How do you mathematically convert a script taken w/ a minus phoropter to plus phoropter measurements

Discussion in 'Optometry Archives' started by DarkProtoman, Jul 21, 2007.

  1. DarkProtoman

    DarkProtoman Guest

    How do you mathematically convert a script taken using a phoropter w/
    minus JCC lenses to plus cylinders? I mean, how do you write a script
    that uses a plus cylinder lens instead of a minus?
    Like, these two scripts are equivalent, but one uses a minus cylinder,
    and the other uses plus cylinders:

    Sph: +2.00; Cyl: +1.00; Axis:090
    Sph: +3.00; Cyl: -1.00; Axis: 180

    Like, write this using plus cylinders:

    OD: Sph: -3.00; Cyl: Sph; Axis: Bal.; Prism: Bal.
    OS: Sph: -3.75; Cyl: -1.00; Axis: 168; Prism: 0

    DarkProtoman, Jul 21, 2007
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  2. DarkProtoman

    Dave Bell Guest

    I'd like to see if I understand the conversion correctly, eben though I
    don't really know what I'm doing, so:

    -3.75 / -1.00 @ 168 becomes
    -4.75 / +1.00 @ 75

    Is that right?

    Dave Bell, Jul 21, 2007
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  3. DarkProtoman

    otisbrown Guest

    The formula is:

    add the sphere power to the cylinder power (1st and 2nd
    numbers) for a new sphere total, reverse the sign of the cylinder
    power, add or subtract 90 (so the new number is less than or equal
    to 180) for the new axis.
    otisbrown, Jul 21, 2007
  4. DarkProtoman

    DarkProtoman Guest

    I'm not so sure about that, since it came from you...

    Anyone else to confirm/disafirm?
    DarkProtoman, Jul 21, 2007
  5. od -300
    os -475 +100 x 78
    michael toulch, Jul 21, 2007
  6. DarkProtoman

    Dave Bell Guest

    Umm, yeah. I meant 78 degrees.
    I may have been reading that as 165, not 168. I hope.

    Dave Bell, Jul 22, 2007
  7. DarkProtoman

    CatmanX Guest

    WTF do you want this crap for? No-one uses plus cyl - except for some
    stupid ophthals. All labs grind in minus cyl form, i.e. cyl ground on
    the back surface, and have done so for the past 40 years. Anyone
    writing scripts in plus cyl form is an idiot as it MUST be converted
    at some point to make the Sx. This adds to error and the wrong script
    being made.
    CatmanX, Jul 22, 2007
  8. DarkProtoman

    otisbrown Guest

    Dear Catman,

    Subject: Your respect for OPHTHAMOLOGISTS, and
    their opinion.

    CatMan> WTF do you want this crap for? No-one uses plus cyl - except
    for some stupid ophthals.

    Otis> I am certain these ophthmolgists will be highly
    impressed by your statements about them.
    otisbrown, Jul 22, 2007
  9. DarkProtoman

    otisbrown Guest

    Again, Mike you LEAP to the wrong (and your exclusive)

    I have great respect for ophthamologist -- in the context
    of medicine.

    Further, I do not use the foul language that CatMan uses.
    I may disagree with a man concerning his opinion on
    a subject -- but I do not disrespect him -- as CatMan
    does on a continuous basis.

    otisbrown, Jul 22, 2007
  10. DarkProtoman

    CatmanX Guest


    You are a waste of space Cletis.

    As explained already, plus cyl notation is wrong, outdated and
    technically invalid. ANyone using plus cyl notation is writing an
    incorrect script as lenses can't be made for these scripts.

    Do I need to further explain this to your tiny brain????
    CatmanX, Jul 22, 2007
  11. DarkProtoman

    DarkProtoman Guest

    I just wondered about what the formula was.
    DarkProtoman, Jul 22, 2007
  12. DarkProtoman

    otisbrown Guest

    Dear Mike,

    You indeed have your OPINION, that the fundamental
    eye will not change its refractive STATE when
    you place a -3 diopter lens on it.

    I think your concept of the natural eye is a scientific
    failure -- and disproven to boot.

    There are ophthamologists who agree that it
    would be WISE for the person to begin using
    the plus (at the threshold) to keep their
    vision clear doing the school years.

    But the real issue is whether the person himself
    is willing to make that type of commitment.

