Intraocular Graft Unfolding Techniques in Descemet Membrane Endothelial Keratoplasty

Figure 1. Decision tree describing the use of the 4 basic Descemet graft unfolding techniques (techniques 1-4) and the 3 auxiliary techniques.

Figure 2. Diagram displaying the use of the basic Descemet graft unfolding techniques (techniques 1-4) in 100 consecutive Descemet membrane endothelial keratoplasty (DMEK) surgical procedures, either as a stand-alone technique or combined with 1 or 2 other techniques.

Figure 3. Intraoperative images of technique 1, the standardized no-touch Descemet membrane endothelial keratoplasty technique: unfolding a double Descemet roll. A, After injecting a double Descemet roll into the host anterior chamber, with both curls pointing upward (ie, a positive Moutsouris sign), gentle taps applied onto the outer recipient cornea with a cannula are used to start unfolding the graft. B, A small air bubble is positioned on top of the donor tissue to secure the Descemet graft in its upright orientation and to allow for centration of the graft by vibrating movements with the cannula onto the outer corneal surface. C, By enlarging the air bubble, the graft is fixated onto the iris while its peripheral edges are completely unfolded. D, The air is then aspirated from the interface between the Descemet graft and the cornea and injected underneath the Descemet graft to secure the transplant onto the host posterior stroma by leaving the anterior chamber completely filled with air for 1 hour. Throughout the unfolding process, direct physical contact between the graft and any instrument is carefully avoided.

Figure 4. Artist impression displaying the double Descemet roll and the Moutsouris sign. When the Descemet graft is oriented correctly within the anterior chamber (curls of the double roll facing upward), the tip of the cannula can be positioned inside a peripheral curl so that the tip appears blue because of the overlying blue-colored donor tissue (Moutsouris sign positive) (A and B). When the graft is positioned upside down (edges facing downward), the tip of the cannula does not find the curls so the tip will not change in color (Moutsouris sign negative) (C and D).

Figure 5. Intraoperative images of technique 2 (Dirisamer technique) : using 2 cannulas to unfold a single Descemet roll. A, After injection, if the donor tissue falls back into a single Descemet roll, the outer curl of the roll can often be separated from its larger body by gently tapping onto the outer corneal surface. B, Once the outer curl falls back onto the iris, it may be fixated by gentle pressure with 1 cannula onto the outer corneal surface. Meanwhile, gentle strokes are applied parallel to the remainder of the Descemet roll with a secondary cannula (C and D).

Figure 6. Intraoperative images of technique 3 (Dapena maneuver): unfolding the Descemet roll using a small air bubble. When techniques 1 and 2 fail or are considered less preferable (eg, in phakic eyes or eyes with a shallow anterior chamber), a small air bubble may be positioned on top of the graft, which is unfolded by manipulating the air bubble from the outer corneal surface with a cannula (A-D).

Figure 7. Intraoperative images of technique 4, the single sliding cannula maneuver to unfold a loose Descemet graft. A, After injecting a double Descemet roll in the host anterior chamber (with both curls pointing upward [ie, a positive Moutsouris sign]), the graft already shows a tendency to unroll by itself. After draining the side port to shallow the anterior chamber, the Descemet graft is unrolled by downward strokes with a cannula over the outer corneal surface, parallel to the body of the Descemet roll (B-D).

Figure 8. Intraoperative images of a combination of techniques 2 and 3 (ie, using 2 cannulas to unfold the single Descemet roll [Dirisamer technique]) and unfolding the Descemet roll by using a small air bubble (Dapena maneuver). With experience, any combination of the 4 basic Descemet graft unfolding techniques may be used to unfold the graft more quickly and with minimal manipulation. For example, the Descemet graft unfolding process may be started by using 2 cannulas to unroll the graft (Dirisamer technique) (A and B). Meanwhile, the process is completed using indirect manipulation with a small air bubble (Dapena maneuver) (C and D).