Abstract
Purpose: :
To evaluate corneal endothelial cell damage in DSEK graft tissue due to anterior chamber air bubble trauma.
Methods: :
Six human research corneas acquired from the North Carolina Eye Bank were sectioned 300 micrometers deep using a Moria mechanical microkeratome and stored in Optisol GS at 4°C. Half of the paired corneas were placed on a Moria artificial chamber and a 30-40% air bubble was injected. The artificial chamber was then turned upside down and back 50 times to simulate normal bubble shifting that occurs in the first 48 hours following DSEK surgery. The corneas were then manually cut with an 8mm trephine and the endothelium was stained with trypan blue 0.25% and alizeran red S 0.2%. The control corneas were similarly cut and stained. All corneas were then photographed at 25x magnification, a montage was created with Photoshop, and the percentage of the total area of damaged endothelium was then calculated for each cornea.
Results: :
The mean donor age was 44 years (SD=24). The mean postmortem interval was 13.5 days (SD=10.5) and the mean postcut interval was 39 hours (SD=1.26). The mean corneal endothelial cell density prior to tissue cut for the air bubble eyes was 2656 cells/mm2 (SD=627) and 2493 cells/mm2 (SD=620) for the control eyes. The mean graft thickness for the bubbled eyes was 153 microns (SD=3) and 155 microns (SD=23) for the control. For bubbled eyes, the mean percentage of damaged endothelium was 56% (range 40 to 75%). In the control group, the mean percentage of damaged endothelium was 22% (range 10 to 40%). Between paired air bubble and control eyes, the mean difference in area of undamaged endothelium was 35% (SD=32%).
Conclusions: :
A shifting anterior chamber air bubble has the potential to cause corneal endothelial cell damage, as suggested by this model. Clinically, this factor might be considered when determining the size, and therefore duration, of anterior chamber bubbles. Further studies are needed to determine the in-vivo clinical significance.
Keywords: cornea: endothelium • cell survival • transplantation