AbstractThis study describes an in vitro preparation of isolated corneal endothelium, in which silver is used to stain the endothelial cell outlines. This permits high-power light microscopy and accurate measurement of individual cell characteristics. The photographed cell areas were measured with a planimeter and mean areas and cell densities were calculated. A total of 40 individual cells were measured from each of 11 guinea-pig corneas to give a mean cell area of 293 μm2and a mean cell density of 3413 cells/mm2. These figures are similar to findings for young human subjects. The accuracy and repeatability of the method were examined and an analysis of variance was carried out to ascertain the effects of interaction between zones and eyes within individual guinea pigs. Differences between eyes were rarely significant and peripheral cells were not found to be significantly different in area from central cells.