Quantitative Analysis Of Apoptosis Signs In Corneal Grafts Before Preparation In Endothelial Keratoplasty And Correlation To Donor Tissue Characteristics And Postoperative Parameters

Published 2024 - 42nd Congress of the ESCRS

Reference: FP22.08 | Type: Free paper | DOI: 10.82333/qjcg-ev35

Authors: Nicolas Scherer* ¹ , Stefan Kassumeh ¹ , Nikolaus Luft ¹ , Martin Dirisamer ¹ , Siegfried Priglinger ¹ , Wolfgang Mayer ¹

¹Department of Ophthalmology,LMU University Hospital,Munich,Germany

Purpose

This study provides a quantitative analysis of endothelial apoptosis signs in corneal grafts before preparation for Descemet Membrane Endothelial Keratoplasty (DMEK) in patients with Fuchs' Endothelial Dystrophy (FED). The amount of apoptosis is correlated with donor tissue associated aspects such as preservation time as well as postoperative parameters such as endothelial cell density (ECD). Furthermore, cases with and without apoptosis signs are compared regarding postoperative ECD and corneal pachymetry (CP).

Setting

Prospective experimental study at the Department of Ophthalmology, LMU University Hospital, LMU Munich, Germany.

Methods

Preparation of the corneal graft in 36 DMEK or combined DMEK and cataract surgery (triple DMEK) cases was recorded intraoperatively using the Zeis Callisto Eye device (Carl Zeiss AG). Graft staining and preparation was conducted by the surgeon immediately before transplantation using trypan blue and a no touch liquid bubble dissection technique. Apoptosis areas unmasked by staining before starting preparation were classified using a target grid with a central 8,25- and 4-mm zone. The amount of apoptosis was quantified based on pixel using the software GIMP version 2.10.36. Statistical analysis including Spearman rank-order correlation test and Mann-Whitney U test was conducted using SPSS version 29 (IBM).

Results

Trypan blue staining unmasked apoptosis signs in 20 of 36 corneal grafts (55.6%) before preparation. The mean percentage of apoptosis related to the complete endothelium was 2.53% (SD 1.67%) (range 0.20% to 6.81%). 9 cases (45%) showed apoptosis inside the 8.25 mm zone (mean value 0.37% SD 1.02%) and none inside the 4 mm zone. There was no significant correlation between the extend of apoptosis and donor tissue preservation time (Spearman Rho, r=-0.071, p=0.766) or the postoperative ECD (Spearman Rho, r=0.211, p=0.451). Mann Whitney test showed no significant difference in postoperative ECD (z=-1.502, p=0.293) or CP (z=-0.767, p=0.443) between cases with and without apoptosis. Further data is acquired and will be presented at the congress.

Conclusions

This study is one of very few analysing the presence and extend of endothelial apoptosis in corneal grafts before preparation. While over 50% of the grafts showed endothelial apoptosis before beginning preparation, the mean percentage of apoptosis was rather small and showed a big range. Although the 8.25 mm zone was affected in half of all cases, the presence and amount of apoptosis at least in this study did not seem to exert a negative influence on postoperative factors like ECD and CP. Further research is necessary to evaluate the effect of those apoptosis areas on postoperative outcome and to examine whether the amount of apoptosis or rather the affection of the graft centre is the decisive aspect.