A visual acuity test assesses how well you can see at a standardized distance. Eye doctors have determined what “normal” vision is when reading at this distance and compare this with your vision.
To conduct the test, your doctor uses an eye chart positioned 20 feet away that displays rows of letters in increasingly smaller sizes. Your doctor asks you to read as many of the lines as you can without squinting, sometimes while covering one eye. If you can see all the letters clearly, you are considered to have 20/20 vision.
The doctor may also ask you to read a few lines from a preprinted card or sheet of newspaper. This simple test gives the specialist information about how well you can see close up and helps to confirm a diagnosis of refractive error.