Abstract
Purpose :
With organ culture, the graft is typically transferred from an isotonic dextran-free preservative culture medium (medium I) to a hypertonic storage medium (medium II, containing dextran T-500 6%) for deswelling before corneal transplantation. The purpose of this study was to determine the kinetics of the deswelling process of human corneal grafts in medium II.
Methods :
We examined prospectively the tomography of 24 corneas transferred into the dextran-containing medium II. Corneas were measured every hour after the transfer for 24 hours, using an anterior segment OCT (Tomey CASIA 2), without extracting the tissue from the container. The corneal thickness was measured with the manual measurement tool of the AS-OCT Software, version 3A.4. All analyzed corneas were improper for a corneal transplantation because of various conditions (contamination, detection of viral donor infection, injury of the graft button, etc.) and were not used for transplantation after the measures. We analyzed the corneal thickness hour by hour and determined for each cornea the percent of deswelling at 6, 12, and 18 hours compared to its maximal measured deswelling point at 24 hours.
Results :
The average central corneal thickness at baseline (t0) was 727±156µm. It reached 581±103, 506±84, 472±79 and 456±76 micrometers after 6, 12, 18 and 24 hours, respectively. The average deswelling of the cornea after 6 hours in dextran-containing medium reached a level of 55.5%±20.4% of the total measured deswelling, a level of 82.9%±13.9% at 12 hours and a level of 94.2%±6.4% at 18 hours, compared to 100% of the total measured deswelling at 24 hours (Figure 1).
Conclusions :
We demonstrated that the kinetics of the deswelling process in dextran-containing medium follow on average a non-linear hyperbolic curve. Considering a deswelling of 82.9% at 12 hours and 94.2% at 18 hours compared to complete deswelling after 24 hours, we assume that a time interval of less than 24 hours in medium II could be sufficient for subsequent grafting. Most probably 12 hours might be enough for clinical purposes. This result might help to keep storage in medium II as short as possible in order to escape from potential toxicity effects of dextran in culture medium II.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.