P08-A131 Comparison of sterile donor tomography in the eye bank and previous keratometric measurements during the donor's lifetime.

PURPOSE: Sterile donor tomography in the eye bank can be used to minimise refractive surprises after corneal transplantation.The aim of this study was to compare sterile tomography of donor corneas in the eye bank with keratometric measurements of the same donors performed prior their death.

METHODS: Since 2018, 1246 donor sclerocorneal discs have been routinely measured using donor tomography, taken sterilely through their cell culture flask in medium II using the anterior segment optical coherence tomograph Casia 2 (Tomey Corp., Nagoya, Japan) and a custom-made Matlab software (The MathWorks Inc., Natick, Massachusetts, USA). Of all these donor corneas, 19 (1.5%) appeared to have been measured with Pentacam (Oculus Optikgeräte GmbH, Wetzlar, Germany) in the donors before death. Both measurements, taken at a mean interval of 35 ± 26 months, were compared using a Wilcoxon signed-rank test.

RESULTS: The mean steepest/flattest front surface radius and anterior astigmatism of the corneas measured with Pentacam amounted 7.66±0.35/7.93±0.37 mm, and 0.27±0.43 mm. Corresponding values of sterile donor tomography were respectively 7.48±0.31 [p<0.01]/7.77±0.25 [p=0.01] mm, and 0.29±0.35 [p=0.78] mm.At the posterior corneal surface, the Pentacam measured a mean steepest/flattest surface radius and astigmatism of 6.27±0.33/6.72±0.48 mm and 0.45±0.47 mm, whereas values of sterile donor tomography amounted 6.55±0.30 [p<0.01]/6.94±0.33 [p=0.04] mm and 0.39±0.26 [p=0.63] mm, respectively.The central corneal thickness amounted 575±52 µm with Pentacam, and 597±80 µm [p=0.20] with sterile donor tomography.

CONCLUSION: The front and back surface astigmatism as well as the central corneal thickness remained statistically unchanged after corneal excision and preservation in organ culture in comparison to measurement of the donor prior death. The statistically non-similar anterior and posterior radius of curvature between both methods must be seen in light of the known differing corneal topography between swept-source anterior segment optical coherence tomography and Scheimpflug imaging. These results suggest a merely minimal deformation caused by the storage and attachment of donor corneas to their holder in the cell culture flask for sterile donor tomography, causing a steeper anterior surface curvature but leaving the astigmatism still congruent with previous in situ conditions.