Tear film optics

Question 1

What is the most anterior surface of the eye?

Answer 1

Tear film

Question 2

What is the second most anterior layer of the eye?
3rd?
4th?
5th?
6th?
7th?

Answer 2

2-Epithelium
3- Bowman's membrane
4- stroma
5-Descemet's membrane
6-Endothelium
7 Dua's layer

Question 3

Dua’s layer is made of what type of collagen?

Answer 3

Type 1 collagen

Question 4

What layer regulates fluid in the stroma?

Answer 4

Endothelium

Question 5

This protects the cornea by providing a barrier against water, larger molecules and toxic substances.

Answer 5

Epithelium

Question 6

This consists mainly of randomly arranged collagen fibrils.

Answer 6

Bowman’s membrane

Question 7

This comprises 90% of corneal thickness and over 200 collagen lamallae. Collagen fibrils within each lamella run parallel to each other and the successive lamellae run across the cornea at angles to each other. (maintains an ordered transparency while enhancing mechanical strength.)

Answer 7

Stroma

Question 8

Is the basement membrane of the endothelial cells.

Answer 8

Descemet’s membrane

Question 9

_________ is single layered formed as hexagonal or honey combstructure, regulates fluid balance of cornea to maintain stroma at 78% hydration and retain transparency.

Answer 9

Endothelium

Question 10

Is located between the stroma and descemet’s membrane.

Answer 10

Dua’s layer

Question 11

Tear film is composed of _____, _____ and ____ layers.

Answer 11

oily, aqueous and mucous

Question 12

Optical power of the tear film is ______.

Answer 12

48.35 D

Question 13

The chief function of the tear film lipid layer. (2 things)

Answer 13

Provide a smooth surface for the cornea

Retard water evaporation