Comparison between manual count of the endothelial cells in donor corneas and computer-aided automatic count

Background: The evaluation of the endothelial cells is the most important criterion for assessing human donor corneas. The number, morphology and the vitality of the endothelial cells are decisive for the transparency of a cornea. The study has the following aim: to verify whether there is any difference between the manual and the automatic count of the cells by means of the NAVIS(R) system. Material and Methods: Both methods were performed on 57 corneas of 35 patients. A photo was taken for the manual count by a microscope at 40-fold enlargement and was printed for further analysis. A grid was applied to this photo and the number of the endothelial cells was projected by a multiplicator to one square millimeter. For the automatic evaluation a picture was made with 20-fold microscopic enlargement; the examiner chose an area to be analysed. There the count of the cells was controlled by software and directly projected to one square millimetre. This was followed by a manual correction. The measurement data were statistically evaluated. Results: No statistically significant difference was found between the manual and automatic counts. Conclusion: The manual count of the endothelial cells can be replaced by software-controlled automatic analysis and count.