Air–tear and lipid–aqueous interfaces of the tear film

The air–tear and lipid–aqueous interfaces are the primary physical boundaries of the precorneal tear film, essential for maintaining ocular surface integrity and optical clarity. The air-tear interface is the outermost layer where the tear film lipid layer (TFLL) meets the environment; its primary role is to lower surface tension and provide a barrier against aqueous evaporation (Willcox et al., 2017). The lipid-aqueous interface is the transition zone between the hydrophobic lipids and the hydrophilic aqueous-mucin phase, stabilized by polar lipids like phospholipids and O-acyl-omega-hydroxy fatty acids (Cwiklik, 2016). Disruption of these interfaces, frequently observed in Meibomian gland dysfunction (MGD), leads to tear film instability and evaporative dry eye disease (Craig et al., 2017). Pharmacological treatments, such as perfluorohexyloctane or lipid-based artificial tears, aim to reinforce these interfaces to restore the tear film's protective properties and alleviate symptoms of ocular dryness (Sheppard et al., 2023).

Other names

Tear film interfacesOcular surface interfacesAir-tear interfaceLipid-aqueous interfaceTear film lipid layer (TFLL) interfaces

Stabilization of the tear film lipid layer to reduce aqueous evaporation and maintain low surface tension at the ocular surface.