NHA Certified Clinical Medical Assistant (CCMA)Clinical Patient CareEasy
A medical assistant is performing a physical examination on a patient. When measuring the patient's visual acuity using a Snellen eye chart, what is the recommended distance the patient should stand from the chart?
- A15 feet
- B10 feet
- C25 feet
- D20 feet
Show answer & explanationAnswer & explanation
Correct answer: D. 20 feet
The Snellen eye chart is standardized for use at a distance of 20 feet (or 6 meters). This distance allows for consistent and accurate assessment of visual acuity, as the results are expressed as a fraction (e.g., 20/20, 20/40), where the numerator is the testing distance.
Why the other options are wrong
- A. 15 feet is not the standard distance for Snellen chart testing.
- B. 10 feet is too close for standard Snellen chart testing, which would artificially improve the patient's perceived acuity.
- C. 25 feet is too far for standard Snellen chart testing, which would artificially worsen the patient's perceived acuity.
Snellen Chart Distance
The Snellen eye chart is used to measure visual acuity by having the patient read lines of letters from a specific distance. The standard testing distance is 20 feet (6 meters).
- Measures visual acuity.
- Standard distance is 20 feet.
- Results expressed as a fraction (e.g., 20/20).
Memory trick: Twenty feet, clear sight, that's the Snellen's right.