What is the Cornea?Closeup of an eye

The cornea is the clear, outermost layer of the eye and can be described as resembling a window into the interior of the eye.

What is the Cornea’s Function?

The main function of the cornea is to allow light to pass into the interior of the eye, so that it can reach the lens and then the retina. Other functions include protecting the eye from dust, germs and other harmful substances, as well as providing focus and regulating light coming into the eye in conjunction with the lens.

What is the Structure of the Cornea?

The cornea is made up of five distinct layers:

  • Epithelium: The outermost layer.
  • Bowman’s Layer: A transparent sheet made of collagen.
  • Stroma: Composed of 78 percent water and 16 percent collagen. This additional collagen gives strength, elasticity, and form.
  • Descement’s Membrane: The fourth layer which is comprised of different collagen than the stroma layer.
  • Endothelium: The innermost layer. This regulates excess fluid out of the stroma. These cells are essential to keeping the cornea clear.

Common Disorders or Diseases of the Cornea

  • Keratoconus
  • Fuchs’ Dystrophy
  • Corneal Infection
  • Dry Eye


View Video