Differential staining of ocular goblet cells.

Millipore filters were used to obtain sheets of cells from the ocular surface. Using Periodic Acid Schiff-haematoxylin the intracellular neutral mucus of the goblet cells stains a brilliant, bright pink and the cell nuclei dark blue making it possible to observe the epithelial cells and the goblet cell population. In certain ocular surface diseases the size of the PAS-haematoxylin staining goblet cell population is reduced, returning towards normal as ocular health improves. These observations had previously been interpreted as showing degeneration followed by regeneration of the goblet cells. However, Alcian blue stains an acidic mucus, which does not stain with PAS-haematoxylin. Acidic mucus containing goblet cells have been revealed using Alcian blue staining when added to the PAS stained cells in conditions that have previously been shown to have reduced goblet cell population when assessed by PAS-haematoxylin staining. This suggests that the staining properties of some of the goblet cells have changed. The extra goblet cells revealed by Alcian Blue staining makes the total of goblet cells present close to normal in numbers. Improved clearing methods and cytological preservation has revealed that there is also a population of goblet cells that do not stain with either technique. These observations must cast doubts on previous claims of reduced goblet cell population associated with some extraocular diseases.