An Artificial Lens Capsule with a Lens Radial Stretching System Mimicking Dynamic Eye Focusing

Presbyopia is a common eye disorder among aged people which is attributed to the loss of accommodation of the crystalline lens due to the increasing stiffness. One of the potential techniques to correct presbyopia involves removing the lens substance inside the capsule and replacing it with an artificial lens. The development of such devices, e.g., accommodating intraocular lenses (AIOLs), relies on the understanding of the biomechanical behaviour of the lens capsule and the essential design verification ex vivo. To mimic the eye’s dynamic focusing ability (accommodation), an artificial lens capsule (ALC), from silicone rubber accompanied by a lens radial stretching system (LRSS) was developed. The ALC was manufactured to offer a dimension and deforming behaviour replicating the human lens capsule. The LRSS was calibrated to provide a radial stretch simulating the change of diameter of capsules during accommodating process. The biomechanical function of the ALC was addressed by studying its evolution behaviour and reaction force under multiaxial stretch from the LRSS. The study highlighted the convenience of this application by performing preliminary tests on prototypes of ophthalmic devices (e.g., AIOLs) to restore accommodation.

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Characterisation and Modelling of an Artificial Lens Capsule Mimicking Accommodation of Human Eyes

Polymers ◽

10.3390/polym13223916 ◽

2021 ◽

Vol 13 (22) ◽

pp. 3916

Author(s):

Huidong Wei ◽

James S. Wolffsohn ◽

Otavio Gomes de Oliveira ◽

Leon N. Davies

Keyword(s):

Silicone Rubber ◽

Shape Change ◽

Reaction Force ◽

Mechanical Tests ◽

Lens Capsule ◽

Intraocular Lenses ◽

Elastic Behaviour ◽

Human Lens ◽

Element Analysis ◽

Hyper Elastic

A synthetic material of silicone rubber was used to construct an artificial lens capsule (ALC) in order to replicate the biomechanical behaviour of human lens capsule. The silicone rubber was characterised by monotonic and cyclic mechanical tests to reveal its hyper-elastic behaviour under uniaxial tension and simple shear as well as the rate independence. A hyper-elastic constitutive model was calibrated by the testing data and incorporated into finite element analysis (FEA). An experimental setup to simulate eye focusing (accommodation) of ALC was performed to validate the FEA model by evaluating the shape change and reaction force. The characterisation and modelling approach provided an insight into the intrinsic behaviour of materials, addressing the inflating pressure and effective stretch of ALC under the focusing process. The proposed methodology offers a virtual testing environment mimicking human capsules for the variability of dimension and stiffness, which will facilitate the verification of new ophthalmic prototype such as accommodating intraocular lenses (AIOLs).

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Adhesion study of cultured human lens capsule cells on hydrophilic intraocular lenses coated with polyethylene glycol

Journal of Cataract & Refractive Surgery ◽

10.1016/j.jcrs.2014.11.047 ◽

2015 ◽

Vol 41 (7) ◽

pp. 1478-1483 ◽

Cited By ~ 3

Author(s):

Magda Massae Hata Viveiros ◽

Ricardo Torres Soares ◽

Michelle Sako Omodei ◽

Cláudia Aparecida Rainho ◽

Carlos Roberto Padovani ◽

...

Keyword(s):

Polyethylene Glycol ◽

Lens Capsule ◽

Intraocular Lenses ◽

Human Lens

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P 229 Growth of human lens epithelial cells on the anterior lens capsule in vitro

Vision Research ◽

10.1016/0042-6989(95)90545-6 ◽

1995 ◽

Vol 35 ◽

pp. S199

Author(s):

J.H. Meyer ◽

J. Schmidt ◽

F. Eppinger ◽

B. Flügel ◽

K.U. Löffler ◽

...

