The cornea forms the anterior one fifth of the fibrous tunic. It is transparent, colorless, and avascular. It is oval, the broad end being medial. The anterior surface is convex and more curved than the sclera. The posterior surface is concave and forms the anterior boundary of the anterior chamber. The margin joins the sclera where the sclera overlaps the cornea.
Structure
- Corneal epithelium lined stratified squamous epithelium.
- Lamina limitans anterior or Bowman’s membrane which is very thin and homogeneous.
- Substantia propria -lamellae of connective tissue with connective tissue corpuscles-the corneal corpuscles that are transparent.
- Lamina elastica or Descemet’s membrane– a thick, elastic homogeneous membrane. This lamina divides at the periphery into three divisions, the anterior part joins the sclera; the middle one gives attachment to the ciliary muscle and posterior division passes to the iris forming the ligamentum pectinatum iridis.
- Endothelium of squamous cells; this after lining the cornea is reflected over the iris.
Note
All the layers forming the cornea are transparent.
Blood Supply
Cornea is devoid of blood vessels. It derives nutrition from the superficial plexus of vessels.
Nerve Supply
Ciliary nerves.
