Meibomian glands secrete lipids that form which tear film layer?

• A. Lipid layer
• B. Aqueous layer
• C. Mucin layer
• D. Solid layer

Answer: (A)

Meibomian glands secrete lipids that form the outermost lipid layer of the tear film. This lipid layer reduces evaporation of the underlying aqueous layer, helps the tear film spread smoothly over the ocular surface, and provides a stable, even refractive surface for vision. The aqueous layer underneath is produced mainly by the lacrimal glands, and the mucin-containing layer that helps the tear film adhere to the corneal surface is produced by conjunctival goblet cells. Thus, the lipid layer is the correct choice.