20/20 is an English measurement for detail resolution. The top number represents the testing distance, which is usually 20 feet. Testing vision at any closer distance will cause the distance glasses prescription to have too much convex lens power and will make the distance vision blurry. The bottom number is an old English measurement called foot-letter. So a 20 foot-letter size means that the letter that you see is 1 second of arc high at 20 feet.60 seconds of arc equals 1 degree of arc.
Some people can genetically see better than 20/20. For example 20/15. Typically athletes like professional baseball players that excel at hitting have this genetic ability. At Optiexpress, we take pride in making sure that your vision will be as clear as possible, even if you don’t care about your batting average!