WHAT DOES '20/20 VISION' MEAN?
Dr. Jim Martin 06/01/2015
You’ve probably heard the term “20/20” vision before. Often times, 20/20 vision is a term that is used to describe perfect vision by laymen. While 20/20 vision is considered vision that is not in need of correction, it isn't exactly “perfect.” In fact, there is a lot more consideration that goes into vision testing than simply reading an eye chart.
What Is 20/20 Vision?
Generally speaking, 20/20 vision is only a visual acuity measurement. This type of vision is measured using a Snellen chart. Snellen charts show letters in a series getting progressively smaller with each line. This is the eye chart that most everyone can recognize. A giant "E" starts the series of letters and each line gets smaller. The smaller lines denote the level of vision a person has.
20/20 vision is considered to be average vision. This means that a person with 20/20 vision sees at 20 feet what other people with normal vision see at 20 feet. Often thought of as “perfect” vision, it is the benchmark for optometrists when it comes to vision acuity, but it is not really perfect. This generally means that a person will not need corrective lenses for distance. That does not, however, mean that a person with 20/20 vision won't have other eye problems that may require treatment. There are several different measurements that are used to determine if a person is in need of vision treatment.
There are people who have vision that is better than 20/20. 20/15 vision is not uncommon. In these individuals, they can see at 20 feet what normal people can see at 15 feet.
While vision acuity is a good benchmark for eyesight, it isn't the only measurement that needs to be taken. Vision acuity tests are not perfect. In many cases, people can generally “guess” what letter comes next, even if the letters are somewhat blurry. This lends itself to misleading results, in some cases.
Additional testing is generally carried out to get a full and clear picture of an individual's eyesight. For example, peripheral vision tests, and eye coordination tests are often carried out in conjunction with Snellen chart tests to get a fuller picture of an individual's eyesight.
If you have questions or concerns about your vision, don't hesitate to call the professionals at Broome Optical in Amarillo. We'll be happy to answer your questions and help ensure your eye health.