Background and Basics

Question 1

What is the functional unit responsible for the production of Aqueous Humor?

Answer 1

Ciliary process

Question 2

What are the three types of ciliary body muscles

Answer 2

1. Longitudinal fibers (attache ciliary body to limbus)
2. Circular fibers (anterior and inner portions of CB)
3. Radial fibers (connect longitudinal and circular fibers)

Question 3

T/F: The CB is composed of muscles, vessels, epithelia lining CB and Autonomic nerve terminals.

Answer 3

True

Question 4

Why is it important that the ciliary process capillaries occupy the center of each process?

Answer 4

Because it brings the blood supply to the CB and allows for filtration mechanism to take place allows for AH production.

Question 5

What is the benefit of aqueous humor?

Answer 5

1. Serves as a source of antioxidants for corneal endothelium and the lens
2. Carries oxygen
3. Helps maintain shape of the globe
4. Serves as a shock absorber.

Question 6

Which Vitamin is found in greater amounts in aqueous humor than in blood?

Answer 6

Vitamin C is greater in AH

• Protein and Calcium are very low in AH
• *Hemoglobin is absent in AH

Question 7

T/F: Production of aqueous humor is greatest in the morning 8AM-noon

Answer 7

True (production is highest in the morning and lowest at night)

• 2.97 +/-0.77 microlitre/min (8am-noon) VS.
  1. 28 +/- 0.43 microlitre/minute (midnight - 6am)

Question 8

T/F: IOP is highest in the morning (8AM to noon).

Answer 8

False!

• IOP is highest at late night (midnight - 6am) despite production of aqueous humor being the lowest amount at this time.
• this is due to several other factors of physiology.

Question 9

T/F: The production of aqueous humor is an active process.

Answer 9

True. Two enzymes are involved in production of AH. they are;

• Na/K-ATPase
• Carbonic anhydrase
• **Inhibition of theses enzymes –> decrease AH production–> Glaucoma managment

Question 10

What are the two pathways of AH outflow?

Answer 10

1. Trabecular or conventional route (majority)

2. Uveoscleral or posterior route (can be upto 30%)

Question 11

If you want to decrease pressure right away, why would you not want to target the unconventional/uveoscleral route?

Answer 11

Because it is a little slower therefore you want to target the conventional route.

Question 12

T/F: the largest production of AH is through secretion.

Answer 12

True.

*the other methods of AH production are through Diffusion and Ultrafiltration.

Question 13

T/F: Both the total and trabecular outflow decline with age.

Answer 13

True.
Total - trabecular outflow = uveoscleral outflow
*there is no direct way of measuring uveoscleral outflow (it is a calculated amount)

Question 14

What are the two reasons why central vision is spared even in advanced cases of glaucoma?

Answer 14

1. The fibers intermingle with other fibers

2. Macula has a disproportionate amount of fibers given to it.