There’s no better time to focus on 20/20 vision, preserving your eye health and acknowledging the significance of regular eye exams than during the year 2020.
“2020 is an iconic number for all eye folks,” said Burt Dubow, OD, FAA. “Even though it is not the very best visual acuity, it is the standard most people use when referring to good vision,” adds the All About Vision editorial advisory board member.
In the spirit of 2020, let’s bring clarity to some commonly-asked questions regarding 20/20 vision.
What is 20/20 vision?
According to the American Optometric Association, 20/20 vision describes how clear or sharp someone’s vision is — also referred to as visual acuity.
When measuring visual acuity, the first number describes how far away you stand from the eye chart, so the first 20 means you’re standing 20 feet away. The second number is the distance from which someone with normal eyesight is able to read the same line on the chart.
To put it into perspective, if you have 20/100 vision, you have to be as close as 20 feet to clearly see what a person with normal vision can see from 100 feet away. So, if your vision is 20/20, you’re able to clearly see from the expected distance, which is why it’s considered normal vision.
In most cases, the first number when measuring visual acuity is 20, but the second number can change depending on your eyesight.
What is perfect vision? Is it 20/20?
20/20 is considered normal vision and is commonly used as a point of reference when measuring visual acuity, but it is not perfect.
Contrast sensitivity, peripheral vision and depth perception also affect the quality of your eyesight and should be taken into consideration when determining the strength of your vision.
How is 20/20 vision determined?
Eye doctors normally test vision by having patients read what’s known as the Snellen chart. The chart consists of eleven rows of capital letters, starting with one large letter at the top.
Row by row, the number of letters increases while the size of the letters decreases. An eye doctor tests each eye’s vision by asking you to read the letters on the chart aloud, without wearing eyeglasses or contact lenses.
Is 20/20 vision common?
According to the University of Iowa Hospitals & Clinics, approximately 35% of adults have 20/20 vision without glasses, contacts or other means of correction. When corrective measures are applied, the number of adults with a visual acuity of 20/20 shoots up to around 75%, while the remaining 25% of adults still don’t see very well.
What is 20/15 vision? What is 20/40 vision?
Applying the information of how 20/20 vision is determined, someone with 20/15 vision can clearly read at 20 feet away what others could read at 15 feet away, making 20/15 vision better than 20/20.
Having 20/40 vision means that someone can read clearly from 20 feet what someone else could read from 40 feet away, making it worse than 20/20 vision.
How can vision be corrected to 20/20?
“If someone’s vision is as bad as, say, 20/40, eye care professionals characteristically aim to improve it to at least 20/20 through prescription glasses, contact lenses or corrective surgery,” says James Chapman, assistant dean of clinical affairs at the University of the Incarnate Word Rosenberg School of Optometry in San Antonio, Texas.
“At 20/30, though, a patient may or may not want vision correction, depending on their work or lifestyle,” he continues. “For instance, an accountant might value sharper up-close vision more than a farmer. Therefore, the accountant might ask for vision correction to at least 20/20.”
Can you have different visual acuity in each eye?
It’s possible for the visual acuity to differ between a person’s eyes, but it’s usually not by much.
“Ninety-nine percent of the time, the two eyes are identical and symmetrical, which means that they’re basically mirror images of each other,” Chapman says.
In rare cases where someone has drastic visual acuity differences, like 20/20 and 20/100, that person may still see as well as their stronger eye (20/20), but their depth perception may be unbalanced, making vision correction necessary.
Will you need glasses or contacts with 20/20 vision?
More often than not, someone with 20/20 vision won’t need any kind of vision correction because they have enough visual clarity to accomplish daily tasks and activities without issues. However, if someone is required to stare at a computer screen for a long period of time and experience headaches because of it, they may need to look into an option like blue-light blocking glasses, even if their vision is 20/20.