The distribution of strain in the human cornea

T, Shin; Vito, Raymond P.; Johnson, Lindsay W.; McCarey, Bernard E.

doi:10.1016/s0021-9290(97)84433-8

Cited by 96 publications

(79 citation statements)

References 19 publications

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“…4 When subject to compression or stretching, the cornea reorganizes its layers, increasing in elasticity in order to reach a new equilibrium. 5,6 Corneal stability relies on different factors, such as intraocular pressure (IOP) or the action of extraocular muscles, 7 but it can also be affected by other elements, such as refractive surgery. [8][9][10] Most refractive surgery procedures modify the biomechanics of the cornea, because of the fact that ablation itself can have an impact upon the cornea's hysteresis response.…”

Section: Introductionmentioning

confidence: 99%

Corneal densitometry after photorefractive keratectomy, laser-assisted in situ keratomileusis, and small-incision lenticule extraction

Poyales

Garzón

Mendicute

et al. 2017

Eye

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Section: Introductionmentioning

confidence: 99%

Corneal densitometry after photorefractive keratectomy, laser-assisted in situ keratomileusis, and small-incision lenticule extraction

Poyales

Garzón

Mendicute

et al. 2017

Eye

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“…Tensile testing was performed under stress control at engineering stresses up to 500 kP a corresponding to engineering strains (∆L/L) as large as 5%. This value is beyond strains associated with normal changes in intraocular pressure which are ∼1% [77], but relevant to injury and some surgical procedures. Because the cornea tissue was substantially more compliant than the load train, actuator displacement was sufficient to monitor axial strain.…”

Section: Methodsmentioning

confidence: 94%

“…Previous studies on cornea mechanics have typically employed a tensile strip method [64,3,35,45,89,86], or a more physiologically relevant inflation method [88,44,34,77]. These measurements have been used, for example, to study the efficacy of cross-linking agents as means to counteract keratoconous [86,80].…”

Section: Introductionmentioning

confidence: 99%

“…The collagen fibrils are uniform in diameter, run parallel and equidistant within each lamella, and subtend large angles between adjacent lamellae [49,13]. Numerous experiments have shown that the mechanical behavior of the cornea is anisotropic, viscoelastic, and highly nonlinear [64,88,2,44,36,34,77,46,87,14]. It is assumed that the mechanical anisotropy arises from the preferred orientations of the collagen fibrils in the plane of the stroma which has been characterized for humans and certain species of primates by X-ray diffraction [58,21,1,11].…”

Section: Introductionmentioning

confidence: 99%

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The mechanics of soft biological composites.

Nguyen

Grazier²,

Boyce³

et al. 2007

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Biological tissues are uniquely structured materials with technologically appealing properties. Soft tissues such as skin, are constructed from a composite of strong fibrils and fluid-like matrix components. This was the first coordinated experimental/modeling project at Sandia or in the open literature to consider the mechanics of micromechanically-based anisotropy and viscoelasticity of soft biological tissues. We have exploited and applied Sandia's expertise in experimentation and mechanics modeling to better elucidate the behavior of collagen fibril-reinforced soft tissues.The purpose of this project was to provide a detailed understanding of the deformation of ocular tissues, specifically the highly structured skin-like tissue in the cornea. This discovery improved our knowledge of soft/complex materials testing and modeling. It also provided insight into the way that cornea tissue is bio-engineered such that under physiologically-relevant conditions it has a unique set of properties which enhance functionality. These results also provide insight into how non-phsyiologic loading conditions, such as corrective surgeries, may push the cornea outside of its natural design window, resulting in unexpected non-linear responses. Furthermore, this project created a clearer understanding of the mechanics of soft tissues that could lead to bio-inspired materials, such as highly supple and impact resistant body armor, and improve our design of human-machine interfaces, such as micro-electricalmechanical (MEMS) based prosthetics. Through this study,

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“…Such work includes an analysis of cornea strain distribution by Shin, et al [8] and a micro-structural analysis of the cornea by Johnson [9].…”

Section: Introductionmentioning

confidence: 99%

Finite Element Model of Cornea Deformation

Crouch

Merriam²,

Crouch

2005

Lecture Notes in Computer Science

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Abstract. Cornea surgeons have observed that changes in cornea curvature can follow cataract surgery and cause astigmatism. The placement of surgical incisions has been shown to influence these curvature changes. Though empirical data has been collected about this phenomenon, a biomechanical model has not been employed in predicting post-surgical outcomes. This work implemented an incised finite element model of the eye to investigate factors influencing corneal shape after surgery. In particular, the effects of eye muscle forces and intra-ocular pressure were simulated. Cornea shape change was computed via finite element analysis, and the resulting change in cornea curvature was measured by fitting quadratic curves to the horizontal and vertical meridians of the cornea. Results suggest that these two sources of deforming force counteract each other and contribute to astigmatism in perpendicular directions.

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The distribution of strain in the human cornea

Cited by 96 publications

References 19 publications

Corneal densitometry after photorefractive keratectomy, laser-assisted in situ keratomileusis, and small-incision lenticule extraction

Corneal densitometry after photorefractive keratectomy, laser-assisted in situ keratomileusis, and small-incision lenticule extraction

The mechanics of soft biological composites.

Finite Element Model of Cornea Deformation

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