What are the three layers of the tear film?

The three layers of the tear film consist of the lipid layer, the aqueous layer, and the mucin layer.

The lipid layer is the outermost layer and its primary role is to reduce tear evaporation and provide a smooth surface for the tears, enhancing the stability of the tear film. This layer is produced by the meibomian glands located in the eyelids.

The aqueous layer is the middle layer and is the thickest among the three. It contains the majority of water in the tear film and is responsible for hydrating the eye, providing nutrients, and containing antimicrobial proteins that help protect against infection. This layer is produced by the lacrimal glands.

The mucin layer is the innermost layer that interacts with the surface of the eye (cornea and conjunctiva) to help spread the tears evenly across the surface and keep it moist. This layer is essential for proper adhesion of the tears to the eye surface.

This tri-layer structure is crucial for maintaining ocular health, providing comfort, and ensuring clear vision.