Abstract
Purpose: :
To evaluate the effect of anterior chamber air bubbles on endothelial cells in Descemet’s Stripping Endothelial Keratoplasty (DSEK).
Methods: :
Twelve human donor corneas (six pairs) were sectioned using an automated microkeratome system (Moria ALTK System, Antony, France). One cornea of each pair was mounted on a Moria artificial anterior chamber and an air bubble was injected to fill 40% of the anterior chamber. The apparatus was then rotated 180 degrees for a total of 50 times to simulate air bubble trauma. The fellow cornea of each pair was used as a control. Endothelial grafts of all corneas were removed and stained with 0.25% trypan blue for 90 seconds followed by 0.2% alizarin red for 2 minutes. Digital photomicrographs of the stained grafts were then taken. Abnormally staining areas indicative of graft injury were digitally removed from the total graft area. The proportion of uninjured corneal endothelium was calculated by dividing the area of viable endothelial cells by the total graft area using the NIH Imaging/ImageJ.
Results: :
In this ex vivo model of air bubble trauma, the proportion of viable graft endothelium after air bubble injury was 79.8 ± 0.04 % (n=6). In comparison, the proportion of viable endothelium in the control group was 89.9 ± 0.02 % (n=6). The statistically significant mean difference of 10.1 % (P = 0.03) is indicative of greater endothelial injury following air bubble trauma. There was no significant difference in post-cut endothelial cell density and graft pachymetry between the two groups prior to experimentation.
Conclusions: :
In this model, the movement of anterior chamber air bubbles caused a moderate but significant amount of corneal endothelial cell damage compared to control. Intracameral air bubbles may therefore contribute to the loss of endothelial cell density following DSEK surgery. The size and, therefore duration, of anterior chamber air bubbles may need to be considered carefully given the potential harm and benefits of an air bubble tamponade. Further studies are needed to determine the in-vivo clinical significance.
Keywords: cornea: endothelium