Cornea

CORNEA is the transparent layer on the front part, covering the eye. An intrinsic physiological requirement for cornea is paramount for the maintenance of its transparency to ensure proper vision. The shape of cornea is best represented by an ellipse, which progressively flattens in curvature from centre to edge.

  • No blood vessels.
  • Consist of 22% solid and 78% water.
  • Cornea height ~10.6mm-11mm
  • Cornea width ~11.8mm-12mm
  • Consist of 5 layers; cornea epithelium, Bowman’s layer, stroma, Descement’s membrane and endothelium.

Functions of cornea to the eye are:

  • creating smooth refractive surface – in order for image to focus properly on retina
  • permeability barrier
  • barrier entry of pathogen – shield the eye from harmful germs, dust and other foreign matter

Outer most layer of cornea, epithelium, has a turn overtime of 7 days. Thus, at times, cease wearing contact lens for a week will enable proper cells regeneration.

Corneal sensitivity will reduce with:

  • age
  • contact lens wear
  • hormone changes
  • blue iris is more sensitive than brown iris
  • lowest sensitivity in the morning and increase sensitivity throughout the day
  • nerve atropy (nerve dying)

P.S. Without cornea, you will be blind.

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