A 20/20 vision refers to normal vision where an average person is able to read a certain row of letters on an eye chart while standing 20 feet away. An eye chart measures visual acuity (sharpness of vision). The top number is a measurement of the individual’s distance from the chart in feet, while the bottom number means the distance at which a person with normal eyesight can read the same line. With a 20/20 vision, a person can perform most or even all the basic tasks in daily life.