The role of novel DMEK graft shapes in facilitating intraoperative unscrolling

To evaluate whether the preparation of Descemet membrane endothelial keratoplasty (DMEK) grafts into various shapes affect their propensity to scroll as compared with the conventional circular graft design.

Prospective randomized laboratory-based study, using nine pre-stripped DMEK corneal grafts unfit for transplantation. Each graft was trephinated into a standard circular 8-mm shape, stained with trypan blue, and then immersed in balanced salt solution (BSS). The width of the DMEK graft scroll was measured, and photographs were obtained. The graft was then cut into one of three pre-selected shapes (four peripheral punches, four radial cuts, Maltese cross). These newly shaped grafts were then replaced in BSS and again photographed. The scroll widths, as well as pre- and post-preparation scroll width-to-height ratios, were calculated and compared.

Nine pre-stripped DMEK corneal grafts (mean donor age ± SD 73.1 ± 9.3 years, range 58-85 years) were included. The mean pre-cut scroll widths for the three selected shapes were statistically similar. Following graft preparation into their assigned shapes, the mean post-preparation scroll widths (and corresponding change from pre-preparation measurements) were 1.73 ± 0.16 mm (- 3.6%) for the 4-peripheral punches, 2.59 ± 0.35 mm (+ 0.2%) for the 4-radial cuts and 4.13 ± 0.63 mm (+ 20.1%) for the Maltese cross (P = 0.0013). Therefore, the Maltese cross design resulted in a wider scroll than its pre-preparation control.

Certain DMEK graft shapes may be less prone to scrolling than others. The Maltese cross graft design scrolled less tightly than the other experimental graft shapes. Future studies may elucidate intraoperative scrolling behavior of these DMEK graft shapes within the anterior chamber.