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Chaid Schwarz, Benjamin Thomas Aldrich, Kimberlee Burckart, Gregory Schmidt, Cynthia Reed, Mark A Greiner, Edward A Sander; Adhesion Strength of Descemet Membrane in Healthy and Diabetic Donor Corneas. Invest. Ophthalmol. Vis. Sci. 2016;57(12):2374.
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© 2017 Association for Research in Vision and Ophthalmology.
Descemet membrane endothelial keratoplasty (DMEK) is an increasingly popular surgical procedure for treating diseases involving the corneal endothelium. Anecdotal evidence suggests that differences in the force required to peel the Endothelium-Descemet membrane complex (EDM) during DMEK surgical preparation may contribute to the greater incidence of preparation failures observed in diabetic compared to non-diabetic donor tissues (Greiner et al., 2014). Here, we report on the development of a mechanical testing method for quantifying the peel strength of human donor corneas, and our progress on quantitatively assessing the putative differences between non-diabetic and diabetic tissues.
Corneoscleral tissues stored less than 14 days from procurement from control non-diabetic, non-severe diabetic, and severe diabetic donors 50-75 years old were used in this study. To reflect loading conditions used in surgical preparation, we applied cantilever bending to rectangular sections of corneal EDM during a continuous peel test. Using a thin Nitinol bar anchored to peripheral tissue with a calibrated force-displacement relationship, a displacement of 0.25 mm/s was applied to the EDM in order to separate EDM from the stromal layer over the length of the tissue section. Video tracking and Matlab were used to analyze bar displacement and calculate the force required to separate EDM from stroma over the course of the peel.
No significant difference was found in the average peel force/width (g/mm) necessary to separate EDM form stroma in non-diabetic (0.082 ± 0.011) and non-severe diabetic (0.079 ± 0.004) donor tissue (p = 0.907). In contrast, severe diabetic donor tissue required significantly greater force/width to peel EDM (0.103 ± 0.028) compared to both non-diabetic (p = 0.038) and non-severe diabetic (p = 0.029) tissue samples.
We have for the first time quantified the adhesion strength between Descemet membrane and the underlying stroma in human corneas. Differences in adhesion strength amongst non-diabetic, non-severe diabetic, and severe diabetic tissues suggest that severe diabetes mellitus may be a risk factor influencing donor preparation failures.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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