OcPhysio T2 Anticip

Question 1

What is the thickness of the cornea in the center?

Answer 1

0.52 mm

Question 2

What is the thickness of the cornea in the periphery?

Answer 2

0.71 mm

Question 3

What is the refractive index of the stroma?

Answer 3

1.376

Question 4

What happens to the cornea as thickness increases?

Answer 4

It approaches that of water (1.33).

Question 5

Is the cornea a minus lens or plus lens?

Answer 5

The cornea itself is a minus lens.

With the other parts in the environment, it becomes a positive lens.

Question 6

What is the total optical power of the cornea?

Answer 6

42.0D

2/3 of the eye’s total power.

Question 7

What happens to the cornea when it is submerged in water?

Answer 7

The corneal-air interface is destroyed.
Changes in the refractive power of the eye occurs.
Image is blurred because outside water index and cornea index are closely related to each other.
Use goggles to avoid blurriness.

Question 8

Is transparency is a static or dynamic process?

Answer 8

Dynamic.
We see obtaining nutrients and changes n oxygen, CO2, pH, and other metabolites needed to maintain the cornea’s transparency.

Question 9

What happens when there is random arrangement of collagen fibrils in the ground substance?

Answer 9

90% of incident light is scattered and transmitted.

Question 10

What is Maurice’s Lattice Theory

Answer 10

Collagen fibrils arranged in a regular lattice similar to a stack of diffraction gratings.

Question 11

What are the angles of the lattices determined by?

Answer 11

Ratio of the spacing of the scattering elements to the wavelength of the light.

Question 12

What gives you a zero order?

Answer 12

If the ratio of the scattering elements is greater than the wavelength of the light.
This is what we want.

Question 13

What are glycation cross links good for?

Answer 13

Enhance mechanical properties of fibrils.
This makes them stiffer, stronger, and tougher.
If too much, can make fibrils brittle and not function

Question 14

What is the most common collagen type in the cornea?

Answer 14

Type I

Question 15

What is the definition of heterotypic?

Answer 15

Composing of two or more collagen molecules.

TYPE I

Question 16

What is the first and second most popular collagen types in the cornea?

Answer 16

1. Type I

2. Type IV

Question 17

What adds to the transparency of the cornea?

Answer 17

Highly uniform small size and highly uniform small interfibrillar spaces of the fibrils.

Question 18

Is the anterior or posterior part of the stroma smaller?

Answer 18

Anterior

Question 19

Are keratocytes located more in the anterior part of the cornea or the posterior part?

Answer 19

Anterior

Question 20

What are the functions of the keratocytes?

Answer 20

Matrix turnover
Intracorneal communications
Glycogen storage
Interlamellar tethering
Wound healing by producing new matrix

Question 21

What are the two components for proteoglycans?

Answer 21

Core protein

GAG - glycoasminoglycan

Question 22

What are the functions of proteoglycans?

Answer 22

Provide tissue volume (fill up space, absorb H2O)
Maintain spatial order of collagen fibrils
Resist compressive forces
Give viscoelastic properties to the tissue
Regulate collagen fibril assembly.

Question 23

What are the two types of GAGs found in the corneal stroma?

Answer 23

Keratan

Dermatan.

Question 24

Which GAG structure is more abundant in the anterior corneal stroma?

Answer 24

Dermatan sulfate

Question 25

Which GAG structure is preferred in oxygen rich environment?

Answer 25

Dermatan

Keratan uses an alternate metabolic pathway

Question 26

Which GAG structure is more efficient at holding water?

Answer 26

Dermatan.
It absorbs more water than keratn.
Dermatan is good in the front because it prevents H2O from evaporating.

Question 27

Why is scattering of light minimal in the cornea?

Answer 27

Because the cornea is thin.