Author Topic: The Secret of Perfect Vision  (Read 38912 times)

Offline PROH

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Re: The Secret of Perfect Vision
« Reply #60 on: January 29, 2013, 02:56:40 AM »
Hi Steven


I feel it better to have no CYL. Else which ever cyl power you chose (+/-) you will always be favouring a particular direction as compared to its orthogonal one .


Proh

Offline Steven

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Re: The Secret of Perfect Vision
« Reply #61 on: February 18, 2013, 04:39:31 AM »
Tested my vision today, 18 February.
I can see the 20/40 line, all letters.

That means i have -2.

My last prescription was -2.5.

Offline OtisBrown

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Re: The Secret of Perfect Vision
« Reply #62 on: February 19, 2013, 06:06:40 AM »
Hi Steven,

Let me congratulate you!

Success to me is to exceed the 20/40 line (required to drive a car).  It is also to have the "independence of mind" to recognize your own success - or set a "standard" that makes sense to both of us.  Once you see this "initial success" - it should encourage you to continue.  It would encourage *ME* to continue wearing the plus.  Knowing that people like Todd has made himself successful should help you.

I would encourage you to continue to wear the "plus" as a habit, and to prove to yourself that you can do it.  As a matter of *my* judgment, it will take steady wearing of the plus, for about nine months, to get a point where you exceed the 20/25 and 20/20 line.  This is now "pure-personal" to choose to continue.

Thanks - for your success!


Tested my vision today, 18 February.
I can see the 20/40 line, all letters.

That means i have -2.

My last prescription was -2.5.

Offline OtisBrown

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Re: The Secret of Perfect Vision
« Reply #63 on: February 19, 2013, 08:18:59 AM »
Hi Steven,

I spent a lot of time interviewing ODs and MDs. But very few would tell me that the "problem" is not the doctor - it is the person himself.  There is a profound amount of truth in this man's statement.  Success does not depend on the doctor at all.   It depends on the person himself.
As Dr. Prentice states - the person must have strong resolve and intelligence to make prevention "work" for the person.


http://myopiafree.i-see.org/prent.txt

I am often asked about "costs".  If you pay a person for continuous advice, and do not follow the advice -  then true-prevention is VERY EXPENSIVE.  If you have the basic concept and logic, and do-it-yourself, then the "cost" in money - is NOTHING.

The cost in PERSISTENCE - is everything.  I am not a "critic" of a person - but I know that persistence in this effort is VERY DIFFICULT TO INSPIRE IN ANY PERSON.  I hope this helps with your personal quest.

Offline peterg

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Re: The Secret of Perfect Vision
« Reply #64 on: February 19, 2013, 11:35:31 AM »
Congrats Steve.  How do you figure your perscription is -2 based on your accuity testing alone? 

Have you tried to use Frauenfeld's myopia calculator? 
http://frauenfeldclinic.com/focal-calculator/calc.html

I have found the calculator very closely approximates my measured refraction using test lenses, as well as my OD measured perscription.

Tested my vision today, 18 February.
I can see the 20/40 line, all letters.

That means i have -2.

My last prescription was -2.5.

Offline Steven

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Re: The Secret of Perfect Vision
« Reply #65 on: February 21, 2013, 04:39:01 PM »
It's very simple peterg. I found the method myself intuitively. Later i found it was also correct mathematically.

I am going to re-write some of the things i said before. Follow me carefully.

***************************************
According to the standard chart (not in absolute terms).
A person without glasses and with myopia of :

0 = clear image at infinity (nobody has this in absolute terms - nobody can see infinitely small details at infinite distances, at least not in the material universe)

0.25 = clear image at 4 meters.
0.5 = clear image at 2 meters.
0.75 = clear image at 1.3 meters.
1 = clear image at 1 meter.
1.25 = clear image at 80 centimeters
1.5 = clear image at 66 centimeters
1.75 = clear image at 57 centimeters
2 = clear image at 50 centimeters
2.25 = clear image at 44 centimeters
2.5 = clear image at 40 centimeters
2.75 = clear image at 36.36 centimeters
3 = clear image at 33 centimeters
3.25 = clear image at 30.7 centimeters
3.5 = clear image at 28.57 centimeters
3.75 = clear image at 26.66 centimeters
4 = clear image at 25 centimeters

***
You do the above math by dividing 1 with the diopter.
Example : A person with -4.25 myopia can see clear at 1 / 4.25 = 0.235  meaning 23.5 centimeters.

