Tear film and ocular surface – non-specific physical interface (TF/OS)

The tear film and ocular surface represent a complex, multi-layered physical interface essential for maintaining ocular health and visual clarity. This interface is traditionally described as a trilayered structure—comprising an outer lipid layer, a central aqueous layer, and an inner mucin layer—though it is now often viewed as a complex mucoaqueous gradient (TFOS DEWS II, 2017 [1]). Its primary biological functions include providing a smooth refractive surface for vision, lubricating the ocular surface to minimize friction during blinking, and serving as a protective barrier against environmental pathogens and mechanical trauma (StatPearls, 2023 [2]). In conditions like Dry Eye Disease (DED), the integrity of this interface is disrupted, leading to tear film instability, hyperosmolarity, and subsequent inflammation of the ocular surface (National Eye Institute, 2023 [3]). Therapeutic interventions targeting this non-specific interface, such as artificial tears and lubricants (e.g., Hyaluronic acid, Carboxymethylcellulose), act through physical mechanisms like hydration, lubrication, and stabilization of the tear layers rather than binding to a specific molecular receptor (TFOS DEWS II Management and Therapy Report, 2017 [4]). These treatments aim to restore the homeostatic environment of the ocular surface and protect the underlying corneal epithelium from desiccation and damage (PubChem, 2024 [5]).

Other names

Precorneal tear filmOcular surface interfaceTear filmTear film layers

Physical lubrication, hydration, and stabilization of the tear film layers to reduce friction, lower tear osmolarity, and protect the corneal epithelium.