Vision Screening Online Training Program - How is 20/20 associated with vision and what does it mean?

Vision Screening Online Training Program

Module 6 (continued): How is 20/20 associated with vision and what does it mean?

Q.  What is visual acuity?

A.  Visual acuity is the sharpness or clarity of a person’s vision.

Q.  What does having 10/10 (20/20) vision mean and how do they get that number?

A.  Visual acuity is written as a fraction:

Numerator - the number of feet at which screening is done (e.g., 10 feet, 20 feet), example: 10/-- (20/--)

Denominator - the smallest line on which the required number of optotypes (standardized letters or symbols for testing visual acuity) are correctly identified, example: 10/20 (20/40).

It is recommended that all children be screened for visual acuity at a 10 foot distance. Documentation of distance visual acuity screening results should be recorded as the actual distance the child was from visual acuity chart. For example if the child was screened at 10 feet from the chart, 10 would be numerator used when recording results.

Q.  What do the visual acuity results mean?

A.  If one's vision is 10/35 it means:

  • At 10 feet away, the smallest line that person can see is the 10/35 line
  • A person with 10/10 vision could read that same line at 35 feet away

B.  If one's vision is 10/10 it means:

  • At 10 feet away, the smallest line that person can see is the 10/10 line



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