Purpose: Determination of the endothelial cell density (ECD) by eye banks is paramount in donor cornea qualification. Unbiased measurement avoids wastage and grafts with an increased risk of premature failure. Internal calibration of the counting method is essential, but external validation would add an extra stage in the assessment of reliability. In this respect, data published by the multicenter Cornea Donor Study (CDS) in 2005 is a reference. The aim of the study was to compare ECD determined within a single eye bank, which uses calibrated image analysis software designed for transmitted light microscopy images of organ cultured corneas, with the CDS data determined on specular microscopy images of corneas stored at 4°C.
Methods: ECD of consecutive corneas retrieved between 2005 and 2013 was determined after exposure to 0.9% NaCl. More than 300 ECs were counted on 3 fields of the central 8 mm. Endothelial cell boundaries were automatically drawn and verified by a skilled technician who performed all necessary corrections.
Results: Three thousand fifty-two corneas were analyzed, of which 48.5% donors were >75 years (CDS upper age limit). Between 10 and 75 years, the ECD varied according to donor age exactly in the same manner as in the CDS, but were consistently higher of 100 ± 25 cells per square millimeter (P < 0.001).
Conclusions: ECD determined by a computer-aided method from transmitted light microscopy images compares favorably with the American CDS reference series. The slight systematic difference on either side of the Atlantic Ocean could be due to (1) differences in counting principles and/or (2) higher shrinkage of the cornea caused by stromal edema in organ culture.
*Corneal Graft Biology, Engineering and Imaging Laboratory, EA2521, Federative Institute of Research in Sciences and Health Engineering, Faculty of Medicine, Jean Monnet University, Saint-Etienne, France;
†Department of Ophthalmology, University Hospital, Saint-Etienne, France;
‡Eye Bank of Saint-Etienne, Auvergne Loire Blood Center, Saint-Etienne, France;
§Department of Pathology, University Hospital, Saint-Etienne, France; and
¶Institut Universitaire de France, Paris, France.
Reprints: Gilles Thuret, Corneal Graft Biology, Engineering and Imaging Laboratory, EA 2521, SFR143, Jean Monnet University, 15, Rue Ambroise Paré, F 42023 Saint-Etienne Cedex 2, France (e-mail: email@example.com).
Supported in part by France's Agence Nationale pour la Recherche, TecSan 2012 program, CORRIMO 3D project, and by the French Health Ministry (PHRC IR, n1108035); and was promoted by the University Hospital of Saint-Etienne.
The authors have no conflicts of interest to disclose.
Received December 17, 2013
Accepted March 09, 2014