Endothelial Morphometry by Image Analysis of Corneas Organ Cultured at 31 degrees C
Abstract
Purpose. To determine the factors influencing endothelial morphometry by image analysis of corneas stored in organ culture: coefficient of variation (CV) in cell area and percentage of hexagonal cells. Methods. The endothelium of 505 of the 559 corneas consecutively stored at the eye bank was routinely analyzed using the Sambacornea analyzer (Tribvn) on three large-field images of 750x1000 µm, obtained after osmotic dilation of the intercellular spaces with 0.9% sodium chloride. Analysis was done on at least 300 cells. The quality of the three-image set was graded 'poor', 'average' or 'good' by an independent observer. The studied parameters were: donor age and gender, lens status, storage time, intrinsic quality of captured images. Statistics: non-parametric tests. Results. Image analysis was possible with 504 of the 505 assessed corneas. Donor age was significantly correlated with endothelial cell density (r=-0343), CV (r=0.221) and hexagonality (r=-0.314) (p<0.001 for the three). Image quality significantly influenced these three parameters. Endothelial cell density (ECD) and hexagonality decreased parallel to image quality, while CV increased. For the 258 corneas assessed twice (on average at Day+4 then D+14) ECD, CV and hexagonality decreased during storage. Conclusion. Despite the sometimes mediocre quality of the transmitted light microscopy images, endothelial parameters supplied by the analyser are clinically reliable, because variations similar to those long known in specular microscopy were found. Endothelial morphometry (CV and hexagonality) is liable to provide further information on the endothelial function of the graft tissue, perhaps particularly for grafts of borderline ECD, close to the discard threshold.