A gel of glycosaminoglycans lining the anterior and posterior chambers in man: histochemical evidence at light and electron microscopy levels.

A thin mucous layer covers the ciliary body and iris epithelium and becomes thicker in the anterior chamber where it covers the anterior surface of the iris, the chamber angle and corneal endothelial surface. It is especially thick at the chamber angle, where it adopts a meniscus shape with the concavity towards the anterior chamber. Cetylpiridinium chloride along with glutaraldehyde was used to precipitate this layer of mucous substance lining the anterior and posterior chambers of the human eye. The staining of the precipitate by cationic dyes suggests that glycosaminoglycans are main components. The specific characterisation with anti-hyaluronic acid monoclonal antibody labelled with colloidal gold reveals the presence of hyaluronic acid in the precipitate. Long unbranched hyaluronic acid molecules may form the skeleton of a gel able to trap and hold virtually any other macromolecule suspended in the aqueous humour. A possible role of such a gel in the regulation of aqueous humour outflow is discussed.