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how to convert snellen into diopters
#1
How to convert the snellen fraction into diopters?
can someone tell me please, thanks.
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#2
vst Wrote:How to convert the snellen fraction into diopters?
can someone tell me please, thanks.

I use this rule instead:
If you can see text at a distance of 1m from for instance the computer then you have 1 diopter. If you can see text at a distance of 0.5m from the computer then you have 2 diopters. If you can see text at a distance of 0.25 m from the computer then you have 4 diopters and so on.
So I use diopters at near distance, but at far distance I guess the snellen fraction is better. I usually do exercises at near distance so it suits me rather well.
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#3
hammer Wrote:
vst Wrote:How to convert the snellen fraction into diopters? can someone tell me please, thanks.

I use this rule instead: If you can see text at a distance of 1m from for instance the computer then you have 1 diopter. If you can see text at a distance of 0.5m from the computer then you have 2 diopters. If you can see text at a distance of 0.25 m from the computer then you have 4 diopters and so on. So I use diopters at near distance, but at far distance I guess the snellen fraction is better. I usually do exercises at near distance so it suits me rather well.
@hammer - But you have to specify the size of the text as well. So, for instance, today as I sat in my parked car at 7:40AM facing south on a mostly sunny day, I noticed that the license plate of the car in front of me had large blue lettered words which I could read, but had much smaller blue lettered words in the top corners which I could not read. I estimated the distance to the license plate to be about seven feet (although there were two angles involved; let's see: 7' base, 4' height, = X' hypoteneuse, X = ? plus sideways: 7' base, 2' width, = Y hypoteneuse, Y=? Anybody?Anybody?Beuller?)
Anyway, I set myself the task of correcting my visual system alignment so that the light reflecting from those top corner words could be focused onto my foveas so I could read them.
I first saw that there were three words stacked on each other and each corner had the same words. By carefully adjusting the positioning and direction of my eyes and face (and even my torso a bit) I began to see clearly after about 5 minutes that the middle word was WINDOW. A few more minutes of adjustments and I clearly saw the bottom word was STICKER. But I could not get the top word. I stuck with it though and after another 10 minutes of adjustments and blinking and relaxing I finally saw that it was a three letter word and the last two were EE. And then I shifted until I read it clearly: SEE.
I measured those words' letters at 1/4 inch.
What was my vision's comparable snellen measurement during that clear vision event/flash?
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#4
JMartinC4 Wrote:
hammer Wrote:
vst Wrote:How to convert the snellen fraction into diopters? can someone tell me please, thanks.

I use this rule instead: If you can see text at a distance of 1m from for instance the computer then you have 1 diopter. If you can see text at a distance of 0.5m from the computer then you have 2 diopters. If you can see text at a distance of 0.25 m from the computer then you have 4 diopters and so on. So I use diopters at near distance, but at far distance I guess the snellen fraction is better. I usually do exercises at near distance so it suits me rather well.
@hammer - But you have to specify the size of the text as well. So, for instance, today as I sat in my parked car at 7:40AM facing south on a mostly sunny day, I noticed that the license plate of the car in front of me had large blue lettered words which I could read, but had much smaller blue lettered words in the top corners which I could not read. I estimated the distance to the license plate to be about seven feet (although there were two angles involved; let's see: 7' base, 4' height, = X' hypoteneuse, X = ? plus sideways: 7' base, 2' width, = Y hypoteneuse, Y=? Anybody?Anybody?Beuller?)
Anyway, I set myself the task of correcting my visual system alignment so that the light reflecting from those top corner words could be focused onto my foveas so I could read them.
I first saw that there were three words stacked on each other and each corner had the same words. By carefully adjusting the positioning and direction of my eyes and face (and even my torso a bit) I began to see clearly after about 5 minutes that the middle word was WINDOW. A few more minutes of adjustments and I clearly saw the bottom word was STICKER. But I could not get the top word. I stuck with it though and after another 10 minutes of adjustments and blinking and relaxing I finally saw that it was a three letter word and the last two were EE. And then I shifted until I read it clearly: SEE.
I measured those words' letters at 1/4 inch.
What was my vision's comparable snellen measurement during that clear vision event/flash?

