20/20 Vision. 20/10 Vision. 20/40 Vision. What do all these numbers ACTUALLY mean?
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20/20 Vision. 20/10 Vision. 20/40 Vision. What do all these numbers ACTUALLY mean?

Optometrists and ophthalmologists around the world, have discovered the standard by which every person should be judged, when diagnosing their vision status.  20/20 vision is referred to as the standard, or how a “normal” person sees.  This means, that when you stand 20 feet away from an eye chart, you see what the normal person should see.  The American Optometric Association states that a person with 20/20 vision can clearly identify a row of 9mm letters from 20 feet.

Did you know that to be considered legally blind (and also unable to drive a vehicle) in the U.S., your vision is as bad as 20/200?  A legally blind person with vision of 20/200 has to be as close as 20 feet to identify objects that people with normal vision can spot from 200 feet. So a legally blind person needs a distance of two feet to spot the letters on a standard eye chart that is 20 feet away.*

So if you have 20/40 vision, this means that you can see only as good as a normal person can see at 40 feet away from an eye chart.  To clarify this further, if you have 20/40 vision, and there is a normal person standing 40 feet from the chart and you are standing 20 feet from the chart, you both see the same amount of detail on the eye chart.

The reverse applies if you have 20/10 vision.  If you have 20/10 vision you are above average!  You are better than the “normal” person and you have better than what is considered to be standard or normal, vision. If you have 20/10 vision, you can see at 20 feet, what a normal person can see at 10 feet from an eye chart.

Want to test your vision RIGHT NOW?  Cool.  Let’s do it.  Below is an image called the “Snellen Eye Test”.  Here are the steps you can do right now, sitting at your computer, to test your vision.

  1. Measure the LENGTH of the largest “E” on the chart, and multiply that by 2.838.  For example, if you measured the E at 2 inches, you would need to sit approximately 5’8” from the screen.
  2. Scoot your chair back and once you are at the proper distance, start reading the letters starting at the top.  When you reach a line of letters that you cannot read, the line above it will be your approximate vision strength.  Anything worse than 20/20 we can fix!  Call us today!


Image Courtesy eyes-and-vision.com

Did you know that if you lived somewhere like Australia, that you’d call it 6/6 vision?  That’s because they use the metric system down there, it’s 6 METRES instead of 20 FEET.  Centimeters, litres, kilometres… it all sounds a bit strange doesn’t it?

You can get 20/20 vision TODAY from Dr. Ferguson and the specialists at Commonwealth Eye Surgery.  Contact us to find out more about the various types of eye surgery procedures we offer including Lasik, PRK and much more.  You can buy High Definition televisions in any store, but you can’t put a price tag on High Definition vision from Commonwealth Eye Surgery!

*Source: ask.yahoo.com