Set Descriptors for Visual Evaluation of Human Corneal Endothelia

Images of corneal endothelium obtained from specular microscopy are of great importance in the evaluation of the corneal endothelium status. Several commercial tools provide some numerical descriptors to characterize these images in terms of cell density, hexagonality, and some descriptive statistics of the cell areas. However, it is a too simple analysis that only detects severe abnormal endothelia with many irregular and large cells. Detection of subtle abnormalities needs a more refined analysis. This paper proposes a shape-size descriptor based on some modified versions of the geometric covariogram. This descriptor is presented as a valid alternative to the classical analysis that provides a reliable, visual, and easy evaluation of the corneal endothelium. Control images of normal endothelia can be used to classify a given image as normal or abnormal with respect to these controls by means of a graphical test.