Have you ever had an eye exam? If so, your doctor has probably asked you to cover one eye and read letters from a special eye chart.

Eye charts usually contain several rows of letters. The top row begins with very large letters. The letters get smaller and smaller the closer the rows are to the bottom of the chart.

What does identifying your ABCs have to do with eyeglasses? Each line of the chart has been assigned a number. During the test, patients read each line of the chart until the letters become too small to read easily.

If you can read the line labeled 20 from a distance of 20 feet, this means you have 20/20 vision.

20/20 is considered normal vision. If you can only see the giant letter at the top of the chart labeled 20/200, you have 20/200 vision.

A score of 20/200 means you would need to stand much, much closer (20 feet) to read something most people can read from 200 feet away. People with vision scores of 20/200 or worse are considered legally blind.

There are many different medical reasons people wear glasses, but the simple answer is that glasses help people see better. Some people wear glasses for reading things that are far away or for driving.

Other people only wear glasses when they’re doing an up-close activity, like reading, writing or knitting. Some people wear glasses all the time.

People who have difficulty seeing objects that are far away are called “myopic” or “nearsighted.” This means they can easily see objects that are close to them, but when viewing objects in the distance, the image can appear fuzzy.

People who have difficulty reading and seeing things close-up are called “hyperopic” or “far-sighted.” Another condition that can cause people to need glasses is “astigmatism,” which occurs when part of the eye is irregularly shaped.

Thankfully, myopia, hyperopia and astigmatism can usually be corrected by wearing eyeglasses or contact lenses. Both eyeglasses and contact lenses use convex or concave lenses to bend the light entering the eye. This refocuses the eye, helping to correct vision problems.


20 Join the Discussion

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    • Hi, Emma! We think it is awesome that you are getting glasses! We bet you will look WONDERful in them, and we hope they help you to see better! There are LOTS of great Wonder Friends here in Wonderopolis who wear glasses, too! :-)

        • Hi jojaa! Since our Wonders are sometimes updated, the proper way to cite the publishing date is to list the date you consulted our page for your research. Thanks for WONDERing with us! :)

    • Many of our AWESOME Wonder Friends wear glasses, Julie! Thanks for sharing about your friends, Kate and Alexa! We’re super glad you visited Wonderopolis today and left us this GREAT comment…THANK YOU! :-)

  1. I have glasses. Some people say that having glasses is a big joke. That you only get them if you are a nerd. I have 20/200 vision. I mean it’s just an object meant for helping you see, and it is NO funny madder. It is RUDE to make fun of people with glasses and SOMEONE needs to be heard. :(

    • Glasses are a great thing, especially when they help your vision, Quincy! Don’t let anyone make you feel silly– those glasses are like a new set of eyes for many people! We’re so glad you’re WONDERing with us today! :)

    • Great Question, Chris! Some people wear glasses for fashionable reasons. As long as it doesn’t hurt their eyes, we think that’s okay. Thanks for WONDERing with us today, Wonder Friend! :-)

  2. My classmates laugh at my grandma because she wears funny old glasses :( What do you think I should tell them? Advice please? I am going to get glasses and I am scared because my friend told me the doctor puts so many lights in your eyes for no reason is it true? Thank you, nice video.

    • Hello, Fuzzy! We don’t think it is nice to laugh at anyone’s glasses. How would they feel if the tables were turned, and it was you who laughed at them? We think it is always best to live by the Golden Rule. We have a Wonder about it.

      Wonder #841:What Is the Golden Rule?

      We like glasses, and we think they can be very stylish. Did you know that a lot of styles from the past are getting to be popular today? Your Grandmother could be on the cutting edge of fashion! :-)

      When you go to the eye doctor, be sure to tell them that you are felling a little anxious about the exam. They should be able to walk you through the exam process before you get started. We think this will help you feel better. Good Luck, Wonder Friend! :-)

    • We bet LOTS of Wonder Friends would like to have glasses just like you, Kate! Thanks for sharing your connections to this Wonder! We hope you WONDER with us again soon! :)

    • Thanks for visiting WONDERopolis, Geogia! As we mentioned above, our Wonders are sometimes updated, so the proper way to cite the publishing date is to list the date you visited our page. We hope you enjoyed this WONDER! :)

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Have you ever wondered…

  • Why do some people need glasses?
  • Why is perfect vision called 20/20 vision?
  • What does it mean to be nearsighted or farsighted?

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Try It Out

At some point in time, almost all of us need to get our eyes examined. Use Magenta’s flash cards to prepare for a visit to the eye doctor.

If you or someone you knows wears glasses, they probably lose track of them from time to time. Take a trip to the craft store for a few supplies, and then try making a spec-tacular hand-beaded eyeglass chain, so misplaced glasses become a thing of the past!


Still Wondering

Head on over to Science NetLinks’ Magnify It! lesson to learn about the limits to what the eye can see and how a magnifying glass can help extend those limits.


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