Cornea

Dr Craig Hacking and Dr Verlyn Yang et al.

The cornea forms the fibrous layer of the anterior portion of the eye. It functions to refract light entering the eye. 

  • location: anterior one-sixth of the eyeball
  • blood supply: avascular
  • innervation: long ciliary nerves 
  • relations: continuous with the sclera posteriorly and covered by the conjunctiva anteriorly

Anteriorly, the cornea is a convex structure covered by bulbar conjunctiva. The curvature is greater than that of the rest of the eyeball covered by the sclera. Posteriorly, the cornea is concave and round. It is made up of 5 layers. 

Transparency of the cornea is due to the regular arrangement of the collagen fibrils in lamellae in the stroma. 

The cornea is largely avascular. The peripheral parts are related to capillaries from the anterior ciliary arteries. It is nourished by the aqueous humour and gaseous exchange occurs through the tear film. 

The cornea is an alymphatic organ. 

Densely innervated by the long ciliary nerves, branch of the nasociliary nerve, which is derived from the ophthalmic division of the trigeminal nerve.

Histologically, the cornea is made up of 5 layers (from superficial to deep):

  1. epithelium
  2. Bowman's membrane 
  3. stroma (substantia propria)
  4. Descemet's membrane
  5. endothelium 

Imaging of the cornea can be performed by a number of techniques, including:

  • corneal topography: characterises the shape of the cornea qualitatively and quantitatively
  • anterior segment optical coherence tomography (AS-OCT): produces a cross-section image of the cornea and other anterior segment structures
  • ultrasound biomicroscopy: high-frequency and high resolutions are required

CT and MRI are not performed for imaging of the cornea.

Derived from the Latin cornea tela (“horny tissue”) and from cornu (“horn”).

  • astigmatism: refractive error due to aspheric or uneven cornea curvature
  • keratoconus: most common corneal ectasia, is a progressive corneal condition characterized by central thinning and steepening of the cornea
  • Fuchs endothelial dystrophy: non-inflammatory dystrophy of the cornea
  • keratitis
Anatomy: Head and neck
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Article information

rID: 63509
System: Head & Neck
Section: Anatomy
Tag: anatomy, eye
Synonyms or Alternate Spellings:

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