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Meraf Amde Wolle, David DeMill, Maria A Woodward, Lauren Johnson, Shahzad Mian; The Endothelial Safety of Using Preloaded Descemet Membrane Endothelial Keratoplasty Graft. Invest. Ophthalmol. Vis. Sci. 2016;57(12):1244.
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© 2017 Association for Research in Vision and Ophthalmology.
Descemet Membrane Endothelial Keratoplasty (DMEK) surgeries are on the rise and ways to streamline the procedure, such as preloading tissue, would assist in increasing surgeon uptake. The goal of this study is to determine the safety of preloading DMEK grafts 24 hours prior to injection by analyzing endothelial cell loss (ECL) using commercially available software Metamorph and comparing it to the previously validated software Fiji.
Eighteen cadaveric corneas were prepared for DMEK using a standardized technique and loaded in a modified jones tube injector. Nine of the corneas were injected into Calcein AM vital dye after 1 minute, as controls. The remaining nine corneas were preloaded in the injector for 24 hours prior to injection. The stained corneas were imaged using an inverted fluorescent microscope (Fig 1). ECL was then analyzed and quantified by 2 different graders using Metamorph and Fiji (Fig 2). The study was powered to detect a 10% difference in cell loss between the two groups.
The control DMEK tissue resulted in 26.29%±9.58% ECL and the tissue stored for 24 hours prior to injection resulted in 22.60%±8.72% ECL (p=0.42). The mean (SD) pooled ECL as analyzed by Metamorph was 23.70% ±8.40% and by Fiji was 26.30%±7.55%. Interobserver agreement was 0.97 (0.87-0.99) for MetaMorph and 0.96 (0.84-0.99) for Fiji. The average time required for image analysis was 2 min for MetaMorph and 15 minutes for Fiji. Intraobserver agreement was 0.99 (0.94-1.00) for MetaMorph and 0.96 (0.82-0.99) for Fiji.
Preloading DMEK tissue in an injector does not result in significantly increased endothelial cell loss showing the clinical feasibility of such an approach. Clinical trials are needed to draw conclusions about clinical viability. Metamorph is a novel and accurate imaging software with increased efficiency and reproducibility in quantifying ECL as compared to the previously validated Fiji. Improving analysis techniques will have long lasting consequences on future experiments on endothelial graft preparation and surgical technique.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
Fig 1. A-Vital dye stained cornea image captured initially in 3D. B-Cross sections through the adjacent full cornea image showing the undulations of the tissue on the z axis. C-Overlay of the intensity of fluorescence at a given location.
Fig 2. MetaMorph (left) and Fiji (right) final images after analysis showing ECL (hyperfluorescent or black areas).
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