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Ashiyana Nariani, Dhivya Ashok Kumar, Amar Agarwal, Isaac Perry, Michael Tramber, Anthony N Kuo, Melissa B Daluvoy, Alan N Carlson, Terry Kim; Eye Bank Graft Preparation for Pre-Descemet's Endothelial Keratoplasty. Invest. Ophthalmol. Vis. Sci. 2016;57(12):1222.
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© ARVO (1962-2015); The Authors (2016-present)
Pre-Descemet's Endothelial Keratoplasty (PDEK) is gaining momentum as an effective alternative to current endothelial keratoplasty techniques. Eye banks should become proficient at preparing PDEK grafts effectively. This study evaluated factors influencing successful PDEK graft preparation and trialed novel strategies for quantifying PDEK graft thickness and endothelial cell loss (ECL) post-processing, as alternatives to specular microscopy.
An ex-vivo investigation of 15 corneas was trialed for PDEK graft preparation at the Miracles In Sight Eye Bank. Deep stromal air injection, using a 30-gaugle needle, was attempted to achieve a type 1 bubble, and if created, was then injected with balanced salt solution (BSS) to provide additional expansion. Details regarding the donor and factors leading to successful type 1 bubble formation were noted (Figure 1). Optical coherence tomography (OCT) was used to measure PDEK graft thickness. The graft endothelial surfaces were stained with trypan blue, digital photography obtained and ECL quantified using Fiji imaging software, both pre- and post- graft processing.
Of the 15 corneas trialed, 9 achieved a type 1 bubble, 2 achieved a type 2 bubble, and 4 had Descemet's membrane perforations. Of the 9 with an initial type 1 bubble, 2 subsequently perforated during BSS expansion, as did both type 2 bubbles. For the 7 (46.7%) successfully prepared PDEK grafts, all were created on first air injection attempt, mean bubble diameter was 8.11 millimeters (mm) and mean needle bevel position from limbus was 2.82 mm. Mean OCT graft thickness was 37.5 micrometers (µm), with standard deviation of 1.87 µm. Mean ECL pre- and post- graft processing were 8.26% and 24.8%, respectively.
With the innovation of PDEK, eye banks need to learn how to prepare PDEK grafts, minimizing corneal donor tissue wastage and ECL. A 46.7% success rate for PDEK graft preparation was achieved, and of those, a 24.8% mean ECL resulted post-processing. An increased number of air injection attempts decreased the likelihood of type 1 or 2 bubble formation. Donor age, horizontal needle bevel position, pre-processing endothelial cell density and ECL, did not affect graft preparation success, though needle depth was anecdotally noted to play a role. Additional investigation is needed to further optimize eye bank prepared PDEK grafts.
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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