Abstract
Purpose :
To evaluate the scrolling pattern of DMEK grafts following paired small radial incisions (hinges) based on incision length and donor age.
Methods :
Eye bank prepared DMEK grafts were trephined to 7.75mm. The grafts were submerged in BSS and given 60 seconds to form a stable scroll. Scrolling pattern was documented as a single scroll, double scroll, or trifold. High resolution images were obtained to calculate scroll width. The graft was then flattened, and a pair of small radial incisions (hinges) were cut into the edge of the graft, with 120o of separation between incisions. Initially, a uniform hinge length of 0.5mm was used. The modified graft was then placed back into BSS fluid and encouraged to form a trifold with incisions at the base of the triangle. Scrolling pattern was again documented after 60 seconds of stability. The graft was then flattened and the hinges extended to 1.0mm in length, and then again to 1.5mm in length. After each extension, the graft was allowed to re-scroll and the scrolling pattern was again documented. Graft width was then measured from images obtained for each graft using a stage micrometer calibration with ImageJ. For scrolls, graft width was measured at the widest point of the scroll. For trifolds, graft width was measured as the shortest edge length of the trifold. Scrolling pattern and graft width were then compared across donor age and hinge length to evaluate the impact of adding hinges to DMEK grafts.
Results :
In total 15 grafts were obtained. One was excluded after an extraneous tear occurred during testing. Of the remaining grafts, 71% (10/14) achieved a stable trifold after adding hinges, compared to 0% (0/14) prior. For grafts age ≤65, 100% (10/10) achieved a stable trifold after adding hinges, compared to 0% (0/4) of grafts age >65. For grafts age ≤65, 60% (6/10) achieved a stable trifold with a hinge length ≤0.5mm; 80% (8/10) achieved a trifold with a hinge length ≤1.0mm; and 100% (10/10) achieved a trifold with a hinge length ≤1.5mm. Mean graft width (1499µm ± 445µm) increased with donor age prior to addition of hinges. After addition of hinges, mean graft width (5618 µm ± 900µm) was 2.8x higher, but remained stable with donor age.
Conclusions :
Paired small radial incisions (hinges) can be used to induce a trifold pattern in DMEK grafts age ≤65. Longer hinge lengths result in more a consistent trifold conformation.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.