Scrolling of the Donor Cornea in Dependence of Temperature and Osmolarity for Descemet Membrane Endothelial Keratoplasty

Abstract

Background After preparation of a graft for Descemet membrane endothelial keratoplasty (DMEK), the diameter of the graftʼs scroll varies significantly. In particular, narrow scrolls may complicate DMEK surgery. In this study we investigated how temperature, osmolarity, and deswelling of the donor tissue influence scrolling diameter. Material and Methods In this study we examined donor corneas that could not be used for transplantation. The diameter of the DMEK donor scrolls was measured after graft preparation by reflected light microscopy under different conditions: (1) The diameter of the roll was measured in Ringerʼs solution at temperatures of 5 °C, 24 °C and 35 °C. (2) To study the effect of different culture conditions we used 6% dextran-containing medium for 10 min, 20 min, 16 h and 24 h, and hyper- and hypoosmolar fluids (5% NaCl or aqua dest) for 5 min each. Results The median donors age was 62 years. The median endothelial cell density of the donor corneas was 1679 cells/mm2. The median diameter of the DMEK scroll was 1.35 mm in Ringerʼs solution at 24 °C (IQR, 1.04 – 1.89). In Ringerʼs solution at different temperatures, the scrolling diameter changed between 0.02 mm and 0.29 mm. The change in osmolarity resulted in a difference of 0.02 mm to 0.46 mm. Deswelling with dextran resulted in a change of scrolling diameter between 0.02 mm and 0.09 mm. Summary In this experimental case series, the diameter of the DMEK scroll did not change due to changes of temperature, osmolarity or deswelling. Influencing the graftʼs scroll to standardize and simplify the DMEK surgery remains an interesting goal for future studies.

Effect of Collagenase A on Descemet Membrane Endothelial Keratoplasty Scroll Tightness

“…The authors also assessed osmolality, scroll swelling, and deswelling on scroll tightness but did not report any relationship between those variables and scroll tightness. 17 From this study's findings, neither the hot (37°C) nor cold (4°C) temperature environment had a significant impact on scroll tightness when evaluated over 30 minutes of exposure. This is in line to what was published by Gruber et al, 17 who did not identify any significant impact on scroll tightness in relation to temperature.…”

“…17 From this study's findings, neither the hot (37°C) nor cold (4°C) temperature environment had a significant impact on scroll tightness when evaluated over 30 minutes of exposure. This is in line to what was published by Gruber et al, 17 who did not identify any significant impact on scroll tightness in relation to temperature. This provides some clarity on this topic and supports the belief that temperature does not influence scroll tightness.…”

“…16 Another more recent study evaluated the effects of temperature on scroll tightness. 17 The temperatures that were tested in this study were 5°C, 24°C, and 35°C, similar to that of the previous article. This study did not find any significant difference between the scroll tightness at each of those temperatures.…”

“…Previous research has evaluated the effects of temperature on scroll tightness but has published conflicting findings. 16,17 The first study evaluated the tightness of 10 scrolls over 3 temperature groups such as low (4°C), room temperature (20-25°C), and warm environment (35°C). 16 During their analysis, they reported a statistically significant decrease in scroll tightness as temperature increased.…”

“…15 The effects of temperature on scroll tightness were also explored as part of this article because temperature is an easy factor to control and can be implemented seamlessly into current DMEK protocols. In addition, previous studies performed on the effects of temperature on scroll tightness have been contradictory, 16,17 so this study attempted to clarify the impact of this variable on scroll tightness. The outcomes of this research will provide us insight into DMEK graft factors that determine scroll tightness.…”