Subject: To measure your own visual acuity, you need to measure it yourself with these charts.
Here are two “Eye Charts” or Snellens you can use at 20 feet.
Block Letter Snellen Chart.
Click to access block_letter_eye_chart.pdf
It is very important that this be permanent – and that you put a bright light on it.
Vision varies quite a bit – so long-term monitoring is required to get a reasonable judgment – of your visual acuity.
Myopiafree 
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“Discussion”
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