COA Tonometry and Glaucoma 2

Question 1

Goldmann applanation tonometry (GAT) measures intraocular pressure by determining the force required to flatten a corneal area of what specific diameter?

Accepted Answer

3.06 mm

Answer

2.0 mm

Answer

4.5 mm

Answer

6.0 mm

Question 2

A patient's IOP is measured by GAT as 14 mmHg OD and 15 mmHg OS. The COA notes the corneal pachymetry is 490 microns OU. How should the COA interpret this?

Accepted Answer

IOP may be falsely low; thin corneas tend to underestimate true IOP with GAT

Answer

IOP is normal; thin corneas do not affect GAT readings

Answer

IOP may be falsely high; thin corneas overestimate true IOP with GAT

Answer

Pachymetry has no relationship to IOP measurement accuracy

Question 3

Which type of glaucoma is characterized by a narrow or closed iridocorneal angle that obstructs aqueous outflow?

Accepted Answer

Angle-closure glaucoma (ACG)

Answer

Primary open-angle glaucoma (POAG)

Answer

Normal tension glaucoma (NTG)

Answer

Congenital glaucoma

Question 4

What is the recommended first step before performing Goldmann applanation tonometry?

Accepted Answer

Instill a topical anesthetic and fluorescein

Answer

Dilate the pupil with tropicamide

Answer

Check that the slit lamp is set to white light

Answer

Ask the patient to remove contact lenses only if soft lenses are worn

Question 5

The optic nerve cup-to-disc ratio (CDR) is evaluated during ophthalmic assessment. Which CDR value is MOST suggestive of glaucomatous optic nerve change?

Accepted Answer

0.8 OD with inferior rim thinning

Answer

0.2 OU

Answer

0.3 OD, 0.3 OS

Answer

0.5 OU with symmetrical appearance

Question 6

Non-contact tonometry (NCT or 'air puff') measures IOP by analyzing what?

Accepted Answer

The time or force required for an air pulse to applanate the cornea

Answer

The light reflected from the fluorescein mires

Answer

The change in pupil diameter after air contact

Answer

The depth of the anterior chamber under pneumatic pressure