Tear film muco-aqueous layer

The tear film muco-aqueous layer is not a single molecular target but rather a functional component within the precorneal tear film. It consists primarily of water (~98%), salts, proteins, growth factors, and both membrane-associated and soluble mucins such as MUC5AC. The muco-aqueous phase forms more than 90% of the total tear volume and plays essential roles in hydrating and lubricating the ocular surface, maintaining optical clarity for vision, protecting against infection by flushing away debris/noxious substances during blinking, and supporting epithelial health. Membrane-associated mucins contribute to wettability by forming a glycocalyx on corneal epithelial cells while soluble mucins secreted by conjunctival goblet cells are dispersed throughout this aqueous matrix to further enhance hydration/lubrication. Dysfunction or deficiency in this layer—such as reduced MUC5AC expression—is implicated in dry eye disease pathogenesis. While drugs like artificial tears aim to supplement this functionally critical compartment for symptomatic relief in dry eye syndromes, there is no specific "receptor" or "enzyme" that defines it as a classical therapeutic target.

Other names

Muco-aqueous layer of tear filmMucoaqueous phase of tear filmTear film mucogelPrecorneal tear film (muco-aqueous component)

Supplementation or stabilization of the muco-aqueous layer to restore hydration and lubrication in dry eye conditions