Pre-Descemets Endothelial Keratoplasty (PDEK)

The most popular endothelial keratoplasty (EK) technique is Descemets stripping endothelial keratoplasty (DSEK). Descemets membrane endothelial keratoplasty (DMEK) has advantages but is technically challenging. In 2013 Dua et al reported a pre-Descemets layer (Dua's layer, DL) in the posterior cornea and suggested how this could be exploited for EK. This was later developed and performed as Pre-Descemets endothelial keratoplasty (PDEK).

PDEK tissue is harvested by injecting air into the donor cornea and creating a type-1 big bubble (BB). The posterior bubble wall composed of endothelial cells, DM and DL is excised and inserted in the recipient eye. This tissue rolls less than DMEK tissue and is more robust allowing easy handling and unrolling in the eye. It can also be physically centred in the anterior chamber. The limitations are that on occasions a type-2 BB may form requiring a DMEK procedure. The PDEK graft size is smaller being limited by the size of the BB (around 8.5 mm). However, PDEK tissue can be taken form very young eyes with higher cell counts. Initial results, with regard to complications, visual acuity, refractive error and OCT changes are very encouraging making PDEK a viable option for EK.