Abstract
Background The aim of this study was to compare the incidence of immune reactions and endothelial
cell loss after penetrating keratoplasty (PKP) vs. Descemet membrane endothelial keratoplasty
(DMEK) in patients with Fuchs endothelial dystrophy (FED).
Patients and Methods In the present retrospective study, a total of 962 surgeries (225 excimer laser PKP
and 727 DMEK) of 700 patients performed between 28.06.2007 and 27.08.2020 in the Department
of Ophthalmology at Saarland University Medical Center UKS were statistically evaluated.
On the one hand, the prevalence and the temporal course of the immune reactions that
occurred were analysed using the Kaplan-Meier method, as well as the effect of the
immune reactions on the endothelial cells and corneal thickness. Secondly, endothelial
cell density, pleomorphism, and polymegethism of the endothelial cells were evaluated
for the time points U1 = preoperative, U2 = 6 weeks postoperative, U3 = 6 to 9 months
postoperative, U4 = 1 to 2 years postoperative, and U5 = 5 years postoperative. In
addition, statistical tests were carried out for differences between the two types
of surgery and in the longitudinal course.
Results A total of 54 immune reactions occurred during the observed period, whereby the probability
of such a reaction was significantly greater in the PKP group with 8.9% than in the
DMEK group with 4.5% (p = 0.011). The comparison of the two Kaplan-Meier curves also
showed a significant difference between the two surgical techniques in the log-rank
test (p = 0.012). The endothelial cell loss due to the immune reaction was only significant
in PKP (p = 0.003). For all surgical procedures, endothelial cell density decreased
significantly with time in both surgical techniques (p < 0.0001 in each case), but
more strongly with DMEK than with PKP (p < 0.0001). Furthermore, this cell density
was significantly higher with PKP than with DMEK for the whole observation time (p < 0.0001).
Polymegethism decreased significantly in the DMEK group (p < 0.0001). Pleomorphism
was significantly higher, on average, in DMEK than in PKP (p < 0.0001).
Conclusion The prognosis of DMEK in patients with FED seems to be more favourable after immune
reactions than that of PKP, as not only were immune reactions less frequent, but they
were also milder. However, endothelial cell density was significantly higher in the
PKP group during the entire follow-up.
Key words Fuchs endothelial dystrophy - penetrating keratoplasty - Descemet membrane endothelial
keratoplasty - endothelial cell density - immune reaction
