What Does 20/20 Vision Mean — and Can You See Better Than 20/20?

20/20 vision means that, standing 20 feet from an eye chart, you can read what a person with typical vision can read from 20 feet. It's considered normal sharpness of vision, not perfect vision, and plenty of people see better than 20/20.

Patients ask me about these numbers all the time, usually right after reading the chart. Here's what they mean, in plain words.

What do the two numbers mean?

The first number is how far you are from the chart, which is 20 feet in the US standard. The second number is the distance at which a person with typical vision could read the same line.

• 20/20: You read at 20 feet what a typical person reads at 20 feet.
• 20/40: You need to be at 20 feet to read what a typical person can read from 40 feet away. Your vision is less sharp.
• 20/15 or 20/10: From 20 feet, you can read a line that a typical person can only read from 15 or 10 feet. Your vision is sharper than average.

A bigger second number means blurrier vision. A smaller second number means sharper vision.

Most exam rooms don't have 20 feet of space, so we use mirrors or digital charts sized to give the same result.

Can you see better than 20/20?

Yes. Many healthy young adults see 20/15 with their glasses or contacts, and some see 20/10. It depends on how well light focuses in your eye, the health of the retina (the light-sensing layer at the back of the eye), and how tightly packed the light-sensing cells are in the center of your vision.

When we fine-tune a prescription, the "one or two?" part of the exam, we aim for the sharpest vision you can comfortably get. That's often better than 20/20, not just 20/20.

What are 20/40 and 20/200?

Two other numbers come up often:

• 20/40 is a common cutoff for driving without restrictions in many states. If you're near that line, it's time for an exam and probably new glasses.
• 20/200 in the better eye, even with glasses or contacts, is the US definition of legal blindness. Many people with 20/200 vision without glasses see 20/20 once they put them on. That's just a strong prescription, not legal blindness.

Does 20/20 mean my eyes are healthy?

No. This is the most important part of this post. The eye chart measures one thing: how sharply you see small, high-contrast letters straight ahead. It doesn't measure:

• Eye health: Glaucoma, early macular degeneration and diabetic eye disease often cause no blur at first. People can read 20/20 while their optic nerve is being damaged. You can read more in our glaucoma post.
• Side (peripheral) vision, which glaucoma takes away first
• Contrast: how well you see in fog, at dusk or with gray-on-gray
• How well your eyes work together, including focusing up close, eye teaming and depth perception
• Color vision
• Comfort: eye strain, headaches, dry eye

That's why a school or DMV screening that says "20/20, pass" isn't the same as an eye exam. A screening checks the chart. An exam checks the eye.

Why can my child read 20/20 and still struggle?

Children can often squeeze their focusing muscles hard enough to read the distance chart, even when they're farsighted or their eyes don't team well up close. They pass the screening, then get headaches, lose their place or avoid reading. A full exam checks focusing and eye teaming at reading distance, not just the chart on the wall. Our pediatric eye care page covers what we look for.

When should you see an eye doctor?

Book an exam if:

• signs or the TV look less clear than they used to, or you're squinting
• your vision is worse at night or you see glare and halos around lights
• you get headaches or tired eyes after reading or screen time
• your child fails a school screening, or passes but struggles with reading
• it's been more than a year since your last exam, or you have diabetes, glaucoma in the family or a strong prescription

Call us right away or go to the emergency room if your vision drops suddenly, you see a curtain or shadow, or you notice new flashes and floaters.

How we do it at Bolt Eye Group

At Bolt Eye Group, reading the chart is the start of the exam, not the end. We refine your prescription carefully, then look at the health of the whole eye. Every patient gets retinal photos and a corneal map for $39. With an in-office telehealth visit, that same $39 also covers two OCT scans, one of the optic nerve and one of the macula. OCT is a detailed cross-section of the retina and optic nerve that can show changes long before they affect the chart. Our post on how often you should get an eye exam explains why once a year matters even when you see well.

Our opticians make sure your new lenses match the prescription and are set to your eyes in the frame you choose, so you actually get the sharpness we measured in the exam room.

We see patients at five offices: Canton, East Cobb/Marietta, Lawrenceville, Riverdale and Johnson City, TN. We accept VSP, EyeMed, Davis Vision, Spectera, Medicare and major medical plans, including Blue Cross Blue Shield, Aetna, UnitedHealthcare, Cigna and Humana.

Frequently asked questions

Is 20/20 perfect vision?

No. It's normal, healthy sharpness, but many people see better, such as 20/15. And 20/20 says nothing about eye health, side vision or how well your eyes work together.

Is 20/40 vision bad?

It's not bad, but it's less sharp than average, and it's near the line many states use for driving without glasses. Most people at 20/40 see noticeably better with a prescription.

What's the best vision a person can have?

Some people with very healthy eyes can see 20/10 or even a little better. For most people, 20/15 to 20/20 with the right glasses or contacts is excellent.

If I see 20/20, do I still need an eye exam?

Yes. Glaucoma, diabetic eye disease and early macular degeneration often don't affect the eye chart until damage has already happened. A yearly exam with retinal imaging catches them early.

Can 20/20 vision change?

Yes. Prescriptions change, especially in childhood, the teen years and after 40, when near vision starts to fade. Our post on blurry vision up close after 40 explains that change.

Book an exam at your nearest Bolt Eye Group office

Whether you're 20/20 or not sure anymore, book an exam at Bolt Eye Group in Canton, East Cobb/Marietta, Lawrenceville, Riverdale or Johnson City, TN. Find your office and book online.