Abstract
Purpose: :
To present an in vivo examination of endothelial function after Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK) and to relate this measured endothelial function with donor graft characteristics.
Methods: :
Ten eyes from nine patients undergoing routine elective DSAEK by the authors were enrolled. Each eye was imaged with an anterior segment optical coherence tomography unit (Visante: Carl Zeiss Meditec; Jena, Germany) at five time points: immediately pre-operatively and at one hour, one day, one week, and one month post-operatively. Each recorded image was subsequently analyzed using the unit’s software to provide stratified central pachymetric data for the host cornea, donor graft, and overall thickness of the corneal complex at each time point. These pachymetric data were then plotted against time for each individual patient to yield deturgescence rate information for the host cornea and donor graft. Using these deturgescence rates, the collective graft endothelial function was examined against graft characteristics (endothelial cell count, storage time, age of donor).
Results: :
The pachymetric change over time corresponded to an exponential decay. Based on this model, the mean calculated "half-life" of the stroma was 3.90 days (SD=2.28 days) and of the graft was 3.91 days (SD=2.15 days). Using this parameter, over 95% of the deturgescence from peak post-operative values would be expected to occur by 18 days.Regression analysis of the deturgescence rates (decay rates) against storage time showed no direct relationship: R2<0.001, p=0.95 for stroma; R2<0.01, p=0.83 for graft. Regression analysis of the deturgescence rates against pre-operative endothelial cell count showed no direct relationship: R2<0.33, p=0.10 for stroma; R2<0.001, p=0.96 for graft. Regression analysis of the deturgescence rate against donor age also showed no direct relationship: R2<0.12, p=0.35 for stroma; R2<0.009, p=0.79 for graft.
Conclusions: :
Using post-operative graft deturgescence as a proxy for collective corneal endothelial function, the function of endothelial cells in the first post-operative month after DSAEK does not appear to be directly affected by the duration of graft storage, donor age, or pre-operative endothelial cell count of the graft. Pachymetric "steady-state" from peak values of the average post-DSAEK cornea would be expected to occur within 18 days.
Keywords: cornea: clinical science • imaging/image analysis: clinical • cornea: endothelium