20/20 vision may not mean that you have perfect eyesight. To have effective and comfortable vision, you must have other vision skills, and there are many people with 20/20 vision who require correction for other vision problems.
20/20 vision means that a person sitting 20 feet from an examination chart can see the size letter that someone with “normal” vision can see at that distance. Some people have better than normal vision, and this is indicated by a smaller bottom number, such as 20/l5.
It is important to have good vision at all the distances you use your eyes, such as in reading, not just at 20 feet and beyond. You also must be able to achieve good vision at all distances rapidly, because your eyes are constantly moving. 20/20 is not sufficient if it takes you a long time to shift your vision from the road to the road map. A few of the skills necessary for good vision are:
A glasses or contact lens correction may be needed to aid efficient and comfortable driving and/or reading vision.