COT Visual Field Testing 4 — Questions and Answers
Question 1: The 10-2 visual field test pattern is specifically designed to test points within what degree of fixation?
- 5 degrees
- 10 degrees (Correct answer)
- 20 degrees
- 30 degrees
Correct answer: 10 degrees
The 10-2 program tests a 10° × 10° grid centered on fixation with points spaced 2° apart, making it ideal for monitoring central field in conditions like macular degeneration or advanced glaucoma.
Question 2: Which of the following best describes the physiologic blind spot on a visual field test?
- A learned area of suppression near fixation
- An absolute scotoma approximately 15° temporal to fixation corresponding to the optic disc (Correct answer)
- A relative scotoma caused by the ora serrata
- A depressed area seen in patients with early cataract
Correct answer: An absolute scotoma approximately 15° temporal to fixation corresponding to the optic disc
The physiologic blind spot is an absolute scotoma located approximately 15° temporal to fixation where the optic disc has no photoreceptors.
Question 3: A patient shows a superior altitudinal visual field defect. The most likely cause is:
- Temporal lobe lesion
- Inferior branch retinal artery occlusion or inferior optic nerve damage (Correct answer)
- Chiasmal compression
- Cortical blindness
Correct answer: Inferior branch retinal artery occlusion or inferior optic nerve damage
Superior altitudinal defects (loss of the upper field) result from damage to inferior retinal structures or the inferior optic nerve, often from inferior BRAO or inferior AION.
Question 4: During automated perimetry, fixation losses are detected by periodically presenting stimuli at the:
- Central fixation point
- Blind spot location (Correct answer)
- Peripheral boundary of the test area
- Last seen point from the prior test visit
Correct answer: Blind spot location
The Heijl-Krakau method projects stimuli into the patient's mapped blind spot; if the patient responds, it indicates they are not maintaining proper fixation.
Question 5: What is the clinical significance of the Pattern Standard Deviation (PSD) on a Humphrey Field Analyzer printout?
- It measures overall field depression from cataract or media opacity
- It quantifies the irregularity or focal nature of the field loss (Correct answer)
- It compares the current test to the patient's prior baseline
- It reflects the variability in the patient's response time
Correct answer: It quantifies the irregularity or focal nature of the field loss
PSD measures the variability of individual test point deviations from the age-corrected average, with elevated PSD indicating focal or localized loss characteristic of glaucoma.
Question 6: Which visual field defect pattern is most characteristic of a lesion in the parietal lobe optic radiations?
- Inferior homonymous quadrantanopia ('pie in the sky')
- Superior homonymous quadrantanopia ('pie on the floor') (Correct answer)
- Bitemporal hemianopia
- Cecocentral scotoma
Correct answer: Superior homonymous quadrantanopia ('pie on the floor')
Parietal lobe lesions damage the superior optic radiations, producing a contralateral inferior homonymous quadrantanopia (superior fibers run through the parietal lobe).
Question 7: A confrontation visual field test is considered:
- The gold standard for glaucoma monitoring
- A gross screening test that detects large field defects but misses subtle losses (Correct answer)
- Equivalent to automated perimetry for detecting early disease
- The preferred method for mapping scotomas in neurological conditions
Correct answer: A gross screening test that detects large field defects but misses subtle losses
Confrontation testing is a quick clinical screening tool that reliably detects large hemianopias or quadrantanopias but lacks the sensitivity to identify early or subtle field defects.
COT Visual Field Testing 4
The 10-2 visual field test pattern is specifically designed to test points within what degree of fixation?