Now the Snellen chart shows the same thing. (not in absolute terms)

20/40 (or 6m/12m) literally means 20 divided by 40 (or 6 divided 12) which equals 0.5 meaning clear image at 50 centimeters (1 divided by 2 diopters = 50 centimeters) -> So you have -2 myopia if you read the 20/40.

20/30 literally means 20 divided by 30 which equals 0.66 meaning clear image at 66 centimeters (1 divided by 1.5 diopters = 66 centimeters) -> So you have -1.5 myopia if you read the 20/30.

20/25 literally means 20 divided by 25 which equals 0.8 meaning clear image at 80 centimeters (1 divided by 1.25 diopters = 80 centimeters) -> So you have -1.25 myopia if you read the 20/25.

20/20 simply means that you see the letters at 6 meters correctly, at that particular size. It also means that if you see the text easily you have in absolute terms a value closer to 0 diopters. If you see the text blurry but still can read some of the letters you have in absolute terms a maximum of -1.

Absolute terms means beyond the chart.
To clarify things please read this short article :
http://www.visionhelp.com/vh_about_13.html

Beyond 20/20 the chart shows the true power of the eye in absolute terms, since with 20/20 you have 0 diopters to a doctor's perspective but in reality the truth is you can never have 0.

In absolute terms :

20/15 = 1.3 meters of perfect image (0.75 myopia)
20/10 = 2 meters of perfect image (0.5 myopia)
20/8 = 2.5 meters of perfect image (0.4 myopia)

The hawk has 20/2 = 10 meters of perfect image (0.1 myopia)

http://en.wikipedia.org/wiki/Visual_acuity

"If the optics of the eye were otherwise perfect, theoretically, acuity would be limited by pupil diffraction, which would be a diffraction-limited acuity of 0.4 minutes of arc (minarc) or 20/8 acuity. The smallest cone cells in the fovea have sizes corresponding to 0.4 minarc of the visual field, which also places a lower limit on acuity. The optimal acuity of 0.4 minarc or 20/8 can be demonstrated using a laser interferometer that bypasses any defects in the eye's optics and projects a pattern of dark and light bands directly on the retina. Laser interferometers are now used routinely in patients with optical problems, such as cataracts, to assess the health of the retina before subjecting them to surgery."

*****

20/5 has never been recorded in human vision.

20/8 has been, but is very rare. It is the best recorded human vision possible.

20/10 isn't even all that common. Is less common, but not all that rare.

20/15 is already better visual acuity than most will ever enjoy. Is even better and is quite common.

20/20 is the standard set as good, normal vision.

Hawks, have been measured at 20/2....hence the phrase, eyes like a hawk. A hawk has 20/2 vision , which is the best in the animal kingdom. 20/10 means you can see at 20 feet what a person with good normal vision can see only when they are 10 feet away.

*****

If you try my values in the calculator you will i see that my math is flawless. For example my edge of blue is now 50 centimeters. If i give a prescription of -2, the calculator will say it is a perfect prescription, according to the 20/20 system of course.

*****

When you naturally reach 20/8 there is no Over-prescription that could make your eyes work like a hawk, because of the human eye limitation. You need to change your eyes with robotic ones.
« Last Edit: February 21, 2013, 04:56:47 PM by Steven »

Offline OtisBrown

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Re: The Secret of Perfect Vision
« Reply #66 on: February 21, 2013, 05:05:01 PM »
Hi Steven,

Of course you are correct in many of these details. 

But equally, some things are not quite true.

