Quantitative analysis of endothelial mosaic pattern changes in anterior keratoconus.

The corneal endothelia of 21 eyes with anterior keratoconus and 15 eyes of age-matched controls were investigated with a specular microscope. Of the 21 eyes, 15 had definite keratoconus while six apparently normal fellow eyes were designated as latent. The corneal endothelial photographs were subjected to a computerized digitizer analysis of the area and shape of individual cells. The endothelium in keratoconus showed a significant increase in the extent of polymegethism (the coefficient of variation in cell area; 0.36 +/- 0.07) as compared with controls (0.24 +/- 0.03), with the mean cell area staying within normal limits. The relative frequency of hexagonal cells in keratoconus (50.5 +/- 5.7%) was significantly lower than that of controls (70.6 +/- 5.5%). Additionally, an increase of various cell shapes was noted, indicating that there was also a significant increase in cellular pleomorphism. In the latent group, alterations in cellular structure could not be detected by analysis of cell area when compared to controls. However, when these eyes were subjected to cell shape analysis and compared to fellow keratoconic eyes, both eyes showed similar pleomorphic characteristics. These results suggest that in the fellow eye in unilateral keratoconus, even when there are no ocular signs and symptoms, diagnosis can be made early with specular microscopy and computerized cell shape analysis.