CPO FREE CPO Visual Field Testing (Perimetry) Questions and Answers 2

Question 1

A visual field printout shows a dense superior defect that appears arcuate in shape on the pattern deviation plot.
However, the grayscale plot shows a distinct 'cloverleaf' or quadrantanopic pattern.
What is the most likely cause of this specific artifact?

Accepted Answer

Patient fatigue and inattention, leading to a high number of false negatives.

Answer

Incorrect trial lens placement creating a rim artifact.

Answer

A 'trigger-happy' patient with a high false positive rate.

Answer

Ptosis or a prominent brow obstructing the superior visual field.

Question 2

A patient with a known pituitary adenoma is undergoing visual field testing. Which of the following less common visual field defects would most specifically indicate that the tumor is exerting pressure on the *uncrossed* nasal retinal fibers at the optic chiasm?

Accepted Answer

Binasal Hemianopia

Answer

Bitemporal Hemianopia

Answer

Junctional Scotoma (of Traquair)

Answer

Homonymous Hemianopia with Macular Sparing

Question 3

Kinetic perimetry, such as Goldmann perimetry, is preferred over standard automated static perimetry in which of the following clinical scenarios?

Accepted Answer

Mapping the peripheral visual field boundaries in a patient with advanced retinitis pigmentosa.

Answer

Detecting subtle, early-stage glaucomatous changes near fixation.

Answer

Quantifying the depth of a known central scotoma for research purposes.

Answer

Screening for plaquenil toxicity which affects the parafoveal region.

Question 4

When performing perimetry on a patient who is wheelchair-bound and has difficulty maintaining a stable head position in a conventional automated perimeter, which modification is most critical to obtaining a reliable test?

Accepted Answer

Utilizing a virtual reality (VR) headset-based perimeter.

Answer

Using a larger stimulus size (Goldmann V) throughout the test.

Answer

Switching from a SITA-Standard to a SITA-Fast strategy to reduce test time.

Answer

Performing the test without a trial lens to reduce discomfort.

Question 5

The Visual Field Index (VFI) is a global index on a Humphrey printout that stages the total amount of visual field loss. How does it primarily differ from the Mean Deviation (MD)?

Accepted Answer

VFI is less affected by generalized depression, such as from a cataract, than MD.

Answer

VFI is expressed in decibels, while MD is a percentage.

Answer

VFI gives more weight to peripheral visual field points than central points.

Answer

VFI is only calculated for 10-2 tests, whereas MD is used for 24-2 and 30-2 tests.

Question 6

A patient with early glaucoma has a repeatable visual field test with fixation losses of 2/17, false positives of 1%, but false negatives of 35%. While this indicates inattention, what other clinical interpretation is possible for such a high false negative rate?

Accepted Answer

It can be an early indicator of significant, established visual field loss.

Answer

The patient has an unusually large physiological blind spot.

Answer

The test is unreliable and must be discarded without any interpretation.

Answer

The patient was not wearing the correct near-add correction.