Question

Normal vision is called 20-20 vision. These numbers are actually a ratio—a comparison of the distance you can see to the distance a normal-sighted person can see. For example, a person with 20-30 vision can see from a distance of 20 feet what a person with 20-20 vision can see from a distance of 30 feet. Based on this knowledge, explain what the following numbers mean regarding vision.

a. 20-100
b. 20-40

Answer 1

The explanations are provided below:

Explanation:

a. A person with 20-100 vision can see from a distance of 20 feet what a person with 20-20 vision can see from a distance of 100 feet. This simply means that the person can see about 100 feet what a normal sighted person can.

b. A person with 20-40 vision can see from a distance of 20 feet what a person with 20-20 vision can see from a distance of 40 feet.

This is the same as explanation (a).The person can see from a distance of 40 feet what a normal person can see.

Answer 2

See below.

Explanation:

a. A person with 20-100 vision can see from a distance of 20 feet what a person with 20-20 vision can see from 100 feet.

b. If you have 20-40 vision you can see from 20 feet what a person with 20-20 vision can see from 40 feet.