COT Visual Field Testing 5 — Questions and Answers
Question 1: When performing visual field testing on a patient with significant ptosis, which corrective measure should the technician take?
- Patch the ptotic eyelid closed
- Tape the upper eyelid to prevent artifact from lid droop (Correct answer)
- Reposition the patient's chin lower in the bowl
- Increase the background luminance of the perimeter
Correct answer: Tape the upper eyelid to prevent artifact from lid droop
Taping the upper eyelid prevents ptosis from obscuring the superior visual field and causing a false superior arcuate artifact during testing.
Question 2: Which of the following represents a macular threat when monitoring glaucoma patients with the Humphrey 24-2 program?
- Nasal step approaching the horizontal meridian
- Central scotoma encroaching within 5° of fixation (Correct answer)
- Arcuate scotoma in the superior field only
- Enlarged blind spot with no other defects
Correct answer: Central scotoma encroaching within 5° of fixation
When field defects approach within 5° of fixation, the 10-2 program should be added to monitor central field more precisely, as macular threat risks reading and driving vision.
Question 3: The Amsler grid primarily tests the central:
- 5 degrees of visual field
- 10 degrees of visual field (Correct answer)
- 20 degrees of visual field
- 30 degrees of visual field
Correct answer: 10 degrees of visual field
The standard Amsler grid tests the central 10° radius (20° total) of the visual field and is used to detect metamorphopsia and central/paracentral scotomas.
Question 4: A patient with advanced glaucoma completes a Humphrey 24-2 test showing only a small central island of remaining vision. Which additional test program is recommended to monitor this residual central field?
- 30-2
- 60-4 peripheral
- 10-2 (Correct answer)
- Full field 120-point screening
Correct answer: 10-2
The 10-2 program's denser 2° test grid within the central 10° provides better monitoring of the remaining central visual island in advanced glaucoma.
Question 5: What is the purpose of the foveal threshold measurement reported on a Humphrey Visual Field test?
- It calibrates the bowl luminance for the test session
- It provides a measure of central macular sensitivity that supplements the field test (Correct answer)
- It determines the correct background brightness for the stimulus
- It corrects for the patient's refractive error during testing
Correct answer: It provides a measure of central macular sensitivity that supplements the field test
The foveal threshold test measures the sensitivity at the very center of fixation (fovea), providing an additional data point about central macular function independent of the main field test.
Question 6: Which of the following visual field patterns is associated with a lesion in the temporal lobe affecting Meyer's loop?
- Superior homonymous quadrantanopia ('pie in the sky') (Correct answer)
- Inferior homonymous quadrantanopia
- Bitemporal hemianopia
- Monocular central scotoma
Correct answer: Superior homonymous quadrantanopia ('pie in the sky')
Meyer's loop carries inferior retinal fibers through the temporal lobe; damage here causes a contralateral superior homonymous quadrantanopia ('pie in the sky' defect).
Question 7: A patient who cannot maintain steady fixation due to nystagmus would be BEST assessed with which type of perimetry?
- Humphrey SITA Standard 24-2
- Goldmann kinetic manual perimetry (Correct answer)
- Frequency doubling technology (FDT) perimetry
- Short-wavelength automated perimetry (SWAP)
Correct answer: Goldmann kinetic manual perimetry
Goldmann kinetic perimetry performed by a skilled perimetrist can accommodate poor fixation by adjusting for eye movements, making it more practical than automated static methods for nystagmus patients.
COT Visual Field Testing 5
When performing visual field testing on a patient with significant ptosis, which corrective measure should the technician take?