The effects of extended-wear hydrophilic contact lenses on the human corneal epithelium.

We used wide-field color specular microscopy of the human corneal surface to study the morphologic changes that occur under extended-wear contact lenses. There was a shift in the frequency distribution of surface cells by size to larger cells, suggesting a prolonged residence time on the ocular surface. Other abnormalities included retained desiccated mucin, coarse mucus plaques, and palisading of cells.