Abstract
Corneal transplantation is the most commonly performed human tissue transplantation
procedure worldwide. Due to the large number of grafts, corneal graft failure has
become one of the most
common indications for corneal transplantation for immunological and non-immunological
reasons (e.g. recurrence of underlying disease, high intraocular pressure, grafted
guttae, transmitted
HSV or CMV infection). The relatively recently developed lamellar grafting techniques
have introduced certain potential complications that may lead to graft failure and
require approaches
other than penetrating keratoplasty for re-grafting. On the other hand, these
new lamellar techniques also offer new possibilities for salvaging failed penetrating
grafts, with potential
advantages over successive penetrating keratoplasties, such as lower intraoperative
risks, faster visual rehabilitation and reduced risk of immune reaction. Today, the
patient with good
healing who is satisfied with his graft before endothelial decompensation, with
low astigmatism and no stromal scars, represents the optimal condition for DMEK after
PKP. This can also be
combined with phacoemulsification (so-called triple DMEK). Otherwise, a penetrating
re-keratoplasty with a larger graft (typically excimer laser repeat PKP 8.5/8.6 mm)
is performed to treat
edema, scars and irregular astigmatism simultaneously. The medical history carries
weight in this decision! Re-DMEK in case of graft failure after DMEK and DSAEK does
not require any
modification of the standard technique and leads to good visual acuity results
if performed quickly. If there is clear stromal scarring after multiple (external)
DMEKs, PKP can also be
considered to rectify the situation. Otherwise causeless recurrent graft failures
must suggest herpetic or CMV endotheliitis and, after PCR analysis of the aqueous
humour aspirate, be
treated appropriately with medication.
Key words
penetrating keratoplasty (PKP) - Descemet membrane endothelial keratoplasty (DMEK)
- graft failure - technique - immune reaction - endotheliitis