What does "20/40 vision" indicate?

What does "20/40 vision" indicate?

• A. A person sees clearly at 20 feet what should normally be seen at 40 feet
• B. A person sees clearly at 40 feet what should normally be seen at 20 feet
• C. A person sees poorly at 20 feet compared to normal vision
• D. A person has perfect vision

Answer: (A)

The statement that "20/40 vision" indicates a person sees clearly at 20 feet what should normally be seen at 40 feet is correct. This measurement is part of the Snellen chart system used to assess visual acuity. In this context, the first number (20) refers to the distance in feet at which the test is conducted. The second number (40) indicates the distance at which a person with normal vision (20/20 vision) would be able to see the same details of an object. Thus, if a person has 20/40 vision, they are able to see at 20 feet what a person with normal vision can see at 40 feet. This means their vision is not as clear or sharp as that of someone with 20/20 vision. Understanding this measurement helps in evaluating how well a person's vision compares to standard visual acuity benchmarks.

The statement that "20/40 vision" indicates a person sees clearly at 20 feet what should normally be seen at 40 feet is correct. This measurement is part of the Snellen chart system used to assess visual acuity. In this context, the first number (20) refers to the distance in feet at which the test is conducted. The second number (40) indicates the distance at which a person with normal vision (20/20 vision) would be able to see the same details of an object.

Thus, if a person has 20/40 vision, they are able to see at 20 feet what a person with normal vision can see at 40 feet. This means their vision is not as clear or sharp as that of someone with 20/20 vision. Understanding this measurement helps in evaluating how well a person's vision compares to standard visual acuity benchmarks.