What is 20/20 Vision?
Most of us have heard the term “20/20 vision” being used in reference to healthy, normal eyesight. Perhaps you have been told you have 20/20 vision, 20/40 vision, or even 20/15 vision. As a measurement of visual acuity, 20/20 vision is considered “good” vision. Most people, however, are unaware or have forgotten exactly what these numbers mean. Let us take a quick look at the meaning behind these figures.
Anyone who has undergone a physical examination at a doctor’s office or a comprehensive eye exam at an eye clinic has seen what is called a “Snellen chart.” This is the chart hanging on the doctor’s wall with the large “E” printed at the top. This chart has been used since the late 1800’s to measure an individual’s visual acuity. Many modern eye clinics and family physicians use an electronic “viewfinder” version of the Snellen chart, but the ratios and results are the same.
