Visual Acuity Testing Flashcards

If a patient can only detect hand motion (HM) but not count fingers, how should VA be recorded?

Answer: HM

Hand motion (HM) is recorded when the patient can detect a hand waving but cannot count individual fingers, indicating severely reduced vision.

For a patient with nystagmus, the paraoptometric should:

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.

What does the term 'optotype' refer to in visual acuity testing?

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.

When a patient can count fingers at only 2 feet, the approximate Snellen equivalent is:

Answer: 20/2000

Counting fingers at 2 feet is approximately equivalent to 20/2000 Snellen acuity, reflecting severely reduced vision.

Which factor can artificially REDUCE measured visual acuity during testing?

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.

The Allen picture chart is specifically designed for use with:

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.

After testing VA with the patient's current glasses, the paraoptometric notes significant improvement with the pinhole. This most likely indicates:

Answer: The current glasses prescription is outdated or incorrect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.