20/20 Vision

20/20 vision is when you are able to distance in feet from the readability of a pair of objects. Since it is called 20/20 vision, it is referring to how good your vision is at 20 feet away. The chart that they use to test your vision is called the Snellen chart, which is an eye chart that is used by eye care professionals.

When eye care professionals refer to your vision, they particularly use symbols that seem much like fractions. So, when they say 20/40, it is like you have half of the vision that you should have. When they say 20/200, your eye vision is so bad that you are considered blind. When they refer to 20/20 vision, it means that you have nearly the best type of vision for a human. Although, 20/20 vision is not the best of the best when it comes to your vision; it is the next closest thing. An example of vision that is much better than 20/20 is 20/10, which is usually only found in animals. The animal that is most commonly found with 20/10 is the hawk. However, there is even a vision that is better than 20/10, but it is not found in humans at all. This vision is called 20/2, which is 10 times better than the average human eyesight. An animal can only possess this.

When eye doctors refer to 20/20 vision, they are talking about an eyesight that is mostly considered "normal." 20/20 vision is so common in the U.S. that a show is even named after it.