Vision & Cataracts
So…What Is 20/20 Vision?
October 3, 2012
You May Be Surprised…
With all of the complicated terms associated with vision, from glaucoma pressures to surgical terms, one might think that “20/20 Vision” would have a far more complicated meaning than it does. In fact, you may be surprised just how simple the basis for 20/20 vision is.
When our patients take a basic “eye chart” vision test, they are undergoing what is referred to as a visual acuity test. Sound familiar?
This test utilizes a white chart, also known as a “Snellen Chart,” with progressively smaller lines of letters moving down the chart. From twenty feet away, with one eye covered, our patients read aloud the line with the smallest text they can see clearly. This is repeated with the other eye covered.
So What Is Normal Vision?
While 20/20 vision refers to “normal” quality eyesight, what 20/20 actually means is this: At 20 feet from the chart, a person with “normal” vision can read the smallest line of text with one eye closed. Therefore, that person can see at 20 feet away what a person with “normal” vision can also see clearly from 20 feet away. Someone with 20/40 vision must be no more than 20 feet away to clearly see what a person with 20/20 vision can see from 40 feet. This measurement scale continues upward in 20-foot increments to such distances as 20/200, which is considered legally blind.
Attaining 20/20 vision
Some people find that glasses and contact lenses are too uncomfortable and inconvenient, or they simply do not want to be dependent on these things. Others find that corrective lenses are not enough and can benefit from a combination of LASIK surgery and corrective lenses. If you do not have 20/20 vision, or if you have 20/20 vision but still experience vision problems, Dr. Davies can help you decide if corrective lenses or LASIK surgery would be the best option for you.
Whatever your visual acuity, hopefully, this information helps clear up any confusion you may have about the term “20/20 vision.” If you have questions that have not been answered here, please email them directly to DrDavies@DaviesEye.com← BACK TO OUR BLOG