Cornea and Sclera (Chapter 3)

From the studyguide

What are the functions of the eyelids?

Protect the eye, spread tears, keep cornea moist, block light.

What are the functions of the pre-corneal tear film?

Keep cornea smooth/clear, protect from infection, provide oxygen/nutrients, wash away dirt.

What does lysozyme do?

Enzyme in tears that kills bacteria.

What are the four ways the cornea gets nutrients?

Tear film, aqueous humor, limbal blood vessels, nerve supply.

What are the three layers of the tear film and their purposes?

• Lipid layer: prevents evaporation.

• Aqueous layer: nutrients, oxygen, protection.

• Mucin layer: helps tears stick to cornea.

What are the five layers of the cornea (front to back)?

Epithelium, Bowman’s layer, Stroma, Descemet’s membrane, Endothelium.

Which corneal layer is the metabolic pump?

Endothelium.

Which corneal layer regenerates?

Epithelium.

Which corneal layer is the largest and has lamellar fibers?

Stroma.

Which corneal layer is very strong and acts as a barrier to infection?

Descemet’s membrane

Which corneal layer does not regenerate and will scar if scratched?

Bowman’s layer. .