Tear film lipid layer (TFLL) and corneal epithelial cell membranes

The tear film lipid layer (TFLL) and corneal epithelial cell membranes form the outermost protective barrier of the ocular surface. The TFLL, primarily composed of non-polar and polar lipids secreted by the Meibomian glands, functions to reduce the evaporation of the underlying aqueous tear layer and maintain a smooth optical interface for light refraction (Source: Willcox et al., 2017, "TFOS DEWS II Tear Film Report"). The corneal epithelial cell membranes, specifically the apical membranes of the superficial cells, are covered by a glycocalyx that promotes tear film stability and prevents pathogen entry (Source: Gipson, 2004, "The Ocular Surface"). In conditions like dry eye disease and Meibomian gland dysfunction, the integrity of these structures is compromised, leading to hyperosmolarity and inflammation (Source: Craig et al., 2017, "TFOS DEWS II Definition and Classification Report"). Pharmacological treatments such as perfluorohexyloctane (Miebo) directly target the TFLL to prevent evaporation, while various lubricants and osmoprotectants aim to stabilize the epithelial membrane and restore the ocular surface environment (Source: FDA, 2023, "Miebo Prescribing Information").

Other names

Ocular surface barrierPrecorneal tear filmTear film-cornea interface

Reduction of tear evaporation and stabilization of the ocular surface barrier.