Abstract
The endothelium of the normal corneas of 67 human subjects was studied in vivo with the specular microscope in order to quantify the method as a means of sampling the cell density of the tissue. It was found that (1) axial cell counts of the endothelium are reproducible in the same cornea after an interval of time; (2) the cell counts of the centre and periphery of the same cornea are similar; (3) the axial cell counts of pairs of eyes are similar; and (4) there is a gradual reduction of cell number with increasing age. The significance of these data is discussed.