Normal human corneal cell populations evaluated by in vivo scanning slit confocal microscopy

Objective To evaluate cellular populations in healthy human corneas. Methods Sixty persons (120 normal eyes) were divided into three groups by age distribution. Group A, 20 persons (40 eyes), 5 14 years old; group B, 22 persons (44 eyes), 15 45 years old; group C, 18 persons (36 eyes), 46 70 years old. The images were recorded, cell morphology, densities and areas were measured. Results No statistically significant differences were found in cell densities or cell areas in any corneal layer between female and male persons, nor between right or left eyes No statistical differences between B and C group were found. No statistical differences were found in the densities and areas of superficial epithelial cells and basal epithelial cells among the 3 groups ( P 0 05) Only large subepithelial nerve endings were seen in Bowman′s membrane In each group, the difference in the keratocyte density of the anterior stroma from that of the posterior stroma was statistically significant ( P 0.01). The anterior and the posterior stromal cell densities in group A were statistically significantly different from those in either group B or C ( P 0.05). The endothelial cell areas and densities in group A were significantly different from those of either group B or C ( P 0.01). Conclusions Keratocytes and endothelial cells decrease in density with the increase of age. Scanning slit confocal microscopy is a useful tool for studying corneal cell morphology and density in vivo, and guidable for corneal disease and clinical diagnosis.