Lec 8

Question 1

Where is aq humor produced?

Answer 1

CB epith

Question 2

What enzymes control aq humorproduction?

Answer 2

Carbonic anhydrase, Na/K-dependent ATPase

Question 3

Describe: conventional route of aq humor outflow

Answer 3

aq humor passes through TM into Schlemm’s canal. Exits through collector channels into venous system; 70%+ of outflow

Question 4

Describe: Unconventional route of aq humor outflow

Answer 4

Aq humor passes through uvealscleral pathway: through iris root uveal meshwork and anterior face of ciliary muscle –> through suprachoroidal space and out through slera; 30% or less of outflow

Question 5

What is the most significant factor in the etiology of increased IOP?

Answer 5

interference with aqueous outflow

Question 6

T/F: Prostaglandins increase outflow; Carbonic anhydrase inhibit production of aq humor

Answer 6

True

Question 7

What % of pts dev glauc despite normal IOP?

Answer 7

30%

Question 8

What is the diameter of the circular zone of applanation?

Answer 8

3.06 mm

Question 9

What is the area of applanation?

Answer 9

7.3542 mm^2

Question 10

Applanation tonometry has what standard dev of error?

Answer 10

+/- 0.5 mm Hg

Question 11

What assumptions did Hans Goldmann make when devising his tonometer?

Answer 11

avg corneal thickness of 20 microns, resistance to deformation is cancelled out by surface tension generated when the area applanated has a diameter of 3.06mm

Question 12

GAT: 1 g of force needed to flatten an an area equal to what? which means the diameter is what?

Answer 12

7.3542 mm^2, 3.06 mm

Question 13

What are indications for punctal occlusion?

Answer 13

Preg, very young, HTN, when using multiple drops (so pt doesn’t taste it), very dark brown eyes

Question 14

Drops have been instilled. What happens every time a pt blinks?

Answer 14

meds go into the lac canal/sac and increase systemic absorpton

Question 15

Fluress vs Flurox. Which has benoxinate?

Answer 15

Fluress has benoxinate

Question 16

What is the wetting agent in Fluress?

Answer 16

Povidome

Question 17

How many degrees of separation are between the A & O (or red & white lines) of a tono probe?

Answer 17

43 deg

Question 18

K readings: 40 @ 050, 42.50 @ 140. Where would you line up the Red line of the tono probe?

Answer 18

050

Question 19

If you see limbal glow, have you made contact with the cornea?

Answer 19

Yes

Question 20

Mires that are too thick will give an artificially ___ IOP. Mires that are too thin will give an artificially ____ IOP.

Answer 20

high, low

Question 21

lateral motion of mires is caused by what phenomenon? When do you “read” the mires?

Answer 21

Pulsating mires; when interlocked at the highest point

Question 22

What are cautions/contraindications for Contact Tono?

Answer 22

allergy to all anesthetics, pts with recurrent corneal erosion, Bullous keratopathy, Corneal hydrops (Keratoconus), corneal abrasions that aren’t healed, signif corneal edema

Question 23

What doesn’t wash out with disinfection, but does wash out with water?

Answer 23

Hep B virus DNA

Question 24

What is the single most effective means of avoiding the risk of transmitting or acquiiring infections during an eye exam?

Answer 24

hand washing

CDC rec’s immediately before and after contact with pt