2 pair vs. progressives

Discussion in 'Optometry Archives' started by kecctime, Mar 3, 2006.

  1. kecctime

    kecctime Guest

    First, a question about my prescription. It is distance: -2.25 left and
    right, Reading +2.00 left and right. Is this prescription for a single
    vision lens with curvature that varies or is it for a bifocal? Second,
    I've tried progressives before and had difficulty with them - couldn't
    stand moving my head so much. I'm at a computer for many hours each
    day. Would a pair of single vision glasses for distance and a lined
    bifocal for reading/computer work? Could a bifocal be made for reading
    and intermediate ranges and would that be effective for working at my
    PC/desk? Thanks.
     
    kecctime, Mar 3, 2006
    #1
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  2. kecctime

    CatmanX Guest

    Ever thought of talking to your optometrist, it is his job you know.

    If he won't discuss it, you are at the wrong place and look for
    another.

    For what it's worth, this script won't work on a computer, bifocals
    will give you a sore neck and you will whinge here about how you hate
    bifocals and how horrible your glasses are.

    You can try some of the new generation MF's like Ipseo, SolaOne HD, or
    the like, get an intermediate script made or whatever else you like,
    but it would help if you got a good optom to test you and give you your
    options with you in presence.

    dr grant
     
    CatmanX, Mar 3, 2006
    #2
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  3. kecctime

    Quick Guest

    I guess this is on topic for this thread...

    How does a progressive "progress"? I'm assuming
    there is some sort of seg height where the lens power
    starts to diverge from the distance Rx and starts
    to move towards the add. I assume it hits the add
    power somewhere before the bottom of the lens
    (assuming the lens is large enough?). ...that brings
    up a second part of the question.

    First, not considering lens size, is the rate of change
    in power constant from the distance Rx to the Add?
    Or are there transition zones and segment areas?

    Is this variable dependent on lens height?
    Can all the above be specified? Could I design my
    progressive lens to have 3 sort of segment areas
    where the rate of change in power over the segment
    area is small relative to the transition zones.

    This is what I would expect a "no line tri/bifocal" to
    be. Naturally I have something in mind... A "progressive"
    trifocal with maybe 1/2 the lens distance, 1/3 computer
    and 1/6 near.

    -Quick
     
    Quick, Mar 3, 2006
    #3
  4. kecctime

    CatmanX Guest

    Sorry, Mike, but I will qualify some of what you have said, well,
    semantic little bits anyway.



    Most lens designs these days have a more rapid shift in the first (top)
    half. A Varilux Comfort lens (older design, but I remember the figures
    as it was the first of its kind) reached 85% of the near add at 50% of
    the corridor. The purpose is to get quicker to the reading zone without
    the head tilt.


    Yes, but remember Quick, that different designs have different corridor
    lengths and different shift characteristics which are dependant on the
    manufacturer and what they want to achieve.



    This is the good thing about having so many designs on the market. You
    effectively do this by selecting a design. Some perform better for
    intermediate, some for distance and others near.

    Well stated Mike. The thing to remember Quick is that we are getting
    much better at MF design and the flexibility of newer designs is so
    much better than before. What you want is probably going to be easily
    achieved with the latest generation of lenses such as Ipseo, Hoya ID,
    Sola HD etc. By incorporating the multifocal on the back surface, you
    get less peripheral swing, wider reading and intermediate zones and
    better distance clarity.

    dr grant
     
    CatmanX, Mar 3, 2006
    #4
  5. kecctime

    Quick Guest

    Drat... better call my doc and put a hold on the order or
    talk to him about it. (and I left my script at home...). Now
    that I'm finally very happily fitted with my translating trifocal
    RGPs I figured I might as well get a pair of progressives as
    a backup. I hadn't planned to and figured I could make do
    with my drug store readers in a pinch but at the last moment
    figured what the hey, might as well. Being the ultimate
    consumer and sort of an impulse buyer it only took about
    15 minutes to gravitate towards the Lindberg Air Titanium
    frames, grey transition progressive lenses, with Zeiss(sp?)
    gold (I understand that's better for night issues where the
    blue is better for daytime issues) AR. Doc recommended
    polycarb for my weak Rx and didn't know if the transitions
    came in trivex. Apparently they don't. He said plain CR39?
    plastic would be fine as well but he didn't like it because of
    no UV protection. I thought *any* plastic provided UV protection?
    I think my script is something like 0.75 with a 2.25 add and
    very slight astigmatism in the left eye. He did show me the
    trivex display where they have a special light that shows the
    trivex lens clear next to the polycarb that looks like a rainbow
    resulting from oil on water but said he didn't think it would
    make a difference with my script. I'm pretty discerning
    (perfectionist/anal) about everything and figured "trivex for
    me!). besides I felt like throwing as much business his way
    as possible sort of as thanks for the tremendous effort he
    put in working with me on the trifocals.

    thoughts?

    -Quick
     
    Quick, Mar 3, 2006
    #5
  6. kecctime

    Mark A Guest

    Your Rx is for bifocals or progressives. It can also be used for SV lenses
    that are used at a distance (such as driving) and the add power will be
    ignored.

    Distance lenses are optimized for 20 feet, and add power (reading) is
    optimized for about 13 inches. Measure the distance from your glasses to
    your computer monitor. If it is more than about 17 inches, you might want to
    get a special pair of bifocals or SV lenses that are optimized for computer
    work at your working distance (and one other distance if you want bificals
    or progressives). Ask your OD to give you an Rx for your computer monitor
    distance.
     
    Mark A, Mar 3, 2006
    #6
  7. kecctime

    acemanvx Guest

    If you sit around a foot and a half from your computer monitor, you
    dont need glasses for that. If you sit a little further, you can just
    move up so your 18" away from the monitor. If you sit far, what you can
    do is get "computer glasses" a pair of reduced power glasses just for
    the computer. This is what I did, so much easier than bifocals or
    progressives for the computer!
    If you cant handle progressive or bifocal, theres no need really. You
    are mildly myopic and can simply peak under your glasses or remove them
    for reading
     
    acemanvx, Mar 4, 2006
    #7
  8. kecctime

    CatmanX Guest

    Shut up idiot. Why would he be asking about lenses if he wanted four
    pairs? Don't wear glasses and all will be well, as long as you don't
    want to sewe anything.

    dr grant
     
    CatmanX, Mar 4, 2006
    #8
  9. kecctime

    David Combs Guest

    Would you please explain WHY you'd get a sore neck?

    "Executive"-style BI-focals are actually a *good* solution
    to his problem, perhaps the *best* solution.

    Like, suppose he's got a 20" screen, and wants to
    point his nose at its center and then be able to
    flip his eyeballs up, down, left, right, and see
    everything super-sharp? Fron a distance of maybe
    24 inches.

    Just how can he (or you) do that via progressives.
    with their hourglass-shaped in-focus area?

    Just be careful to make sure both left and right
    eye, with the glasses on, come to exactly the SAME
    distance for perfect focus. If your accomodation
    has gone to about ZERO, as mine has, you'll
    have play with the balance between the two eyes,
    up to the most precise (one-quarter diopter, I think
    it is). Makes all the difference, having the
    left and right eye come to focus at EXACTLY
    the same distance.

    One thing for sure about pregressives: they cost a LOT more
    than bifocals, with the extra fitting, etc. Might that
    be *one* of the (several) reasons for optometry-shops
    recommending them?


    ?get an intermediate script made or whatever else you like,
    David
     
    David Combs, Mar 30, 2006
    #9
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