Concerning the symmetry of the 'hexagonal' cells of the corneal endothelium.

Modeling studies are presented to show how the figure coefficient and hexagon deviation index values decrease as a six-sided endothelial cell is systematically distorted from a completely symmetrical geometric shape (a regular hexagon). By use of scanning electron micrographs of rabbit corneal endothelium and an analysis of published specular micrographs of rabbit corneal endothelium, it is shown that the six-sided cells are not necessarily very symmetrical. Such cells should thus be reported as six-sided cells rather than as 'hexagons' which carries the inherent risk of implying regularity (and thus supposed stability in a tesselated mosaic) of such cells.