Keyword(s):

Epithelial Cells ◽

Lens Capsule ◽

Human Lens ◽

Lens Epithelial Cells ◽

Human Lens Epithelial Cells ◽

Anterior Lens Capsule

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Simulation of Light Efficiency for Aged People and Data-Analysis of an Optimal Illuminance with Aging Models of the Human Lens

JOURNAL OF THE ILLUMINATING ENGINEERING INSTITUTE OF JAPAN ◽

10.2150/jieij1980.82.8_564 ◽

1998 ◽

Vol 82 (8) ◽

pp. 564-572 ◽

Cited By ~ 2

Author(s):

Katsunori Okajima ◽

Michiko Iwata

Keyword(s):

Data Analysis ◽

Human Lens ◽

Aged People ◽

Aging Models ◽

Light Efficiency

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An immunoelectron microscope study of the aged human lens capsule

Experimental Eye Research ◽

10.1016/0014-4835(92)90051-s ◽

1992 ◽

Vol 54 (3) ◽

pp. 393-401 ◽

Cited By ~ 28

Author(s):

George E. Marshall ◽

Anastasios G.P. Konstas ◽

Nikolaos E. Bechrakis ◽

William R. Lee

Keyword(s):

Microscope Study ◽

Lens Capsule ◽

Human Lens

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Human Anterior Lens Capsule as a Biologic Substrate for the Ex Vivo Expansion of Limbal Stem Cells in Ocular Surface Reconstruction

Cornea ◽

10.1097/ico.0b013e318033bd0f ◽

2007 ◽

Vol 26 (4) ◽

pp. 473-478 ◽

Cited By ~ 40

Author(s):

Ahmed Galal ◽

Juan J Perez-Santonja ◽

Jose Luis Rodriguez-Prats ◽

Marta Abad ◽

Jorge Alio

Keyword(s):

Stem Cells ◽

Surface Reconstruction ◽

Ocular Surface ◽

Ex Vivo ◽

Ex Vivo Expansion ◽

Lens Capsule ◽

Limbal Stem Cells ◽

Ocular Surface Reconstruction ◽

Anterior Lens Capsule

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On the Anticataractogenic Effects of L-Carnosine: Is It Best Described as an Antioxidant, Metal-Chelating Agent or Glycation Inhibitor?

Oxidative Medicine and Cellular Longevity ◽

10.1155/2016/3240261 ◽

2016 ◽

Vol 2016 ◽

pp. 1-11 ◽

Cited By ~ 4

Author(s):

Hamdy Abdelkader ◽

Michael Longman ◽

Raid G. Alany ◽

Barbara Pierscionek

Keyword(s):

Epithelial Cells ◽

Antioxidant Activities ◽

Ex Vivo ◽

Antioxidant Properties ◽

Radical Scavenging ◽

Human Lens ◽

Lens Epithelial Cells ◽

Metal Chelating ◽

Human Lens Epithelial Cells

Purpose.L-Carnosine is a naturally occurring dipeptide which recently gained popularity as an anticataractogenic agent due to its purported antioxidant activities. There is a paucity of research and conclusive evidence to support such claims. This work offers compelling data that help clarify the mechanism(s) behind the anticataract properties of L-carnosine.Methods.Direct in vitro antioxidant free radical scavenging properties were assayed using three different antioxidant (TEAC, CUPRAC, and DPPH) assays. Indirect in vitro and ex vivo antioxidant assays were studied by measuring glutathione bleaching capacity and total sulfhydryl (SH) capacity of bovine lens homogenates as well as hydrogen-peroxide-stress assay using human lens epithelial cells. Whole porcine lenses were incubated in high galactose media to study the anticataract effects of L-carnosine. MTT cytotoxicity assays were conducted on human lens epithelial cells.Results.The results showed that L-carnosine is a highly potent antiglycating agent but with weak metal chelating and antioxidant properties. There were no significant decreases in lens epithelial cell viability compared to negative controls. Whole porcine lenses incubated in high galactose media and treated with 20 mM L-carnosine showed a dramatic inhibition of advanced glycation end product formation as evidenced by NBT and boronate affinity chromatography assays.Conclusion.L-Carnosine offers prospects for investigating new methods of treatment for diabetic cataract and any diseases that are caused by glycation.

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