CPO FREE CPO Tonometry Principles and Procedures Questions and Answers 2

Question 1

A patient who recently underwent a vitrectomy with an intravitreal gas bubble is scheduled for tonometry. Which of the following is the most critical consideration when measuring their IOP?

Accepted Answer

The IOP can fluctuate dramatically with changes in atmospheric pressure, such as changes in altitude.

Answer

The patient's head must be positioned upright to ensure accuracy.

Answer

The presence of the gas bubble will artificially lower the IOP reading, requiring a correction factor.

Answer

Only a non-contact tonometer can be used to avoid disrupting the gas bubble.

Question 2

When performing Goldmann applanation tonometry on a patient with significant corneal scarring, the paraoptometric is most likely to encounter which issue?

Accepted Answer

Difficulty achieving clear, well-defined semicircular mires for an accurate measurement.

Answer

A falsely low and inconsistent IOP reading due to the soft nature of scar tissue.

Answer

An increased risk of corneal abrasion, even with proper technique.

Answer

Rapid dissipation of the fluorescein dye from the tear film.

Question 3

A paraoptometric performs a calibration check on a Goldmann tonometer. At the '2' setting (20 mmHg), the feeler arm only begins to move when the dial is turned past 2.4. When turned back, it only moves again when the dial is below 1.6. What is the most likely immediate cause of this inaccuracy?

Accepted Answer

An internal mechanism that requires lubrication.

Answer

A damaged or warped tonometer prism.

Answer

Incorrect positioning of the calibration weight bar.

Answer

A weak battery in the slit lamp illumination system.

Question 4

Which of the following tonometry methods is theoretically LEAST affected by corneal biomechanical properties like thickness, rigidity, and curvature?

Accepted Answer

Dynamic Contour Tonometry (DCT)

Answer

Goldmann Applanation Tonometry (GAT)

Answer

Non-Contact (Air-Puff) Tonometry (NCT)

Answer

Tono-Pen

Question 5

A patient with nystagmus requires an IOP check. Which type of tonometer would be most challenging to use effectively on this patient?

Accepted Answer

Non-contact tonometer

Answer

Rebound tonometer (e.g., Icare)

Answer

Tono-Pen

Answer

Pneumatonometer

Question 6

When measuring IOP on a patient who has undergone a penetrating keratoplasty (corneal transplant), what is a common finding when comparing Tono-Pen to Goldmann Applanation Tonometry (GAT)?

Accepted Answer

Tono-Pen tends to yield significantly higher IOP readings than GAT, especially at lower pressures.

Answer

Tono-Pen readings are generally identical to GAT readings.

Answer

Tono-Pen tends to yield significantly lower IOP readings than GAT.

Answer

Neither instrument can be used on a post-keratoplasty eye.