For my human eyes - I am practical.  I don't ask for "perfect" vision, because it is not necessary for me.  In fact I fear a strong minus, worn all the time, because the eye adapts to it on a continuous basis - as it does to our "long-term near habit".

I agree that I *MUST* meet the reasonable standard that applies to all of us, and *MUST* personally verify it.  Thus for me, I use a minus lens and the 20/20 line to establish my self-measured refractive STATE.  I do this because I *MUST* be personally responsible to 1) exceed the 20/40 line, and eventually 2) Get close to passing the 20/20 line, and if a pilot, must exceed the 20/20 line.

Thus, if I were at 20/40, (read most of the letters), I would use my Snellen and the MINIMUM minus it takes to just clear the 20/20 line.  With respect, I think you would find that a -1.0 would do that.

Passing the 20/20 line (according to the ODs) means reading 1/2 the letters on the line.  Why is this important.  Because it means I "control" the entire "recovery" process.

I know EACH OF US will have his own idea on how to do this, and if you say you are -2.0 diopters myopic - then I believe you.

But if I were in a program, aimed at "recovery", I would have each person understand this modified measurement approach.  From long experience, it takes about nine months of steady wearing of a plus to get that +3/4 to +1.0 diopter change.  Truly not easy - but possible.

As always, I consider this self-measurement as critical to a person who truly must get to, and exceed the 20/20 line.

Offline peterg

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Re: The Secret of Perfect Vision
« Reply #67 on: February 25, 2013, 10:13:26 PM »

20/40 (or 6m/12m) literally means 20 divided by 40 (or 6 divided 12) which equals 0.5 meaning clear image at 50 centimeters (1 divided by 2 diopters = 50 centimeters) -> So you have -2 myopia if you read the 20/40.


Thanks Steve for all your thorough number crunching. I've only posted the above 20/40 idea you present.

I know I am -1.25D as measured by an OD.   I am also -1.25D if I use test lenses and wish to obtain maximum accuity on my snellon, meaning I don't see blur even if I can't make out the 20/13 line.  I also use my edge of blur distance on the Frauenfeld calculator and get about -1.25 D.  I am generally 20/40 to 20/50 when I make no effort on my snellon.  That's why I wondered why you stated 20/40 made you a -2, given that I definately am not -2 (or worse) given I would approximate myself at 20/45 on the snellon "at rest". 

Offline OtisBrown

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Re: The Secret of Perfect Vision
« Reply #68 on: February 26, 2013, 04:59:33 AM »
Hi Peter and Steven,

I think your ideas are important!    I know that the ODs feel that they *must* give you 20/13 vision - or they are incompetent.  Perhaps you judge them that way also. 

But when you study the effect of a -3 diopters lens on the natural eye - and the eye's response (it becomes myopic because of that minus lens) you must understand why *I* fear the wearing of a minus lens.   I would rather have 20/25 to 20/30 for life (and wear a plus correctly), than to get 20/13 with a -2.5 diopter minus lens.  But this is indeed a personal choice.

If you measure your refractive STATE my way, it would take about a - 3/4 to -1.0 to "just clear the 20/20 line.  Since my goal would be "close to" 20/20, then wearing a plus for all close work, and monitoring my *own* Snellen, I could judge my own success myeself.  Once above 20/40 - prevention is under my complete control. 

But equallly, I understand that all but the most motivated (pilots who MUST have 20/20) simply will not wear the plus with the force and intensity required to achieve that result.  That last "step" into 20/20, it exclusively a personal responsiblity - in my opinion.  I congratulate both of you on your success - and thank you for your review.

Otis



20/40 (or 6m/12m) literally means 20 divided by 40 (or 6 divided 12) which equals 0.5 meaning clear image at 50 centimeters (1 divided by 2 diopters = 50 centimeters) -> So you have -2 myopia if you read the 20/40.


Thanks Steve for all your thorough number crunching. I've only posted the above 20/40 idea you present.

