Tear film lipid layer and ocular surface cell membranes (TFLL)

The tear film lipid layer (TFLL) is the superficial layer of the tear film, primarily composed of lipids secreted by the Meibomian glands, which works in conjunction with the ocular surface cell membranes to maintain eye health (Willcox et al., 2017). Its primary biological function is to provide a smooth optical surface and act as a barrier that prevents the evaporation of the underlying aqueous tear layer (Willcox et al., 2017; Butovich, 2011). Ocular surface cell membranes, including the glycocalyx of the corneal epithelium, provide the necessary hydrophilicity for tear film adherence and stability (Willcox et al., 2017). Dysfunction in this system, often due to Meibomian gland dysfunction (MGD), leads to evaporative dry eye disease, characterized by tear film instability and ocular surface inflammation (Nelson et al., 2017). Pharmacological agents like perfluorohexyloctane target the TFLL by mimicking its evaporative-resistant properties, thereby restoring the integrity of the ocular surface (FDA Miebo Label, 2023). These treatments aim to alleviate symptoms such as dryness, irritation, and visual fluctuations by stabilizing the lipid-aqueous interface (FDA Miebo Label, 2023; Nelson et al., 2017).

Other names

Tear film lipid layerPrecorneal lipid layerOcular surface membranesMeibum layerPre-ocular lipid film

Stabilization of the tear film by forming a protective layer at the air-liquid interface to reduce evaporation and lower surface tension.