Urgent Need for Normalization of Corneal Graft Quality Controls in French Eye Banks

Abstract

This audit highlights the unacceptable lack of reliability of manual ECD assessment in French eye banks. This surely indicates the delivery of poor quality corneas for graft in certain centers and wastage in others. We urgently advocate normalization of French counting methods. This may require upgrading to a computer-aided method.

Automatic estimation of endothelium cell density in donor corneas by means of Fourier analysis

“…This latter value is within the maximum range of variation of manual averages (26%) and well within that of single manual densities (40%). This range of variability of manual densities appears rather large, but is actually even lower than what another group found in a multi-centre study, reporting differences of up to 51% between technicians from the same eye bank and of 82% between technicians from different eye banks (THURET et al, 2004). in addition, it expresses the total variability in manual cell density estimation on a given cornea, which is due to many different factors, as mentioned above.…”

Reproducibility of Endothelial Assessment during Corneal Organ Culture: Comparison of a Computer-Assisted Analyzer with Manual Methods

“…7,9 Unacceptable interbank and intrabank variations in manual counts noted in our previous studies were attributed to improper microscope calibration and differences in counting strategy. 4,5 Both factors were neutralized in the present study because, for the manual counts, images taken after appropriate microscope calibration were analyzed by all observers with the same fixed-frame counting strategy. For computer-assisted analysis, the same three images were used, as was the touched-up mode, whose exactness had already been established.…”

“…This was attributed mainly to a lack of microscope calibration and the use of different counting strategies. 4,5 Computer-assisted analyzers with digitized light microscopy images have been used for endothelial evaluation since the mid-1980s. 6 -8 Recent years have seen the introduction of digital image acquisition and improved computer algorithms, which allow a reliable estimation of endothelial parameters.…”

Preservation of Human Cornea

“…According to the 2010 European Eye Bank Association Directory report [15], the minimum ECD varies between eye banks, with almost 70% having a minimum of 2,000 cells/mm 2 and the others having minima ranging from 2,100 to 2500 cells/mm 2 . Given the emphasis placed on donor ECD, the reliability of ECD estimates is clearly an important consideration [16][17]. Modelling the change in ECD after corneal transplantation suggests that a cornea with an ECD of 2,200 cells/mm 2 should retain sufficient endothelial cells to maintain corneal transparency for at least 25 years [4].…”