Cornea:
- It is transparent.
- It replaces the sclera over anterior 1/6th of the eyeball.
- Its junction with sclera is called the sclerocorneal junction or limbus.
- It is more convex than the sclera
- The curvature diminishes with age.
- It is separated from the iris by a space called the anterior chamber of the eye
- It is avascular.
- Its is nourished by lymph which circulates in numerous corneal spaces and by the lacrimal fluid.
- It is supplied by branches of the ophthalmic nerve and the short ciliary nerves through ciliary ganglion.
- Pain is the only sensation aroused from the cornea.
Histology:
Cornea consists of these layers from before backwards.
1. Corneal epithelium - stratified squamous non-keratinised type.
2. Bowman’s membrane or anterior elastic lamina.
3. Substansia propria.
4. Descemet’s membrane or posterior elastic lamina
5. Simple squamous mesothelium.
Clinical Anatomy:
- Cornea can be grafted from one person to person, as it is avascular.
- Injury to cornea may cause opacities. These opacities may interfere with vision.
- Eye is a very sensitive organ and even a dust particle gives rise to pain.
- The anteroposterior diameter of the eyeball and shape and curvature of the cornea determine the focal point.
- Changes in these result in myopia or short-sightedness, hypermetropia or long-sightedness
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