Tear Film: The tear film is the thin layer of fluid that covers the surface of the eye, composed of three layers: the outer lipid layer produced by the meibomian glands, the middle aqueous layer produced by the lacrimal glands, and the inner mucin layer produced by goblet cells.
Sebaceous Glands: Sebaceous glands are specialized exocrine glands that produce an oily/waxy substance called sebum, which lubricates and waterproofs the skin and hair.
Lacrimal Glands: The lacrimal glands are the primary producers of the aqueous layer of the tear film, responsible for continuously secreting the watery component that helps maintain eye lubrication and wash away foreign particles.