Many people do not know the meaning behind 20 20 vision.
20 20 Eyesight refers to how well someone can see clearly up to 20ft. In countries that use the metric system, 20/20 is actually referred to as 6/6.
When your doctor tells you have 20-20 vision, this does not really mean you have prefect eyesight. Being able to see up to these distances is, of course, very useful. However, there are other things to consider when you want to take your Eye Care Health into consideration.
You might be interested in taking a Vision Test to see how well you perform. Figuring how well your peripheral awareness is or eye coordination, depth perception, side vision, focuses, and even color vision is all equally important in determining how healthy your eyes are. In fact, color vision is very important in figuring out your visual ability.
To test your visual acuity (your ability to see items and wording at a distance), you will use a Snellen Chart.
Almost everyone knows what this eye chart looks like, but many might not have known the name of it. This particular chart has rows of letters that become smaller and smaller as they go down into subsequent rows. The person reads them out loud, usually while covering one eye, and the doctor can tell how good his or her eyes are by the lines that he starts to have trouble reading on.
A person with 20 20 vision is able to see the same thing that a normal person would be able to see from 20 feet away. If the person's eyes are worse than a normal person, he may have 20 40 vision instead. In this case he would need to stand at 20 feet to see what a normal person would be able to see from 40 feet away.
Basically the second “20” in 20 20 doesn't refer to you, but refers to a “normal person.” If the patient has 20 100 vision, then he or she would have to stand 20 feet away from something to see it, while a normal person could see the same thing from as far back as 100 feet.
Going in the opposite direction, an individual with 20 10 vision would have much better eyesight than a normal person. They would be able to see something at 20 feet while a normal person would need to stand 10 feet away from the object to see it. Of course, usually refers to “read,” because even if you can't read something you would technically still be able to see it.
Think of it like this – there's a sign 20 feet away from you. You are able to read the sign perfectly, but your friend needs to step 10 feet closer to read it.
Assuming your friend has 20 20 vision, you would have 20 10 vision.
If you want to protect your eyesight, you should go see an eye care professional or eye care specialist at least once a year to get your vision checked out.