Whenever most people hear 2020, they think of eye exams and they know 20/20 means good or “perfect” eyesight (but it’s really not that simple). Now, with the year 2020 here, every eye doctor, and anyone whose work involves the eyes, will be playing with those numbers one way or another!
But, do you really know what 20/20 means? Let’s find out!!
1) In the early part of the 20th century 20 scientists got together and measured how small an item they could each see. The average size of the smallest item became the size referred to as 20/20
2) The term developed overseas as a measurement with the metric system. 20/20 is the size of an object 20 cm high as it is seen from 20 meters away.
3) 20/20 means you can see clearly at 20 feet what should normally be seen at that distance. If you have 20/100 vision, it means that you must be as close as 20 feet to see what a person with normal vision can see at 100 feet.
4) The numbers 20/20 have to do with distance and trigonometry (angular measurement). The first 20 is the distance at which the test is performed in feet. The second is the distance at which the height of the test object occupies an angle of 1/12 of a degree.
5) At the time when eye exams were becoming more standardized and commonplace, about 100 years ago, a popular figure of speech to indicate something “just right” was 20/20. When someone could read the smallest lines on the chart, the doctor would say “Your eyes are 20/20!”