DMEK lenticule preparation from donor corneas using a novel 'SubHyS' technique followed by anterior corneal dissection.

Purpose: To describe a novel submerged hydro-separation (SubHyS) technique followed by anterior corneal dissection to prepare a Descemet endothelial graft (DEG) for Descemet's membrane endothelial keratoplasty from human donor corneas.

Methods: 30 human donor corneas were immersed in liquid (organ culture (OC) storage medium). Using a 25-gauge needle, approximately 0.3 mL of OC was injected (SubHyS) in the posterior stroma to create a liquid bubble. The bubbled cornea was mounted onto a modified artificial chamber with the epithelial side facing the air. The endothelium was protected with a viscoelastic solution. The anterior cornea was excised with a Barron radial vacuum trephine and the residual peripheral stroma was removed manually using micro-scissors. The DEG was dismounted and washed. The endothelial cell density (ECD) and mortality of the prepared DEG was determined. All the DEGs were preserved in deturgescent medium for 7 days using a cornea claw which was fixed to the sclera. ECD and mortality were checked post preservation.

Results: Complete detachment of Descemet's membrane and stroma was achieved in all 30 cases. Bubble burst was observed in five cases (excluded from the study) due to overfilling of the liquid. The average diameter of the excised DEG was 10.96 mm. The average endothelial cell loss post preservation was 27.69%. Histological analysis confirmed elimination of the residual stroma (n=13).

Conclusions: The DEGs can be preserved in a deturgescent medium for up to 7 days. The procedure provides a standardised, pre-validated (quality assured), pre-separated, no-touch, ready-to-use tissue and also reduces the preparation time. Further, the tissues can be trephined as per the surgeon's convenience and can either be rolled or a contact lens could be used for final delivery of the DEG using a surgical glide.