About one-third of Americans have 20/20 vision. The numbers themselves come from a system of measurement eye doctors use to evaluate how your vision compares to the average person's. They determine this by having you stand 20 feet away from an eye chart and reading aloud the letters that appear on different lines of the chart.
If you stand 20 feet from an eye chart and read the line of letters that people with average vision can see clearly from that same distance, you have 20/20 vision. The numbers simply mean that from 20 feet away, what you can see clearly is the same as what the average person can see clearly.
When someone can't see things as sharply as someone with 20/20 vision, they may learn that they have 20/40 vision or 20/100 vision. Those numbers mean that the smallest letters they can clearly decipher from 20 feet away are the same as what an average person can clearly decipher from 40 or 100 feet away. People with 20/40 or 20/100 vision can't see things in the distance as sharply as people with 20/20 vision can.
You may be disappointed to hear that having 20/20 vision doesn't give you the license to brag about having stellar eyesight. It just means that you can see as well as the average person who doesn't need to wear glasses or contact lenses.
Some people actually have better-than-20/20 vision. People with 20/15 vision can see things clearly from 20 feet away that the average person can't see clearly unless they stand 15 feet away. Similarly, an even smaller percentage of people have 20/10 vision and can see what the average person would have to stand 10 feet away to see.
However, some people with 20/20 vision (or even 20/10 vision) may still need to wear glasses or contact lenses. That's because a 20/20 measurement needs to take into account things like if you can discern colors properly or how well your peripheral vision and depth perception work. An eye chart test also can't measure how well you can see close-up items or if the shape of your eye affects your ability to see clearly.
Some people have 20/20 vision because they can see well at a distance, but when they look at things close-up, those things appear blurry. These people are farsighted and may need to wear glasses to read, sew or do other close-up activities.
After the age of 40, many people can't focus well on close-up items that they used to be able to see clearly. They may need to wear reading glasses due to age-related vision changes despite otherwise having 20/20 vision.
Finally, there are people with 20/20 vision who have astigmatism, or blurry vision as a result of an irregular eye shape. These people may also need to wear glasses or contact lenses to improve blurry vision.
If you don't have 20/20 vision, wearing glasses or contact lenses will help you get there. About 75 percent of people who wear corrective lenses can achieve a 20/20 result by retaking the vision test with their glasses on or their contact lenses in.
Some people may not reach 20/20 vision while wearing corrective lenses, but glasses or contacts can still help enhance their vision. Even if corrective lenses don't get your vision to 20/20, it's important to know how well you score. To safely operate a motor vehicle, you are required to score 20/40 or better on an eye chart test while wearing glasses or contacts. If you get lower than that, you may not be able to get a driver's license. If you score 20/200 with corrective lenses, you're considered legally blind.
20/20 vision doesn't translate to "perfect" vision by any means, but it does denote strong visual acuity at a distance. A check-up with your eye doctor can help you determine if you have 20/20 vision and, if not, whether corrective lenses can help you reach it.
Schedule a visit with The EyeDoctors to determine if you need corrective lenses.