ethnicity, Age: 60.2±8.7 for PACG subjects and 57.7±10.1 for healthy subjects), the simulated deformation pattern of the iris during pupil constriction matched well with OCT images. We found that the iris stiffness was higher in PACG than in healthy controls (24.5±8.4 kPa vs 17.1±6.6 kPa with 40 kPa of active stress specified in the sphincter region; p < 0.001), whereas iris permeability was lower (0.41±0.2 mm2/kPa.s vs 0.55±0.2 mm2/kPa.s; p = 0.142).ConclusionThis study suggests that the biomechanical properties of the iris in PACG are different from those in healthy controls. An improved understanding of the biomechanical behavior of the iris may have implications for the understanding and management of angle-closure glaucoma.

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In vivo estimation of murine iris stiffness using finite element modeling

Cited by 10 publications

References 35 publications

Changes in Iris Stiffness and Permeability in Primary Angle Closure Glaucoma

Changes in Iris Stiffness and Permeability in Primary Angle Closure Glaucoma

Assessing Porcine Iris Elasticity and Mechanical Anisotropy with Optical Coherence Elastography

Changes in Iris Stiffness and Permeability in Primary Angle Closure Glaucoma

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