Abstract
Purpose :
To assess for when in performing penetrating keratoplasty does most corneal endothelial cell damage occur.
Methods :
A series of human donor corneas are stained with trypan blue prior to any manipulation, trephinated using a 7.5 mm trephine blade, stained with trypan blue and imaged on slit lamp. Any changes are noted. The corneal button is then bound using a 10-0 nylon suture over only one fourth the graft-host junction. After this first line of suture is placed, the cornea is restained with trypan blue and reimaged under slit lamp to assess for changes. This process of suture-then-stain is repeated for the second fourth, the third fourth, and the final fourth of the corneal graft-host junction until the entire corneal graf-host junction is sutured completely. The area in which trypan is taken up by corneal endothelium is estimated using the Magnetic Lasso Tool in Abode Photoshop 7.0 as has been previously described. Estimated area is tabulated and compared between buttons.
Results :
At baseline there is 0.005% trypan uptake prior to terphination in both corneas. After trephination first cornea shows 3.01% uptake, second shows 4.24% uptake. After the first quarter of sutures are placed 5.11% uptake is detected in the first cornea and 7.32% uptake is identified in the second. After the second quarter of suture is placed, 15.7% uptake is detected in the first cornea, 20.1% is detected in the second. After the third quarter of suture is placed, 16.7% uptake is detected in the first cornea, 22.1% is detected in the second. After the final quarter of suture is placed, 14.7% uptake is detected in the first cornea and the second cornea is damaged beyond any detection.
Conclusions :
Corneal endothelial viability is a prominent consideration before and after surgery. The use of vital dye, including trypan blue, is understood to reflect damage to endothelial cells and devitalization. We demonstrate that the second quarter of suture placed in the corneal button during penetrating keratoplasty shows the must uptake of trypan. This means that this step most likely is the source for most damage during suture, if damage occurs during suture. Further research is needed to replicate these findings to extend into statistical significance.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.