Which glands are responsible for secreting the aqueous layer of the tear film?

The lacrimal glands are primarily responsible for secreting the aqueous layer of the tear film. This layer is crucial for maintaining moisture on the surface of the eye, providing lubrication, and helping to wash away debris and irritants. The main function of the lacrimal glands is to produce tears that contain water, electrolytes, and proteins, which are essential for the health of the ocular surface.

Tears produced by the lacrimal glands serve multiple purposes, including nourishment of the cornea, providing a smooth optical surface, and aiding in the prevention of infection through antimicrobial properties. This aqueous layer works in conjunction with the oily layer secreted by the meibomian glands and the mucous layer secreted by conjunctival goblet cells to form a complete tear film that protects and lubricates the eye.

While meibomian and conjunctival glands also contribute to the overall composition of the tear film, they do not produce the aqueous layer. Meibomian glands secrete oils that reduce tear evaporation, and conjunctival glands contribute to mucus production. The tarsal glands are synonymous with meibomian glands in some contexts, primarily involved in oil secretion. Therefore, the lacrimal glands are the correct answer, as they