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Precision of snellen eye charts
#1
Hello everybody!
This morning, I was asking me if the snellen test cards that we can find on internet and print on a letter-format sheet are accurate.
I saw that the corresponding letter on differents charts are not always the same size.

I personally use this one:
<!-- m --><a class="postlink" href="http://www.disabled-world.com/artman/publish/eye-chart.shtml">http://www.disabled-world.com/artman/pu ... hart.shtml</a><!-- m -->

But the one on this page have smaller letters:
<!-- m --><a class="postlink" href="http://www.central-fixation.com/resources.php">http://www.central-fixation.com/resources.php</a><!-- m -->

And this one seems okay with the one I use:
<!-- m --><a class="postlink" href="http://www.i-see.org/eyecharts.html">http://www.i-see.org/eyecharts.html</a><!-- m -->

So, does someone here buyed a ''true'' snellen test card? And can you tell me what snellen is the most accurate with a true chart?
What snellen eye chart did you use?

Have a nice day!
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#2
Dear Alex,

Subject: What is the "perfect" size of the letters on a Snellen.

Where ever you obtain your Snellen, you should always check the following:

20/60 must be 1 inch high.

20/20 must be 3/8 inch high.

Measurements should be on a brightly illuminated Snellen.

In metric, the distanc is 6 meters.

20/20 means

6/6 with the letter size 0.9 cm

6/12 means the letter size must be 1.8 cm.

This will callibrate any Snellen -- for legal and personal purposes.

This should duplicate the test conditions in an "office" Snellen or the DMV test.

In general the DMV tests for 20/40 or better. It is indeed a "milestone" to verify in your Bates work that you can clear that line.
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#3
Thank you very much for your answer!
I'll check my snellen when I will have a minute.

Have a nice day of improvement! ;D
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#4
I verified my differents snellen charts and the one that I use have slightly smaller letter than it should be and the one on central-fixation.com have letter that are too small to be accurate. At least, it give letters of different sizes and that's what we need.

Have a nice day!
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#5
I can send you a free chart through E-Mail if you like.
Has a variety of charts in one PDF.
Not perfect sizes but you can print it to size or change on a copier.
mclearsight@aol.com
Also just made a 8x11 Inverted E Pothooks chart.
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#6
Thank you very much but I think I will stay with my current chart that I know by heart. It reduce my strain level to read it.

Have a nice day!
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#7
HOW IT BE POSSITIVELY POSTED WHEN THE YOU HAVE A POOR EYESIGHT!
IS IT NESCESSARY THAT YOU WIL GO TO YOUR DOCTOR AND FOLLOW
AS IT PRESCRIBED..?
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#8
Hello Guys,

Thanks josh24 for your given information.
Ive learned lot of ideas about this topic,
BTW im a new one in this forum.
Thanks a lot,



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