    And that is indeed the point.

    Obvously "Brainy" is not a candidate for
    prevention, by ANY METHOD -- Bates,
    plus, or a combination of the two.

    So she loves that minus lens -- and does
    not want to be disturbed by "contrary" scientific

    Yeah, you and Brainy were made for each other.

    At least the Bates people have a more open
    mind that you do towards PREVENTIVE methods.

    Just one man's opinion.

    otisbrown, Jul 22, 2007
  13. DarkProtoman

    Neil Brooks Guest

    Nice straw man argument, Uncle Otie: arguing against something that
    NOBODY said.

    Does that make you feel special -- sort of like your Librium??

    DO you only find it possible to argue against things that you make up,
    rather than argue against the ACTUAL position of a person?

    It would appear so.
    Do you mean monkey eyes? Nobody here really talks about those but
    Really? Who, where, are they still practicing, and have they ever
    done any controlled testing?

    Are you off your meds again? Gosh, I hope not.
    So your myopic niece, Joy Benson, is just a lazy slug? That's not a
    very nice thing to say about your own niece, Uncle Otie, now is it?
    Neil Brooks, Jul 22, 2007
  14. DarkProtoman

    Dan Abel Guest

    Is that because they both have IOLs and are long past the age where
    there is possibility of improvement?
    Dan Abel, Jul 22, 2007
  15. DarkProtoman

    Salmon Egg Guest

    If you have to ask, I would not be able to answer you at your level. If you
    know anything about optics and anything about simple algebra, and one more
    thing, it should be a snap. The one thing is that a cylindrical lens with
    power P and another cylindrical lens oriented perpendicular to the first is
    optically the same as a spherical lens of power P.

    Salmon Egg, Jul 22, 2007
  16. DarkProtoman

    otisbrown Guest

    Good point, Mike.

    You can add that if you do anything SLIGHTLY different AT ALL,
    one pointed-headed person (you know who) will post
    CHARGES against you. That alone will prevent
    STEPS --at all.

    Yes, Mike I understand PERFECTLY why you are
    excluded from instituting plus prevention.

    But to clarify that issue, here are some remarks
    by Judy on that subject:


    Dear Second-opinion Scientists,

    Subject: When YOU are responsible.

    I do not use the term Natural Vision Improvement -- because
    that implies that you need some "third party" to check

    I DO use the term "Natural Vision Clearing", because
    I intende that you:

    1. Read your Snellen, and confirm the Snellen
    line that you read.

    2. You understand the explict and legal requirement
    of Visual Acuity stated by the DMV in almost all
    states. And that is 20/40, which means EXACTLY
    that you read, at 20 feet, 3/4 inch letters.

    Thus if you confirm your Snellen at 20/60 (let us
    say), and confirm that a -1 diopter lens clears
    the 20/20 line, then your refractive STATE is -1 diopter.

    If you work with these PREVENTIVE methods (Bates,
    the plus, or BOTH), and working with your
    IVAC Snellen, you confirm you cleared the
    20/40 line, then you would pass the state

    These are actions you can take care of personally.

    Once all medical issues are cleared off the
    table, it then becomes a matter of having
    the motivation to do this work in a persistent
    and consistent manner.

    If you are successful (as per the above), and
    pass the DMV level test, then you simply
    do not need the involvement of a "medical" person
    at all.

    (But the involvement of a STRONG plus-prevention
    professional like Steve Leung would be
    advised.) See:

    Here are the reasons why Dr. Judy can not
    recommend preventive measures -- for your interest.


    Re: Do All doctors think EXACTLY the same way?

    Otis> And, by the way, I advocate that you always
    have periodic exams. What I suggest it that
    after the exam, (an the eye at 20/50 -- with
    the possibility of self-clearing) that these
    methods be discussed. It would be very easy
    for an OD to say, "... you have 20/50. You
    are in high school, and we know that the
    eye goes "down" at -1/2 diopter per year. If you
    wish to prevent, or clear, then click on
    i-see and explore the concept and suggestions.
    If you can clear your Snellen to PASS the
    DMV requirement, then that will prevent
    the development of stair-case myopia for you.

    Majority-opinion OD Judy says:

    Judy> Please do not complain about doctors not recommending NVI or
    suggest that it would be easy for them to do so. As I have pointed out
    before to you, it is not so easy. Licensed professionals have a
    fiduciary duty to their patients; they must be careful to provide
    advice that is in accordance with generally accepted standards of
    practice and which is backed by published science.

