Interpreting Snellen

[Shambles]

I have started to use Snellen charts, I have a few questions.

I can read the 20/60 line but its not clear... I mean I can read the big E 20/200 even then its not crystal clear.

Only time I can actually see them 'clearly', like fine precise edges is when I get a very good flash.

I guess my question is, if you can guess/interpret a letter does that mean you can read it/passed that line.

[clarknight]

http://www.youtube.com/watch?v=863yFmc-Ius
http://www.youtube.com/watch?v=mYpsYPPV_hg

[FIAT2LUX]

The farthest line that you can interpret the letters for half of that line is what your Sbellen acuity is. When I got prescribed my glasses, I could read the 20/15 line. I didn't see it crystalline clearly though, and rarely can someone see that much perfectly clear (btw, that's the -4 lenses that I don't use). So let's say you can read the big E on the chart and it's 20/200. You can read all the way down to the 20/70 line and can sort of guess based on what you see, half the letters on the 20/60 line, but no more. That means you have 20/60 acuity. That's how the eye doctors use it.

[Nini]

When I look at the eye-chart, I can see my 'state of relaxation' and 'central fixation':

When I am not relaxed, even all the big letters are blurry, although I can read part of them.
When I am very relaxed, then I see - automatically - in the right way and the letters appear completely clear and black against the white background till the 20/50 line including; the 20/40 line is readable, but not as clear and parts of the next 2 lines below I can also make out.
When I practice central fixation being (initially) relaxed or not, it is even a bit better and sometimes the beginning and the end of the 20/20 line becomes clear.

[Shambles]

The farthest line that you can interpret the letters for half of that line is what your Sbellen acuity is. When I got prescribed my glasses, I could read the 20/15 line. I didn't see it crystalline clearly though, and rarely can someone see that much perfectly clear (btw, that's the -4 lenses that I don't use). So let's say you can read the big E on the chart and it's 20/200. You can read all the way down to the 20/70 line and can sort of guess based on what you see, half the letters on the 20/60 line, but no more. That means you have 20/60 acuity. That's how the eye doctors use it.

Thanks.

You can read the 20/15 line that sounds like some vision improvement! It could also have been some over prescription.

I guess I should thank my eye doc , I dont think he ever really over prescribed me.

[FIAT2LUX]

Shambles,

That was totally overprescription. I've had improvement and a few 20/20 flashes, but I am not that far on my own eyes. Also, I guess that would be pretty nice that your eye doc doesn't overprescribe. Yay for that!