CPOA Visual Acuity Testing 5 — Questions and Answers
Question 1: If a patient can only detect hand motion (HM) but not count fingers, how should VA be recorded?
- 20/400
- CF at 3 feet
- HM (Correct answer)
- LP
Correct answer: HM
Hand motion (HM) is recorded when the patient can detect a hand waving but cannot count individual fingers, indicating severely reduced vision.
Question 2: For a patient with nystagmus, the paraoptometric should:
- Occlude the fellow eye tightly for monocular testing
- Allow the patient to adopt their preferred head position (null point) (Correct answer)
- Use only the pinhole occluder
- Test only binocular VA
Correct answer: Allow the patient to adopt their preferred head position (null point)
Patients with nystagmus often have a null point (preferred head position) where nystagmus is minimized and VA is best; testing should allow this position.
Question 3: What does the term 'optotype' refer to in visual acuity testing?
- The type of occluder used
- The standardized symbols or letters used on acuity charts (Correct answer)
- The lighting system behind the chart
- The scale used to measure diopters
Correct answer: The standardized symbols or letters used on acuity charts
Optotypes are the standardized test symbols (letters, numbers, or shapes) on VA charts, designed to subtend a specific visual angle at a given distance.
Question 4: When a patient can count fingers at only 2 feet, the approximate Snellen equivalent is:
- 20/100
- 20/200
- 20/400
- 20/2000 (Correct answer)
Correct answer: 20/2000
Counting fingers at 2 feet is approximately equivalent to 20/2000 Snellen acuity, reflecting severely reduced vision.
Question 5: Which factor can artificially REDUCE measured visual acuity during testing?
- Bright, even chart illumination
- Patient squinting or having uncorrected refractive error (Correct answer)
- Using the pinhole occluder
- Testing at exactly 20 feet
Correct answer: Patient squinting or having uncorrected refractive error
Uncorrected refractive error or patient squinting (which acts as a partial pinhole) can cause artificially reduced or variable VA measurements.
Question 6: The Allen picture chart is specifically designed for use with:
- Adults with low literacy
- Pre-school children aged 2.5–5 years (Correct answer)
- Patients with color blindness
- Elderly patients with dementia
Correct answer: Pre-school children aged 2.5–5 years
The Allen picture chart uses familiar pictures (house, bird, phone, etc.) recognizable by young children who cannot yet identify letters.
Question 7: After testing VA with the patient's current glasses, the paraoptometric notes significant improvement with the pinhole. This most likely indicates:
- The patient has macular degeneration
- The current glasses prescription is outdated or incorrect (Correct answer)
- The patient has glaucoma
- The chart illumination was insufficient
Correct answer: The current glasses prescription is outdated or incorrect
Pinhole improvement over best-corrected VA with current glasses suggests the prescription is no longer optimal and needs updating.
CPOA Visual Acuity Testing 5
If a patient can only detect hand motion (HM) but not count fingers, how should VA be recorded?