Ocular surface mucosa and tear film (OSM/TF)

The ocular surface mucosa and tear film represent a complex physiological system that maintains the health, comfort, and optical quality of the eye (StatPearls, 2023). The tear film is a dynamic structure traditionally described as having three primary layers: an outer lipid layer that prevents evaporation, a middle aqueous layer containing nutrients and antimicrobial proteins, and an inner mucin layer that ensures the tear film adheres to the corneal epithelium (NIH/NEI, 2023). This system acts as the primary refractive surface of the eye and provides a critical barrier against environmental pathogens and mechanical friction (TFOS DEWS II, 2017). In conditions like Dry Eye Disease (DED), the homeostasis of this system is disrupted, leading to hyperosmolarity, inflammation, and potential damage to the ocular surface (PubMed, 2021). Pharmacological treatments for this system include lubricants to replace missing components, anti-inflammatory agents like cyclosporine to address underlying immune responses, and novel lipid-stabilizing drops to reduce evaporative loss (FDA, 2023).

Other names

Precorneal tear filmLacrimal functional unitOcular surface unitTear film trilayer

Therapeutic agents target this system by supplementing tear volume, stabilizing the lipid layer to prevent evaporation, reducing T-cell mediated inflammation, or stimulating endogenous tear production via neural pathways.