Demonstration of the human ocular surface glycocalyx by transmission electron microscopy

The aim of this work was to demonstrate the ultrastructural appearance of the human ocular surface glycocalyx in normal subjects. Conjunctival tissue specimens from 7 normal subjects were obtained by bulbar conjunctival biopsy, and examined by transmission electron microscopy. The free surface of the apical conjunctival epithelial cells was characterized by the presence of microvilli. All specimens showed the presence of an ocular surface glycocalyx, which appeared as a continuous, fine network of filamentous electron-dense material associated with the apical cell membrane. This filamentous layer exhibited a higher density on the tips of the microvilli and extended among the microvilli, forming an extrinsic cell surface coat. Examination of the ultrastructural morphology of the apical conjunctival epithelium by transmission electron microscopy may prove a useful tool in the diagnostic and investigative evaluation of healthy and diseased conjunctivas.