The influence of technical procedures on cell countings in the rat corneal epithelium: a statistical analysis

We have performed a statistical analysis on cell counts from different areas of the rat corneal epithelium by using the number of cells per high power microscopical vision field (1250 x) as a unit. Each vision field consisted of 182 micron basal membrane. The number of vision fields varied from 29 to 39 in the horizontal and vertical diameter sections used. Only small variations were found in the number of cells from the different vision fields inside one single section. This confirm the extreme regularity of this epithelium. However, when comparing different sections, even from the same eye, the variations were much greater. Further, sections prepared for autoradiography showed a 10% reduction of the number of cells compared with the sections only stained with hematoxylin. A large proportion of the variation in the cell counts must be a result of the technical procedures, and is thus not an intrinsic property of the corneal epithelium. This conclusion may also be valid in cell counts from other epithelial structures.