What Is the Tear Film and Why Is It Important?

Healthy eyes are continuously covered by a tear film that consists of 3 layers:

  • The outer, or lipid, layer is secreted by glands located behind the lashes in the eyelids. This layer prevents the tear film from evaporating
  • The middle, or aqueous, layer is secreted by glands located behind the eye. This is the thickest layer, providing the eye surface with oxygen and nutrients
  • The inner, or mucin, layer is secreted by goblet cells present on the eye surface. This layer enables tears to “stick” to the eye

Tear film consists of 3 layers − lipid, aqueous and mucin

A stable tear film:

  • Protects and lubricates the eyes
  • Reduces the risk of eye infection
  • Washes away foreign particles
  • Keeps the surface of the eyes smooth and clear

What can happen if the tear film becomes unstable?

If your eyes don't create the right quality or quantity of tears, your tear film may become unstable. This can cause dry areas and irritation on your eye, which may develop into Chronic Dry Eye (CDE) disease.

If you have questions about Chronic Dry Eye, you need to talk with your eye doctor.