Toward a quantitative analysis of corneal endothelial cell morphology: a review of techniques and their application

Quantitative assessments of endothelial cell density, area, and shape have become increasingly common over the last 10 years. Despite the relatively widespread availability of instruments for in vivo (specular microscopy) or in vitro (scanning electron microscopy or histological techniques) assessment of the endothelial mosaic, little standardization of reporting of these characteristics has occurred. A comprehensive summary and review of the assessments of cell density in normal and pathological corneas, assessments of cell area (of its variance, coefficient of variation, polymegethism), and assessments of cell shape (pleomorphism, index of hexagonality, shape factors, figure coefficients, elongation index) is presented. An attempt is made to relate these numerous procedures and reporting methods by an objective critique both of the methods and of the many studies.