You shall see crystal clear on that distances.
Then you notice that your eyesight can easily change from for instance 4 diopters to 1 diopter, at least this is the case for me.
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#5
Thanks
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#6
JMartinC4 Wrote:... today as I sat in my parked car at 7:40AM facing south on a mostly sunny day, I noticed that the license plate of the car in front of me had ...blue lettered words in the top corners which I could not read. I estimated the distance to the license plate to be about seven feet (although there were two angles involved; let's see: 7' base, 4' height, = X' hypoteneuse, X = ? plus sideways: 7' base, 2' width, = Y hypoteneuse, Y=? ...) Anyway, I set myself the task of correcting my visual system alignment so that the light reflecting from those top corner words could be focused onto my foveas so I could read them. I first saw that there were three words stacked on each other and each corner had the same words. By carefully adjusting the positioning and direction of my eyes and face (and even my torso a bit) I began to see clearly after about 5 minutes that the middle word was WINDOW. A few more minutes of adjustments and I clearly saw the bottom word was STICKER. ...after another 10 minutes of adjustments and blinking and relaxing I finally saw that [the top word] was a three letter word and the last two were EE. And then I shifted until I read it clearly: SEE. I measured those words' letters at 1/4 inch. What was my vision's comparable snellen measurement during that clear vision event/flash?
As I parked this morning I realized everything was the same except for the time of day - 9AM. The sun was just more to my left. So I figured I should be able to use the same Bates Methods to read the same words - faster now since I've done it before - but I could not do it. Not after 5 minutes, 10 minutes, 20 minutes. There was one brief moment where the words got a touch sharper but that was it. Why couldn't I duplicate my results? I noticed that my estimate of the height and width distances to the license plate was too much by half - those angles were much smaller than I'd remembered - but that didn't make any difference since they were still the same as yesterday. I tried adjusting more to the sunlight - barely noticeable improvement. I did all the same methods as yesterday but failed to see the words. Finally I gave up. I got out and saw - I was parked a good foot (12 inches) further away! I got back in and reparked. I performed the methods again. The words came in sharp and clear within about 5 minutes. It was awesome.
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#7
JMartinC4 Wrote:
JMartinC4 Wrote:... today as I sat in my parked car at 7:40AM facing south on a mostly sunny day, I noticed that the license plate of the car in front of me had ...blue lettered words in the top corners which I could not read. I estimated the distance to the license plate to be about seven feet (although there were two angles involved; let's see: 7' base, 4' height, = X' hypoteneuse, X = ? plus sideways: 7' base, 2' width, = Y hypoteneuse, Y=? ...) Anyway, I set myself the task of correcting my visual system alignment so that the light reflecting from those top corner words could be focused onto my foveas so I could read them. I first saw that there were three words stacked on each other and each corner had the same words. By carefully adjusting the positioning and direction of my eyes and face (and even my torso a bit) I began to see clearly after about 5 minutes that the middle word was WINDOW. A few more minutes of adjustments and I clearly saw the bottom word was STICKER. ...after another 10 minutes of adjustments and blinking and relaxing I finally saw that [the top word] was a three letter word and the last two were EE. And then I shifted until I read it clearly: SEE. I measured those words' letters at 1/4 inch. What was my vision's comparable snellen measurement during that clear vision event/flash?
As I parked this morning I realized everything was the same except for the time of day - 9AM. The sun was just more to my left. So I figured I should be able to use the same Bates Methods to read the same words - faster now since I've done it before - but I could not do it. Not after 5 minutes, 10 minutes, 20 minutes. There was one brief moment where the words got a touch sharper but that was it. Why couldn't I duplicate my results? I noticed that my estimate of the height and width distances to the license plate was too much by half - those angles were much smaller than I'd remembered - but that didn't make any difference since they were still the same as yesterday. I tried adjusting more to the sunlight - barely noticeable improvement. I did all the same methods as yesterday but failed to see the words. Finally I gave up. I got out and saw - I was parked a good foot (12 inches) further away! I got back in and reparked. I performed the methods again. The words came in sharp and clear within about 5 minutes. It was awesome.


