An Alternative Dmek Marking Technique: The Bubble That Stayed

To describe and evaluate an intraoperative orientation technique for Descemet membrane endothelial keratoplasty (DMEK) grafts using an intralamellar air bubble, as an alternative to conventional stromal marking methods such as peripheral triangular notching or stromal “F” or “S” stamping by creating an anterior lamellar hole. 

Traditional DMEK graft orientation relies on creating a peripheral triangular mark or stamping an “F” through the anterior stromal surface. While effective, these techniques require direct tissue manipulation and irreversible damage to the anterior lamella. We describe an alternative, non-contact orientation method adopted in a UK centre. Although this technique has been previously reported in Eye Bank literature, we describe a practical modification that streamlines DMEK tissue preparation.

We describe an alternative, non-contact orientation method in which a small air bubble is deliberately introduced between the partially folded Descemet membrane (DM) and endothelial layers during preparation. The bubble is positioned within the scroll prior to stamping, allowing the direct application of the standard F mark without creating an anterior button-hole. We present a step-by-step guide through intra-operative photographs of all stages of this technique, so that this technique may be easily adopted by other surgeons performing DMEK grafts. 

By utilizing pre-existing air bubbles naturally present in the preservative medium, rather than injecting air with a cannula after graft folding, we eliminate an additional procedural step. The same bubble is subsequently used to support graft marking, reducing preparation time and simplifying the workflow. The air bubble allows for application of the stamp, which facilitates immediate recognition of inverted grafts and reduces intraocular manipulation. The technique preserves endothelial integrity by avoiding mechanical trephine-edge notching or stromal stamping, minimizes potential endothelial cell loss related to marking, and eliminates permanent alterations to graft tissue. Additionally, the method reduces preparation time. 

Air bubble-assisted DMEK graft marking represents a simple, reproducible, and tissue-preserving alternative to conventional DMEK orientation techniques. This approach enhances intraoperative visualization, reduces mechanical trauma, and maintains graft integrity. Further prospective evaluation is warranted to quantify endothelial cell survival and clinical outcomes compared with traditional marking methods.