Dataset Information

A standardized methodology for longitudinal assessment of corneal endothelial morphometry in eye banked corneas.

ABSTRACT: Eye banked research-grade human donor corneas serve as principal ex vivo source for studying the mechanisms that underlie corneal endothelial cell damage/death and survival. Wide-field specular microscopy can be used for corneal endothelial visualization and allows for indirect assessment of endothelial cell function by analyzing endothelial cell density and morphometric parameters. However, a standardized approach is needed to observe corneal endothelial changes over time. This protocol describes reliable ex vivo methods for consecutive analyses of human donor corneal endothelial cell density and morphometric parameters change using a wide-field dual imaging specular microscope. This protocol involves tissue warming, acquisition and analysis of specular endothelial images, assessment of corneal layers with the new Enhance mode, optical pachymetry measurement, and qualitative image quality grading scales. This quantitative and qualitative evaluation of donor corneas allows for a systematic analysis of endothelial dynamic responses to ex vivo induced stress and can be used as a valuable tool to better elucidate specular findings and mechanisms mediating corneal endothelial cell loss in corneal disease and after transplantation.

SUBMITTER: Luznik Z

PROVIDER: S-EPMC6888603 | biostudies-literature | 2019

REPOSITORIES: biostudies-literature

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A standardized methodology for longitudinal assessment of corneal endothelial morphometry in eye banked corneas.

Lužnik Zala Z Sun Zhongmou Z Yin Jia J Benetz Beth Ann BA Lass Jonathan H JH Dana Reza R

Journal of biological methods 20191120 4

Eye banked research-grade human donor corneas serve as principal <i>ex vivo</i> source for studying the mechanisms that underlie corneal endothelial cell damage/death and survival. Wide-field specular microscopy can be used for corneal endothelial visualization and allows for indirect assessment of endothelial cell function by analyzing endothelial cell density and morphometric parameters. However, a standardized approach is needed to observe corneal endothelial changes over time. This protocol ...[more]

PMID: 31890720

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Project description:BackgroundIndividuals who have failed one or more full thickness penetrating keratoplasties may be offered repeat corneal surgery using an artificial or donor cornea. An artificial or prosthetic cornea is known as a keratoprosthesis. Both donor and artificial corneal transplantations involve removal of the diseased and opaque recipient cornea (or the previously failed cornea) and replacement with another donor or prosthetic cornea.ObjectivesTo assess the effectiveness of artificial versus donor corneas in individuals who have had one or more failed donor corneal transplantations.Search methodsWe searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2019, Issue 11); Ovid MEDLINE; Ovid Embase; LILACS (Latin American and Caribbean Health Sciences Literature database); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). We did not use any date or language restrictions in the electronic search for trials. We last searched the electronic databases on 4 November 2019.Selection criteriaTwo review authors independently assessed reports from the electronic searches to identify randomized controlled trials or controlled clinical trials. Any discrepancies were resolved by discussion or consultation.Data collection and analysisWe used standard methodological procedures expected by Cochrane. For discussion purposes, we summarized findings from relevant comparative case series. We performed no data synthesis.Main resultsWe did not identify any randomized controlled trials or controlled clinical trials comparing artificial corneas with donor corneas for repeat corneal transplantations.Authors' conclusionsThe optimal management for those individuals who have failed a conventional corneal transplantation is unknown. Currently, in some centers, artificial corneal devices are routinely recommended after just one graft failure, while in other centers, they are not recommended until after multiple graft failures, or not at all. To date, there have been no controlled trials comparing the visual outcomes and complications of artificial corneal devices (particularly the Boston type 1 keratoprosthesis, which is the most commonly implanted artificial corneal device) with repeat donor corneal transplantation, in order to guide surgeons and their patients. Such a trial is needed and would offer significant benefit to an ever-increasing pool of people with visual disability due to corneal opacification, most of whom are still in productive stages of their lives.

Project description:ObjectiveTo validate a new method for reconstructing corneal biomechanical properties from air puff corneal deformation images using hydrogel polymer model corneas and porcine corneas.MethodsAir puff deformation imaging was performed on model eyes with artificial corneas made out of three different hydrogel materials with three different thicknesses and on porcine eyes, at constant intraocular pressure of 15 mmHg. The cornea air puff deformation was modeled using finite elements, and hyperelastic material parameters were determined through inverse modeling, minimizing the difference between the simulated and the measured central deformation amplitude and central-peripheral deformation ratio parameters. Uniaxial tensile tests were performed on the model cornea materials as well as on corneal strips, and the results were compared to stress-strain simulations assuming the reconstructed material parameters.ResultsThe measured and simulated spatial and temporal profiles of the air puff deformation tests were in good agreement (< 7% average discrepancy). The simulated stress-strain curves of the studied hydrogel corneal materials fitted well the experimental stress-strain curves from uniaxial extensiometry, particularly in the 0-0.4 range. Equivalent Young´s moduli of the reconstructed material properties from air-puff were 0.31, 0.58 and 0.48 MPa for the three polymer materials respectively which differed < 1% from those obtained from extensiometry. The simulations of the same material but different thickness resulted in similar reconstructed material properties. The air-puff reconstructed average equivalent Young´s modulus of the porcine corneas was 1.3 MPa, within 18% of that obtained from extensiometry.ConclusionsAir puff corneal deformation imaging with inverse finite element modeling can retrieve material properties of model hydrogel polymer corneas and real corneas, which are in good correspondence with those obtained from uniaxial extensiometry, suggesting that this is a promising technique to retrieve quantitative corneal biomechanical properties.

Dataset Information

A standardized methodology for longitudinal assessment of corneal endothelial morphometry in eye banked corneas.

Publications

A standardized methodology for longitudinal assessment of corneal endothelial morphometry in eye banked corneas.

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