Normal features of superficial nondesquamating cells of the rabbit corneal epithelium assessed by scanning electron microscopy.

OBJECTIVE

To quantitatively assess surface features of corneal epithelial cells with particular emphasis on regional differences in cell size or shape.

ANIMALS STUDIED

Female New Zealand White rabbits, aged 11-12 weeks.

PROCEDURES

Animals were exposed to a light : dark cycle of 14 : 10 h for 2 weeks and then the corneas prepared for scanning electron microscopy (SEM) at 1500 h. Images were taken at central location (C), mid-periphery (MP), and periphery (P) of the cornea. On prints at 5000x, cell-cell borders were marked, and long (L) and short (S) dimensions measured, and the surface ring-shaped features outlined and counted.

RESULTS

Across the epithelial surface cells had from 3 to 11 bordering cells (sides), with 5-sided cells being more common (mean 32.7 +/- 11.3%, SD). L dimensions averaged 26.7, 30.9, and 33.9 microm at the C, MP, and P locations, while S dimensions were 18.5, 21.8, and 24.0 microm, respectively. The L : S ratio was1.523, with averages of 1.567, 1.501, and 1.487 at the three locations. Using an averaged cell dimension, cell density was estimated and found to be 7376, 4405, and 3071 cells/mm(2) at C, MP, and P locations. Almost all cells were decorated with ring-shaped features (craters), with the number increasing in relation to cell size and were much higher on more peripheral cells.

CONCLUSIONS

The non-exfoliating corneal epithelial surface is composed of flat polygonal cells often with 5-sides cells, which are progressively larger towards the peripheral cornea and more decorated with ring-shaped features.