Snellen Chart Help (Used Online one)

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jayboi2005
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Snellen Chart Help (Used Online one)

Postby jayboi2005 » Mon 17 Apr 2006 6:15 pm

Ok i did a quick test with the online snellen chart, im not too sure what it means because of my distance away and all that. Maybe someone can shed some light.

This is what i did, loaded the online snellen on this website, i sat exactly 1m away from the chart and could read ever single line apart from the last one. I never used to be able to do that! What does it mean is basically what im asking, what can you read at 1m? :roll:


Online Snellen Chart
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GarethB
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Postby GarethB » Mon 17 Apr 2006 7:34 pm

John did one you could download and print. Then if you put thta on a wall 3m away you would then have a clos approximation as to wat your current sight level would be.

The other one John had on this sight, do not know if it is still here sice he did his upgrade, but that was more to see how your sight changed throughout the day. This meant that you would need te screen at the same resolution and sit the same distance away each time.

The number of lines you could read was irrelevent if you wanted to comapre it with a proper eye test.
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Postby jayboi2005 » Mon 17 Apr 2006 7:48 pm

Ok on the downloadable Snellen chart that you stick on the wall, and stand 3m away i have 20/20 vision with both eyes together. Each eye on its own well don't ask its terrible. So what is 20/20 in UK terms and is it driving standard? :?
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Postby John Smith » Mon 17 Apr 2006 7:53 pm

Jayboi,

20/20 is 6/6. I.e. "normal" vision.
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Postby jayboi2005 » Mon 17 Apr 2006 8:00 pm

urm, are you sure? Is that snellen chart correct?

http://www.keratoconus-group.org.uk/snellens/Snellen_3m_A4.pdf

20/20 is 6/6 and thats correct?
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Postby GarethB » Mon 17 Apr 2006 8:14 pm

When you print it you just get the letters, but if you copy the information across from the pdf, then it gives the imperial and metric equivelents.

Green arrows at 6/12 (20/40) is the driving standard.

Red arrows is 6/6 (20/20) letters are PHUNTDZ.

Line below is if you have better that the recgnised norm 6/4.5 (20/15). If you read that, then you are seeing at 6 meters what you should see at 4.5 meters.

Johns chart is correct, but only if it's printed at normal size and put at eye level on a wall 3 meters away.
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Postby jayboi2005 » Mon 17 Apr 2006 8:23 pm

hmm i really don't understand, i got the tape measure out now measured exactly 3m and checked the align and size my printer prints and done the whole thing again whilst getting yet again i can see 20/20 i couldn't before i don't understand why i can now. Im not saying it is all clear down at 20/20 but i can see to know what i am looking at. :roll:
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Postby jayuk » Mon 17 Apr 2006 8:34 pm

I think the distances need to be multiplied by 2....remember that when you get an eye test in the opticians you are looking in the mirror which is reflecting..thus double the real distance........
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Postby Anne B » Mon 17 Apr 2006 8:41 pm

That makes my eyesight worse then!!
I did have the printable version up in my kitchen for a while, but got fed up with everyone coming round showing me how well they could read the chart!

One bad eye day , it got binned.
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Postby jayboi2005 » Mon 17 Apr 2006 8:47 pm

jayuk wrote:I think the distances need to be multiplied by 2....remember that when you get an eye test in the opticians you are looking in the mirror which is reflecting..thus double the real distance........


Now im more confused. So does this mean my vision isnt really 20/20?
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