Abstract
Purpose:
To ascertain whether storage of pre-stripped donor tissue for 5 days is associated with wider (i.e. looser) DMEK scrolls, which may be easier to open intraoperatively.
Methods:
10 human corneas from 5 donors were pre-stripped and stored in Optisol GS. The tissue was then cut into a 7.5 mm graft with a Moria trephine, stained with trypan blue for 4 minutes, and measured from digital photos with Fiji by 2 observers who were masked from the tissue’s storage time. Five corneas were cut within 12 hours of pre-stripping and measured (Group A-12h), stored in Optisol GS as free-floating scrolls, and re-measured after 5 days (Group A-5d). The mates of Group A were stored as pre-stripped tissue, then cut and measured after 5 days (Group B-5d). Mean width was compared with a paired T-Test. Percentage change from the reference group (Group A-12h) were also compared between the grafts stored as free-floating scrolls and as pre-stripped tissue.
Results:
Median donor age was 54 years (Range 42-90). Scroll width decreased in Group A after storage for 5 days as a free-floating scroll (median: 1.14 vs. 1.06 mm; mean 1.21 vs. 1.10, P=0.01). Scroll width also decreased in the mates of Group A after storage for 5 days as pre-stripped tissue (median: 1.14 vs. 1.05 mm; mean 1.21 vs. 1.12 mm, P=0.02). There was no difference in the percentage decrease in scroll width between the group stored as a free-floating scroll and as pre-stripped tissue (7.2% vs. 8.8%, P=0.22).
Conclusions:
Contrary to our hypothesis, storing DMEK tissue decreases its scroll width, which may make it more difficult to open intraoperatively. Five days in Optisol GS has the same effect on scroll width, whether the graft is stored as a free-floating scroll or as pre-stripped tissue, which is not surprising. Price has postulated that DMEK grafts scroll because of endothelial cell swelling, Melles has hypothesized that it is because of the tissue’s elastic properties, and Moshirfar has confirmed the presence of elastin in the membrane. Longer storage times should make the endothelium more edematous and widen the scroll, but at least after 5 days, it does not. This raises interesting questions on the effects of Optisol GS on the collagens and elastin in the banded and non-banded zones of Descemet membrane in DMEK tissue.