Ocular surface lipid bilayers and membrane-associated proteins

The ocular surface lipid bilayers and membrane-associated proteins constitute the primary protective barrier of the eye, consisting of the tear film lipid layer (TFLL) and the epithelial glycocalyx (Cwiklik, 2016). The TFLL, primarily composed of non-polar and polar lipids secreted by meibomian glands, serves to reduce tear evaporation and maintain a smooth optical surface (Craig et al., 2017). Membrane-associated proteins, specifically transmembrane mucins like MUC1, MUC4, and MUC16, form the glycocalyx which anchors the aqueous tear layer to the corneal epithelium and provides essential lubrication (Mantelli & Argüeso, 2008). Dysfunction in these components is a central driver of dry eye disease (DED) and meibomian gland dysfunction (MGD), leading to tear film instability, hyperosmolarity, and ocular surface inflammation (Craig et al., 2017). Therapeutic agents such as perfluorohexyloctane target the lipid bilayer to prevent evaporation, while others like diquafosol or rebamipide aim to restore the mucin-rich glycocalyx (FDA Miebo Label; Mantelli & Argüeso, 2008). Additionally, membrane proteins like LFA-1 are targeted by drugs like lifitegrast to interrupt the inflammatory cycle associated with ocular surface damage (FDA Xiidra Label). As the initial site of contact for topical ophthalmic drugs, the integrity and biophysical properties of these membranes are critical for drug penetration and therapeutic efficacy.

Other names

Tear film lipid layerOcular surface glycocalyxCorneal epithelial cell membraneTFLL

Stabilization of the tear film lipid layer to reduce evaporation, enhancement of mucin secretion to restore the glycocalyx, and competitive inhibition of cell-surface receptors to reduce inflammation.