Let me state that I greatly appreciate Todd's success. I will not attempt to "explain" it - except to say that I am pleased he personally verified his vision as passing the State required DMV test. I will also state that I have seen profound over-prescription of from -1 to -4 diopters (that I documented with Todd - by mailing him the information).
The chart you develop assumes that OD make ACCURATE MEASUREMENTS. I found that totally wrong. What they do is to "crank up" on their Phoropters - as hard a possible - and give you a very strong minus. That FIRST over-prescribed minus - (in my opinion) kills you distant vision. When *I* argue to get out of it, I assume the person can read the 20/60 line with no minus lens on his face. In that range, there is evidence that the person can get to 20/40 in about six to eight months. For another six months of wearing a plus, he could "make" 20/20, and positive status.
I do not enjoy being the "bearer of bad news" - but I try to be as fair minded as possible. I don't make "claims" beyond the above statements.
If you are taking about self-measured CHANGE, then, given this statement, you would have to get a positive change of +1.5 diopters - and that would take about one year - in my judgment.
Otis i still didn't managed to test a pair of 1.5 but with the -1.25 squinting only i could read 20/50.
Otis> Using a Snellen and a "test minus" is the only accurate measurement system you have.
Right now since i am looking for a job, i am still deciding what glasses i would need for the potential job.
Otis> I GAVE UP DEALING WITH ODS. They are just not "worth it". If you want a "correct" lens, then, if you are an engineer, and prepared to do everything yourself - the this is what I would do.
1) Get about four "test lenses", of -1/2, -1, -2 and -3, from Zennioptical.com
2) Look at your Snellen, and hold each one up. Find one that clears the 20/30 to 20/25 line. Then order that lens strength from Zenn.
3) I am tired of paying ODs $250 and $150 for glasses. This is what I would do.
4) In my judgment this is NOT MEDICINE, it what I DO.
If it's a job where i will only use the computer then i would get a very low prescription like -1.25 or -1.5.
If the job demand more i could get something around -2.
Otis> Getting these test-lenses is the key. They cost about $4 each. But it takes a wise determined person to do it.
Otis> I -2 D would probably meed most of your needs. For driving a car, you choose a lens that gives you 20/30 to 20/20 vision. (Always meet the legal requirement.
Otis> Here is a video on how to order lenses from Zenni.http://www.youtube.com/watch?v=N_u39cB27bg
Otis> Here is how I use a lens to measure my refractive state.http://www.youtube.com/watch?v=K7cU-0onSvI
Otis> In your case, you would find the WEAKEST minus to give you "just" 20/40 to 20/30.
Otis> I "draw the line" and insist that this is NOT MEDICINE, and NOT A MEDICAL MEASUREMENT. It is science and self-measurement of my refractive STATE.
Otis> If you decide to continue - let us know.
Otis> I "arm twisted" my nephew (when he was 14 years old) to BEGIN the use of a plus 2 - when he was SLIGHTLY nearsighed. I had no desire to see him have his vision DESTROYED WITH A MINUS.
Otis> He knew I told the truth. So he would the plus through college, always passing the DMV, and never had to "deal" with an OD in an office. He is now over 40 years old - and kept it that way. He KNOWS how difficult it is to "keep motivated".
Otis> If you decide to go "down this path" - let me know.
A person without glasses and with myopia of :
0 = clear image at infinity ?