What Does 20/20 Vision Mean? 20/40, 20/200 and Your Eye Chart Results Explained

The short answer: 20/20 vision means that, standing 20 feet from an eye chart, you can read the letters a person with normal eyesight can read at that same distance. It is the standard for normal distance sharpness, not a score for perfect eyes. A bigger second number means blurrier vision: with 20/40 vision you need to be at 20 feet to read what normal eyes can read from 40 feet away. A smaller second number, like 20/15, means sharper than average.

Below, we explain how the numbers work, what common results such as 20/25, 20/30, 20/40, 20/100 and 20/200 mean in everyday life, what Georgia requires for a driver's license, what legally blind means, and why a 20/20 result is only one small part of a full eye exam.

How the 20/20 fraction works

Your vision score is written as a fraction, but it is not a percentage and you should not divide it. The two numbers mean:

• The top number is the testing distance, which is 20 feet in the United States. (Most exam rooms use mirrors or a calibrated screen so the letters act as if they were 20 feet away.)
• The bottom number is the distance at which a person with normal vision could read the smallest line you read correctly.

So 20/60 means the smallest letters you can make out from 20 feet are letters a person with normal vision could read from 60 feet. Countries that use meters write the same idea as 6/6 (equal to 20/20) or 6/12 (equal to 20/40).

The classic chart with the big E at the top is called a Snellen chart, named after the Dutch eye doctor Herman Snellen, who designed it in the 1860s. Today many offices show the letters on a digital screen that can switch between letters, numbers and pictures for young children.

What common vision scores mean

Here is a plain-language guide to the results people ask us about most. Each eye is measured separately, and we record both your vision without correction and your vision with your glasses or contacts.

• 20/10 to 20/15: sharper than normal. You can read at 20 feet what most people must move closer to see.
• 20/20: normal distance sharpness.
• 20/25: very slight blur. Many people do not notice it, though a small prescription can make night driving and screens crisper.
• 20/30: mild blur. Signs and faces across a room are a little soft; some people choose glasses for driving, movies or class.
• 20/40: mild to moderate blur. Most people notice it on the road, especially at night.
• 20/50 to 20/70: moderate blur. Reading signs, the board at school or the TV across the room becomes hard without correction.
• 20/100: you have to be at 20 feet to see what normal eyes see from 100 feet. Day-to-day tasks are difficult without glasses or contacts.
• 20/200: the big E at the top of the chart is often the only letter you can read. If glasses or contacts bring you back to normal, this is simply a strong prescription, not blindness.

The key point: your uncorrected score tells us how much your eyes need help, and your corrected score tells us how well they can see with that help. A score that cannot be corrected to near 20/20 is the one that gets our attention, because it can point to an eye health problem rather than just a prescription.

Is 20/20 perfect vision? Not quite

The American Optometric Association is clear that 20/20 only describes the sharpness of your vision at a distance. A good day-to-day vision system also needs:

• Side (peripheral) vision, which glaucoma quietly narrows long before the center is affected;
• Focusing up close, which changes in your 40s; see our post on blurry vision up close after 40;
• Eye teaming and depth perception, which matter for reading, sports and driving;
• Color vision and contrast, which affect night driving and seeing in dim light; our post on night driving glare and halos covers why a 20/20 score in a bright exam room can still feel worse on a dark road;
• Healthy eyes, which no eye chart can confirm.

Someone can read the 20/20 line and still have astigmatism that causes headaches, a lazy eye that blurs one side, early cataract glare or keratoconus changes that only show up on a corneal map.

Why your vision is not 20/20

When the chart result is worse than 20/20, the reason is usually one of these:

• Nearsightedness (myopia): far things are blurry, near things are clear. It often starts in childhood and tends to worsen through the school years; our myopia control page explains how we work to slow it in kids.
• Farsightedness (hyperopia): the eye works harder to focus, especially up close, which can cause tired eyes and headaches.
• Astigmatism: an unevenly curved cornea or lens makes things blurry or stretched at all distances; see astigmatism without surgery.
• Presbyopia: the normal, age-related loss of near focus.
• Eye conditions: cataracts, keratoconus, macular degeneration, diabetic eye disease, dry eye and others can lower vision in ways a new prescription alone cannot fix.

20/20 vision in children

A child who passes a school screening has usually read a distance chart well enough on that day. That is helpful, but it does not check focusing up close, eye teaming, or eye health, and children rarely complain because they assume everyone sees the way they do. Our article on school vision screening vs. a full eye exam explains the gap. One eye seeing 20/20 while the other sees 20/60, for example, can hide a lazy eye that is easiest to treat while a child is young; read more in lazy eye (amblyopia) in kids or on our kids' eye exams page.

