Keratocyte density and size in conscious humans by digital image analysis of confocal images

Purpose Confocal microscopy can give images of high magnification and resolution in undisturbed living tissue. It provides new information about the cellular structure of the cornea. Our aim was to measure the density, size and distribution of keratocytes. Methods Healthy cornea in four subjects was examined using tandem scanning confocal microscopy. Methods for digital analysis of images were developed. Results Keratocyte density in confocal cross-sections was greatest immediately under Bowman's membrane (maximum 800 cells/ mm 2 ) and decreased sharply towards posterior cornea (minimum 65 cells/mm 2 ). Cross-sectional cell size ranged from 78 to 211 µm 2 , but did not correlate with depth in the tissue. Conclusions Results are consistent with those of earlier work using histological and biochemical techniques in isolated tissue. The methods we have developed enable studies of ongoing processes in conscious humans and can be used to examine diseased tissue as well as the response to injury.