Tear film – Layers and formation

Tear film is composed of 3 layers. They are:

• Mucinous layer
  • Innermost layer
  • Mucin is secreted by conjunctival goblet cells and glands of Manz
  • It transforms the corneal surface from hydrophobic to hydrophilic
• Aqueous layer
  • Middle layer
  • Secreted by the main and accessory lacrimal glands
• Lipid layer
  • Outermost layer
  • Secreted by meibomian glands
  • Prevents evaporation of water
  • Lubricates the eyelids