Driving in Georgia: what vision do you need?

According to the Georgia Department of Driver Services, a regular (non-commercial) driver's license requires at least 20/60 in one eye, with or without glasses or contacts, plus a horizontal field of vision of at least 140 degrees. Commercial drivers have a stricter federal standard of at least 20/40 in each eye. If you do not pass the vision screening at a DDS center, you will be given a vision report form for an optometrist or ophthalmologist to complete.

If you need glasses to pass, your license will carry a corrective lens restriction, so keep your glasses current and in the car. Meeting the legal minimum is not the same as seeing your best, though. Clearer vision gives you more time to react, which is why we often recommend a driving prescription even for mild blur.

What does legally blind mean?

In the United States, the Social Security Administration defines legal (statutory) blindness as vision in the better eye that cannot be corrected to better than 20/200, or a field of vision in the better eye of 20 degrees or less. The key words are better eye and with correction. Many people who read only the big E without their glasses see 20/20 with them, so they are not legally blind; they simply have a strong prescription.

Vision that stays reduced even with the best glasses, contacts, medicine or surgery is called low vision. The National Eye Institute describes it as vision loss that makes everyday tasks such as reading, driving or recognizing faces hard. Low vision aids and vision rehabilitation can help people make the most of the sight they have.

What we measure at your eye exam (beyond the chart)

At Reimbold Eye Group, reading the chart is only the start. We use a digital phoropter to fine-tune your prescription without the old stress of choosing between 1 and 2, and every exam includes retinal photos and corneal topography, a map of the front of the eye that helps us catch keratoconus early. Depending on your needs, we also check color vision, depth perception, eye pressure, side vision and eye teaming. Our eye exam technology page shows the instruments we use, and our eye exams in Alpharetta page walks through a typical visit.

If you wear contact lenses, a contact lens exam and fitting checks how your lenses sit on the eye as well as how clearly you see with them. Wondering whether your plan covers the visit? See the insurance we accept; we accept all vision plans and most major medical plans (not Medicaid).

Getting back to sharp, comfortable vision

For most people, the fix for a less-than-20/20 result is simple: an updated prescription in glasses or contact lenses. Thin, high-index lenses help when the prescription is strong (see glasses for a strong prescription), and our face shape glasses guide helps you pick frames you will want to wear. Some adults also ask about laser vision correction; our post on LASIK: what to know covers who is a good candidate. When an eye condition is the reason vision will not correct to normal, we explain what we found, treat what we can in our office and coordinate with a specialist when needed.

Frequently asked questions

Is 20/20 vision perfect vision?

No. 20/20 means your distance vision is as sharp as the standard used for normal vision. It says nothing about side vision, depth perception, focusing up close, color vision, how well your eyes team together or whether your eyes are healthy. Many people with 20/20 vision still need reading glasses, have eye strain or have an eye disease that only an exam can find.

Is 20/40 vision bad?

20/40 is mild blur. It means you have to be at 20 feet to read what a person with normal vision can read from 40 feet. Many people at 20/40 notice fuzzy road signs, especially at night, and feel more comfortable with glasses for driving. In Georgia, a regular driver's license requires at least 20/60 in one eye, with or without glasses, so 20/40 usually passes, but clearer vision is safer.

Can you have better than 20/20 vision?

Yes. 20/15 means you can read at 20 feet what a typical person needs to be at 15 feet to read, so your distance vision is sharper than average. Some people, often younger patients, reach 20/15 or even 20/10 with or without glasses.

What vision is considered legally blind?

In the United States, legal blindness means your better eye cannot be corrected to better than 20/200 with glasses or contacts, or your field of vision in the better eye is 20 degrees or less. Someone who sees 20/200 without glasses but 20/20 with them is not legally blind.

Does 20/20 vision mean I do not need an eye exam?

No. An eye chart only measures sharpness at a distance. Glaucoma, diabetic eye changes, early macular degeneration and keratoconus often cause no blur in the early stages. A comprehensive eye exam checks eye health as well as vision, which is why adults and children with 20/20 vision still need regular exams.

Eye exams in Alpharetta

Whether your last chart said 20/20 or you are squinting at road signs, a comprehensive exam tells you how well you see and how healthy your eyes are. Book online or call 770-776-9000. Reimbold Eye Group is at 4180 Old Milton Pkwy 1-D, Alpharetta, GA 30005. Not sure when you are due? Here is how often you should get an eye exam.

This article is for general education and is not a diagnosis. If you notice a sudden change in your vision, call us or see a doctor the same day.