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Snellen Chart – Standard test for visual acuity in 20/x format

Posted on September 15th, 2013 Dan

From http://www.mdsupport.org/snellen.html






If you want to take this test in an unbiased way, shrink your browser window to avoid looking at the chart below before you’re ready…






To properly view the chart on your monitor:

  • Measure the height of the letter A in millimeters.
  • Divide by 88.
  • Multiply by 6.

The final number is the distance (in meters) that you should stand from the monitor.  To increase or reduce viewing distance, use ctrl +/- in the browser and recalculate.



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