I know I am -1.25D as measured by an OD.   I am also -1.25D if I use test lenses and wish to obtain maximum accuity on my snellon, meaning I don't see blur even if I can't make out the 20/13 line.  I also use my edge of blur distance on the Frauenfeld calculator and get about -1.25 D.  I am generally 20/40 to 20/50 when I make no effort on my snellon.  That's why I wondered why you stated 20/40 made you a -2, given that I definately am not -2 (or worse) given I would approximate myself at 20/45 on the snellon "at rest". 

Offline johnlink

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Re: The Secret of Perfect Vision
« Reply #69 on: February 26, 2013, 10:35:35 AM »

20/40 (or 6m/12m) literally means 20 divided by 40 (or 6 divided 12) which equals 0.5 meaning clear image at 50 centimeters (1 divided by 2 diopters = 50 centimeters) -> So you have -2 myopia if you read the 20/40.


While all the arithmetic is correct, I doubt the truth of the assertion that 20/40 is equivalent to being able to focus clearly at 0.5 meters. Why not 0.5 feet, or 0.5 inches? The fraction 20/40, if it can even be considered a fraction, is 20 feet/40 feet which is equal to the dimensionless number 0.5. So I see no reason whatsoever to expect that just clearing the 20/40 line implies myopia of -2.0.
« Last Edit: February 26, 2013, 10:44:46 AM by johnlink »

Offline johnlink

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Re: The Secret of Perfect Vision
« Reply #70 on: February 26, 2013, 10:44:08 AM »

I also use my edge of blur distance on the Frauenfeld calculator and get about -1.25 D.


What is the Frauenfeld calculator?

Offline OtisBrown

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Re: The Secret of Perfect Vision
« Reply #71 on: February 26, 2013, 11:41:20 AM »
Hi John,
I personally admit that prevention is truly difficult.  I set my goal as always reading the 20/40 line.  I will use a -1/2 or a -1.0 to find out the minimum amout of minus it takes to just-clear the 20/20 line.  That will normally take about a -1.0 diopter lens.

But if I confirm that I pass all reaquired DMV tests (read 20/40) then why would I wear a -2.5 diopter lens all the time? 

This is they type of "error" an OD in an office will give you.  I consider it deadly - which is why I measure my refractive STATE myself.  I trust what *I* measure, more than an -2.5 diopter lens some OD might "prescribe".  But equally, and from past judgment, it does take a LONG TIME of consistent "plus wearing" to get your REFRACTIVE STATE to change by +3/4 to +1.0 diopters - there-by giving you 20/20 (but PERSONAL VERIFICATION.

I believe I had establishished and exact relationship, between visual acuity and refractive STATE.  At least I know what I am doing, and trust my results.  That is better solution - than to go to an OD, and get a destructively over-prescribed miinus from an OD. 

As an engineer, I finally concluded that no one is interested in my long-term vision - other than myself.

Offline OtisBrown

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Re: The Secret of Perfect Vision
« Reply #72 on: February 26, 2013, 11:47:46 AM »

Hi John,

Herer is the Frauenfeld Calculator:

http://frauenfeldclinic.com/myopia-calculator/

I obviously believe the Snellen/Trial-lens check - gives me best knowedge, and full control.

This includings obtaining $10 (minus) driving glasses if I have 20/50 to 20/60 vision.  (As a temporary measure - until I begin to exceed the 20/40 line.)

Since my intention is to change my refractive STATE by +1/2 diopter, and pass the 20/40 line, I truly do not want to spend $200 for glasses - that I will not need anymore when I exceed the 20/40 line. This knowledge and ability - gives *me* control of my visual future.



I also use my edge of blur distance on the Frauenfeld calculator and get about -1.25 D.


What is the Frauenfeld calculator?

Offline johnlink

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Re: The Secret of Perfect Vision
« Reply #73 on: February 26, 2013, 11:52:38 AM »

Offline johnlink

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Re: The Secret of Perfect Vision
« Reply #74 on: February 26, 2013, 11:59:05 AM »
Actually the link above goes to a page that has a link to the calculator. HERE is where the calculator is found:

http://frauenfeldclinic.com/focal-calculator/calc.html