I do this little trick. I know there are automatic eye movements that scans for instance an area of a detail. Ok, then as my poor I is bad at scanning areas I will fail when it comes to read such texts that you JMartinC4 tried to read. What do I do then, ok, then I instead look at areas where there are no special details at all, for instance look under the car in front of you to see if there is a cat there hideing, or detect what ever there that hides, well you've got what I meant, by doing so I have activated the automatic eye movements to search and scan for things that hide. Ok, then afterwards look at those words again and discover that they are clearer. I do this searching for hidden details method rather a lot and I think it relaxes my eyes such that I do not have to do any extra palming so much, but keep in mind that you shall look at a point that is between two other a bit more near objects in order to activate the 3D effect. Trees or bushes are excellent to look at.
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#8
hammer Wrote:I do this little trick. I know there are automatic eye movements that scans for instance an area of a detail. Ok, then as my poor I is bad at scanning areas I will fail when it comes to read such texts that you JMartinC4 tried to read. What do I do then, ok, then I instead look at areas where there are no special details at all, for instance look under the car in front of you to see if there is a cat there hideing, or detect what ever there that hides, well you've got what I meant, by doing so I have activated the automatic eye movements to search and scan for things that hide. Ok, then afterwards look at those words again and discover that they are clearer. I do this searching for hidden details method rather a lot and I think it relaxes my eyes such that I do not have to do any extra palming so much, but keep in mind that you shall look at a point that is between two other a bit more near objects in order to activate the 3D effect. Trees or bushes are excellent to look at.
Me no likey 'tricks'. Me likey science. Me standy in front of wall map. Can ready little letters goody. Then me movey back a little until wordies blur. Then me turn head to right until bad blurrier left eye GETS WORDIES FOCUSED ONTO FOVEA AGAIN - now wordies clear again! Foveas good; pseudo foveas bad.
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#9
Okay, that was immature of me. An immature reaction to an (perceived) immature response. Forgive me!
Returning to my example, I went out to my car after work, around 6PM, eagerly expecting to quickly duplicate and verify my morning experiences. But I was disappointed again. First, I measured the actual distance to the license plate and found it to be 8 feet not 7 feet as estimated. Great! But the sun was going down now, more shade, distractions, etc. It again took a good 20-plus minutes before I could finally get the words SEE WINDOW STICKER into sharp clarity. Frustrating. But I did do it.
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#10
I was fortunate enough to test the same setup this morning at 8:40AM. Same results. One significant difference is that the initial appearance now of the corner words is only maybe half as blurry as when I first began the trial and error experiment three days ago. But it still takes about 20-plus minutes to get them sharp and clear. Frustrating. Something else I realized from this test is that because the blur doesn't differentiate by distance, I have simply never known whether I should be able to see something clearly or not - at any distance beyond 10 or 20 feet probably. So for instance, on the second day, the words were just as blurry from 9' as they were from 8' - but I didn't realize it was physically impossible for my eyes to focus the 1/4" letters from what I thought was 8' (where it is possible). Which means nearsighted people using Bates to improve our eyesight outside probably waste a lot of time trying to improve blur which is impossible to improve at certain distances.
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#11
JMartinC4 Wrote:Me no likey 'tricks'. Me likey science. Me standy in front of wall map. Can ready little letters goody. Then me movey back a little until wordies blur. Then me turn head to right until bad blurrier left eye GETS WORDIES FOCUSED ONTO FOVEA AGAIN - now wordies clear again! Foveas good; pseudo foveas bad.

