Cornea

Definition

The cornea is the transparent, dome-shaped surface that covers the front of the eye. It plays a crucial role in focusing light onto the retina for clear vision.

5 Must Know Facts For Your Next Test

1. The cornea is composed of five layers: the epithelium, Bowman's layer, stroma, Descemet's membrane, and endothelium.
2. It is avascular, meaning it does not contain blood vessels; it receives nutrients from tears and the aqueous humor.
3. The cornea contributes approximately 65-75% of the eye's total focusing power.
4. Damage to the cornea can result in impaired vision or blindness if not treated properly.
5. The cornea also serves as a barrier against dirt, germs, and other particles that can harm the eye.

Review Questions

• What are the five layers of the cornea?
• How does the cornea receive nutrients despite being avascular?
• What percentage of the eye's total focusing power is attributed to the cornea?

Related terms

Retina:

The light-sensitive layer at the back of the eye that converts light into neural signals.

Lens:

A transparent structure behind the iris that helps focus light onto the retina.

Aqueous Humor: The clear fluid in the eye that provides nutrients to avascular structures like the lens and cornea.