CPOA Visual Acuity Testing 4 — Questions and Answers
Question 1: What is 'amblyopia' as it relates to visual acuity testing?
- Double vision caused by muscle imbalance
- Reduced VA in one eye not correctable with lenses due to abnormal visual development (Correct answer)
- Increased sensitivity to glare
- Blurred vision from corneal scarring
Correct answer: Reduced VA in one eye not correctable with lenses due to abnormal visual development
Amblyopia ('lazy eye') is reduced best-corrected VA in one eye caused by abnormal visual development in childhood, not explainable by organic disease alone.
Question 2: When using a mirror system to simulate 20 feet in a small room, the actual room distance is typically:
- 5 feet
- 10 feet (Correct answer)
- 14 feet
- 18 feet
Correct answer: 10 feet
A plane mirror placed 10 feet from the patient doubles the apparent distance to 20 feet, allowing standard VA testing in smaller rooms.
Question 3: When asking a patient to read the Snellen chart, the paraoptometric should instruct the patient to:
- Read only the top line
- Start from the bottom line and read up
- Read the smallest line they can see clearly (Correct answer)
- Read both eyes open simultaneously first
Correct answer: Read the smallest line they can see clearly
Patients should be directed to read the smallest line they can see clearly, as this identifies their actual acuity threshold.
Question 4: Which abbreviation correctly documents visual acuity tested without glasses?
- cc
- sc (Correct answer)
- OU
- ph
Correct answer: sc
The abbreviation 'sc' (sine correctione) means without correction and is used to document uncorrected visual acuity.
Question 5: A Snellen fraction of 20/15 indicates the patient:
- Has subnormal vision
- Sees better than average at distance (Correct answer)
- Needs a minus-power lens
- Is legally blind
Correct answer: Sees better than average at distance
20/15 means the patient sees at 20 feet what a normal person must be at 15 feet to see, indicating above-average distance visual acuity.
Question 6: Which step should the paraoptometric take if a patient wears bifocals during near visual acuity testing?
- Ask the patient to remove the glasses
- Ensure the patient looks through the reading (bifocal) segment (Correct answer)
- Test only distance VA
- Document as 'sc'
Correct answer: Ensure the patient looks through the reading (bifocal) segment
For near VA testing with bifocals, the patient should look through the bifocal (lower) segment to ensure the reading correction is being evaluated.
Question 7: LogMAR visual acuity charts (such as the ETDRS) are preferred in research because they:
- Use larger letters than Snellen charts
- Provide equal spacing of optotypes and consistent letter count per line (Correct answer)
- Eliminate the need for testing at 20 feet
- Can be used without any lighting requirements
Correct answer: Provide equal spacing of optotypes and consistent letter count per line
ETDRS/LogMAR charts have equal numbers of letters per line and equal spacing between lines on a logarithmic scale, allowing more precise statistical analysis.
CPOA Visual Acuity Testing 4
What is 'amblyopia' as it relates to visual acuity testing?