    [This depends on EXACTLY what you mean by science
    as it concerns the dynamic nature of the fundamental eye.
    I agree that YOU can never help a person with prevention -- and
    the person will simply have to figure it out for himself.
    I also ACCEPT that you remove yourself from this issue
    by your reasons. OSB]

    Judy> When there are published controlled human clinical trials of
    methods of vision improvement such as plus lens therapy, cognitive
    accupuncture, the Myopter, Bates exercises, supplements, herbals,
    massage, ayurvedic treatment showing that they are safe and
    effective, then ODs will recommend them. Until then, they won't.

    [Fine -- with me. Then again, the person must look at all of this, and
    accept YOUR determination that you can not help anyone with plus-
    PREVENTION, because it depends, not on you, but the insights of the
    person himself. If he clears his Snellen (refractive STATE moves
    positive), and passes, the Snellen, then there is no need for your
    involvement at all. This is of course what
    Dr. Colgate understood and did. But he was a very intelligent
    scientist -- and knew the optics and behavior of the
    natural eye. OSB]

    Judy> This forum (i-see) functions very well for people to exchange
    their opinions and experiences but don't expect doctors to recommend

    [I certainly do not expect you to recommend a course of action that
    requires that the person himself make this type of choice. That does
    a matter of the person choosing for himself the plus-preventive method
    -- of which you will never have any involvement with -- for obvious
    reasons. OSB]

    Judy> A doctor's recommendation carries a weight of approval of and
    agreement with content and cannot be done with an open content forum
    like I-see.

    [And to explain these issues in an office in five minutes would be
    impossible. I think this DEFINES the issue of individual empowerment,
    where the person make a choice of controling his refractive STATE
    himself. And that is an issue of science as the person understand it.

    Just one man's opinion.



    otisbrown, Jul 22, 2007
  17. DarkProtoman

    Neil Brooks Guest

    Nice straw man argument there, too, Uncle Otie. Was that one a result
    of too MUCH librium or too little?

    I asked the State of Pennsylvania to investigate YOU and only YOU. You
    were practicing medicine without a license. You really still are.
    They're just waiting for sworn statements from a few of your victims
    to prosecute.

    Since you're pathological, you'll provide more victims ... eventually.
    It's a statistical certainty.
    You COULD continue lying about Mike's position, but I'VE seen him SAY,
    repeatedly, that IF IT WORKED, he'd use it, so ....

    You're a liar, as always.

    Are you pathologically incapable of telling the truth??
    Neil Brooks, Jul 22, 2007
  18. DarkProtoman

    Dr Judy Guest


    So first Otis says:

    "What I suggest it that after the exam, (an the eye at 20/50 -- with
    the possibility of self-clearing) that these methods be discussed. It
    would be very easy for an OD to say, "... you have 20/50. You are in
    high school, and we know that the eye goes "down" at -1/2 diopter per
    year. If you
    wish to prevent, or clear, then click on i-see and explore the concept
    and suggestions"

    Then, after I explain to him, yet again, why doctors can't do this he

    " I certainly do not expect you to recommend a course of action that
    requires that the person himself make this type of choice. That does
    become a matter of the person choosing for himself the plus-preventive

    So Otis, are you finally convinced that doctors cannot recommend "plus
    prevention"? Will you now stop posting comments insisting that, in
    your opinion, doctors should tell their myopic patients about the
    various unproven therapies? Can we hold you to your last comment?

    Dr Judy
    Dr Judy, Jul 22, 2007
  19. DarkProtoman

    Ms.Brainy Guest

    How can you say that, Otis? Is my bionic eye no longer natural? Is
    it not fundamental? And above all, is it not dynamic? Besides, what
    about my other eye?

    But no, you rush to exclude me in a rather discriminatory way, while
    my myopia is clearing up rapidly as I continue to laugh. This is not
    fair, Otis. My dynamic bionic eye changes its fundamental STATE by
    applying pressure on the eyeball when I laugh so much.

    You owe me an apology, Otis. I am serious about it, even when I am
    sarcastic as some say without any scientific evidence.
    Ms.Brainy, Jul 22, 2007
    Kisame Hoshigaki, Jul 22, 2007
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