Abstract
Purpose:
Descemet’s membrane endothelial keratoplasty (DMEK) has improved visual recovery in patients with corneal endothelial disease. However, the procedure has received criticism for jeopardizing donor tissue during graft preparation. Standardization of graft preparation may support corneal surgeons and eye bank personnel in learning and safely performing the stripping procedure, thereby minimizing tissue loss. Here, we propose a novel tool designed specifically for preparation of Descemet’s membrane (DM) grafts.
Methods:
CNC milling was used to create a blunt trephine-like instrument that can be centered over the donor cornea. The device was used to deliberately damage endothelial cells in the corneal periphery by lowering it onto the cornea, thereby briefly touching the endothelium. A central 9 mm opening ensured that the 8 mm graft area plus a 0.5 mm safety margin were spared. Trypan blue 0.06% (VisionBlue®) was used to stain the denuded DM, and graft preparation was continued by peeling a narrow strip of peripheral DM using a razor blade as previously described (Kruse et al., Cornea 2011). Transmission electron microscopy (TEM) was used to confirm structural integrity of the denuded DM.
Results:
Use of the marker stamp resulted in the delineation of a peripheral band of denuded DM which readily stained with trypan blue. This aided in the visualization of DM during subsequent peeling steps. The central margin could be easily identified and the risk of the “rhexis” escaping centrally was reduced. Also, radial tears could be detected as they occurred and were therefore less likely to remain unnoticed. TEM confirmed that no structural deficits of DM were induced by removal of endothelial cells.
Conclusions:
Preparation of DM grafts can be further standardized by providing customized surgical instruments. The device presented here improves visualization of DM during creation of the peripheral margin for subsequent lifting of the margin and stripping of the graft. It thereby offers increased safety and reproducibility and may also shorten preparation times and learning periods. Damage to the membrane itself was not observed, suggesting that the ability to withstand grasping and pulling during DM stripping is not compromised.