Specular microscopic observation of normal human corneal epithelium

The authors analyzed the specular microscopic appearance of normal corneal epithelium, with particular regard to four cell patterns previously identified in pathologic corneas. Corneal epithelia of 75 normal eyes were examined by specular microscopy using a special compound contact lens. There were no elongated or extra large cells, whereas 44.0% and 35.7% of the corneas showed central epithelial nuclei and irregular patterns, respectively. The mean epithelial cell area and corresponding mean coefficient of variation (CV) for each of the corneas were 595.6 +/- 98.8 microns 2 and 30.3 +/- 15.3%, respectively. The values for the endothelium were 325.7 +/- 48.4 microns 2 and 33.6 +/- 6.3%, respectively. Although there was a significant Pearson correlation (r = 0.50, P less than 0.01) between mean endothelial cell area and age, none existed (r = 0.19, P greater than 0.05) between mean epithelial cell area and age, even though there was a relationship (r = 0.35, P less than 0.01) between the mean cell areas themselves. There were no significant relationships among the CV of the epithelium, that of the endothelium, and age. This study presents a powerful new technique and baseline data by which to assess normal corneal epithelium and any aberration.