The human limbus. A scanning electron microscopic study
J. V. Greiner, H. I. Covington and M. R. Allansmith
Fourteen human limbal biopsy specimens were obtained from seven normal
subjects. The epithelial surface was examined by scanning electron
microscopy. Epithelial cell surfaces varied greatly in shape and size, and
mosaics of three- to six-sided irregular polygons were formed. Microvillar
borders of cells were distinct. Cell sizes ranged from 3 to 20 micron
across. Light and dark cells were present and randomly distributed. A few
cells were covered with microplicae; the remainder of the cells were
covered with microvilli. Intercellular crypt openings measuring 1 to 10
micron in diameter were distributed randomly over all specimens. These
openings were believed to be related to goblet cells. Many openings were
plugged with what appeared to be mucus. Many surface-level intercellular
structures were present; they corresponded in diameter to the surface
openings. The human limbal epithelium varies from both the upper tarsal
conjunctiva and the cornea.