Ok fellow, lets analyse this to get something good out of it.
You eventually relax and get immature, because being mature also means a lot of strain and worries,
no problem, that is good for vision, continue with a smile and I let you know something here that might help you Wink :
In this immature state you explain what shifting really means and what the catalyst is behind it,
even if it is not obvious in the straight context of the message.
Now, this is interesting because what you state is something that your relaxed unconscious mind states without you being actually aware of what you wrote, actually you afterwards excused your relaxed state which of course is a catalyst for your bad eyesight, just made you aware of it, excuse me Wink .
Ok, your relaxed mind says that shifting is a way to synchronize the eyes together, that sounds good, that is true.
You do it by turning the head slightly to right while looking at the object and thus get an oblique angle to the object.
Then your right eye gets dominant.
Then you turn your head to the left and look straight on the object.
Then both eyes are equally dominant.
Then you turn your head slightly to left while looking at the object and thus get an oblique angle to the object.
Then your left eye gets dominant.
So by doing this shifting you actually shift the eye dominance also, that is a big step to get better eyesight.

Ok, this explains why shifting short distances (central fixation and so on) are good for synchronizing the eyes together, and thus it is good for your distance perception.

My old biology teacher told me a story when we studied the vision:
This biology teacher had very good eyesight, he could detect and see birds very very far away, and I remembered that I had problems even to see those birds even if I knew where they were up in the sky.
Actually he was also employed working also as a person that counted birds in the sky for scientific reasons.
The story was something about an electrician who turn his head left right (and so on) in order to be able to see (focus) where the screw was as he handled the screw driver.
Because he got a better stereo 3D vision by doing that and thus he could work more easily.
Something like that, might be wrong english here, but no worries, 90% is body language.
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#12
vst Wrote:How to convert the snellen fraction into diopters?
can someone tell me please, thanks.

VST,
Here is some answer to your original question Smile :
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#13
hammer Wrote:Ok, your relaxed mind says that shifting is a way to synchronize the eyes together, that sounds good, that is true. You do it by turning the head slightly to right while looking at the object and thus get an oblique angle to the object. Then your right eye gets dominant.
Then you turn your head to the left and look straight on the object. Then both eyes are equally dominant. Then you turn your head slightly to left while looking at the object and thus get an oblique angle to the object. Then your left eye gets dominant.
So by doing this shifting you actually shift the eye dominance also, that is a big step to get better eyesight.
Ok, this explains why shifting short distances (central fixation and so on) are good for synchronizing the eyes together, and thus it is good for your distance perception.
My old biology teacher told me a story when we studied the vision: This biology teacher had very good eyesight, he could detect and see birds very very far away, and I remembered that I had problems even to see those birds even if I knew where they were up in the sky. Actually he was also employed working also as a person that counted birds in the sky for scientific reasons. The story was something about an electrician who turn his head left right (and so on) in order to be able to see (focus) where the screw was as he handled the screw driver. Because he got a better stereo 3D vision by doing that and thus he could work more easily. Something like that, might be wrong english here, but no worries, 90% is body language.
NOW you're talkin', hammer! It's Hammer Time!! Good restatement. The unnatural unequal mistimed neonatal blur causes unbalanced eye dominance, which causes misalignment, which creates pseudofoveas, which causes nearpoint fixation. Reversing the unbalanced eye dominance reverses the misalignment resulting in improved ability to use the foveas, resulting in redevelopment of normal eyesight.
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#14
JMartinC4 Wrote:The unnatural unequal mistimed neonatal blur causes unbalanced eye dominance, which causes misalignment, which creates pseudofoveas, which causes nearpoint fixation. Reversing the unbalanced eye dominance reverses the misalignment resulting in improved ability to use the foveas, resulting in redevelopment of normal eyesight.

Yes, I now eventually get your neanatal thinking, JMartinC4 rocks !!
But, in more simple general terms:
Looking straight ahead on an object fails, because the mind is clueless of what the orientation of straight ahead really is.
When mind/vision gets relaxed enough the rest position of the eyes however gets reestablished and that straight ahead direction reference gets refixed naturally. If people realize this then they are more likely to improve their vision.
They instead call it nosefeather, but what the heck does that name nosefeather tell people about the real cause of why they shall actually use the nosefeather temporarily or the neonatal insights they actually rather would have needed as a base.
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