Descemet-stripping automated endothelial keratoplasty: insertion using a novel 40/60 underfold technique for preservation of donor endothelium.

PURPOSE: To describe a technique for insertion of an asymmetrically folded donor graft to minimize endothelial damage during Descemet-stripping automated endothelial keratoplasty.
METHODS: The tissue is folded in a 40/60 underfold rather than the commonly used 60/40 overfold. It is then grasped with the insertion forceps by using a prone hand position. The hand is rotated clockwise until it is supine, bringing the 60% side of the fold anteriorly, and then the tissue is inserted into the anterior chamber.
RESULTS: In 112 eyes, conventional 60/40 overfold insertion technique resulted in a 36% loss in endothelial cell density at 6 months. In 36 eyes, the new 40/60 underfold technique results in a 26% cell loss. This difference of 10% was statistically significant (P = 0.001).
CONCLUSIONS: This simple modification to a commonly used folding technique reduces trauma to the exposed peripheral endothelium in a 60/40 overfolded "taco," which is due to contact with the donor trephine block or other surface. It is a slight modification to a commonly used technique for graft insertion and can be easily implemented to reduce postoperative endothelial cell loss.