Effect of Descemet Membrane Endothelial Keratoplasty Graft Storage Time on Graft Elasticity

The purpose of this study was to evaluate the effect of Descemet membrane endothelial keratoplasty (DMEK) graft storage time on its elastic properties, measured using atomic force microscopy (AFM).

Twenty human corneas (from 10 donors), unsuitable for transplantation, were obtained from the eye bank (S. Fyodorov Eye Microsurgery State Institution, Moscow). Ten DMEK grafts were prepared and stored in the corneal storage medium, Optisol-GS at 4°C after preparation, and AFM analysis was performed within 12 hours after preparation (group A). Ten paired corneas from the respective donors were stored in Optisol-GS at 4°C for 1 week after preparation before AFM analysis (group B). Data were analyzed using the Hertz model for the evaluation of the Young modulus of elasticity.

Force-distance curve analysis showed an increase in the Young modulus of elasticity in group B in comparison with that in group A, and the mean values were 10.4 ± 1.8 kPa and 6.77 ± 2.25 kPa, respectively (P < 0.001). There was no correlation between the Young modulus of elasticity and donor age (r = 0.110, P = 0.644), endothelial cell count (r = -0.145, P = 0.541), and procurement interval (r = 0.14, P = 0.755).

A longer graft storage time in cold storage medium was found to significantly reduce the elasticity of the DMEK graft. Clinically, this could potentially influence the unfolding of the DMEK graft within the anterior chamber during surgery and the postoperative detachment rate.