Cornea

Question 1

What is the cornea’s index of refraction?

Answer 1

1.376

Question 2

The cornea composes what % of the total refraction of the eye?

Answer 2

70%

Question 3

What are the 5 layers of the cornea?

Answer 3

• Epithelium
• Bowman’s layer
• Stroma
• Descmet’s membrane
• Endothelium

(from front to back)

Question 4

What is the diameter of the cornea?

Answer 4

Horizontal 11.5mm and Vertical 11.2mm

Question 5

What is the Anterior refractive power?

Answer 5

+48.8D

Question 6

What is the Posterior refractive power?

Answer 6

-5.8D

Question 7

What is the total refractive power?

Answer 7

43.00D

Question 8

Epithelium

Answer 8

• Outer layer of the cornea.
• Ist line of defense
• 10% of cornea’s thickness (5-6 cells thick)
• Regenerates about every 2 weeks
• Regeneration helps it maintain its transparency

Question 9

Bowman’s layer

Answer 9

Outer, condensed portion of the stroma

Question 10

Stroma

Answer 10

• Middle layer composing 90% of the corneal thickness

- Made up of collagen layers called lamellae

Question 11

Lamellae

Answer 11

Collagen layers in the stroma that make right angles to each other. This pattern helps the cornea remain transparent by allowing light to enter the eye without being obstructed.

Question 12

Descmet’s membrane

Answer 12

Secreted by the Endothelium

Question 13

Endothelium

Answer 13

• Composed of one thin layer of hexagonal cells (endothelial mosaic)
• removes excess moisture from the eye, maintaining clarity, through deturgescence

Question 14

Limbus

Answer 14

• The transitional zone between the cornea and sclera

- Approximately 1mm thick