Which lens for improved off-axis optical quality for -8D w/ cyl?

Discussion in 'Optometry Archives' started by eekthorp, Jan 4, 2007.

  1. eekthorp

    eekthorp Guest

    This distortion/blur is somewhat noticeable at 20 and definitely 30
    degrees off-axis of OC. This means I cannot read small text across a
    17" screen without moving closer or moving my head back and forth.
    Similar with street signs, etc.

    It seems like eyewear-lens-oblique-astigmatism [1] (not
    eye-oblique-astigmatism [2]) may be the main part, but chromatic
    aberrations have a (secondary?) roll. I'm basing this off of my
    observations from reading white and black text and single-spectrum
    (red, yellow, green, or blue) text. [3]

    I can see *much* better out of my contacts since they move with the
    eyes, so I know what I'm missing when I'm using my glasses.

    My place will give me their 'standard' Hoya Nulux 1.6/1.67/1.7
    aspheric, or let me special order something else, if I request.

    Is their 'standard' great for my need, or could I do better by
    special ordering a different design/material?


    My Glasses
    * OS: -8.00D -0.5 75
    * OD: -6.75D -1.25 70
    * Frame: 47-17, lens height 20mm. OC/sweet spot is 30mm from center of
    bridge. Lens is close as possible to eye.
    * No-AR [I'm getting AR now, which should improve vision but
    shouldn't affect off-axis fuzziness, right?]
    * Spherical-cut toric-prescription polycarb.
    * Thickness (11mm edge) and weight is fine in
    * Would pay for thinner & lighter, if noticeable, but would also
    tolerate thicker & heavier if it's only way for noticeable optical

    Local eyecare professionals gave a "full spectrum" of responses
    "Highest index and asperhic upgrades will give sharpest on and off
    axis vision. Hoya Nulux 1.7 Aspheric."
    "Highest index will improve off-axis vision and aspheric has no
    practical off axis difference from spheric. Seiko 1.67 spheric"
    "Lower index spheric is best. High index OR aspheric will give off
    axis degradation."
    "Sola (ViZio) is for people needing progressive lenses and not
    applicable to you."
    "Practically, there's nothing you can do about off-axis distortion,
    so don't fret over it."

    Past newsgroup discussions recommend
    Spheric or Aspheric:
    * "Lowest index tolerable aesthetically, CR39, trivex, or most likely
    (high abbe) 1.6 with spheric. Aspheric is just a technique to reduce
    distortion caused by choosing a flatter base curve for aesthetic
    * Sola Spectralite 1.53 (ABBE 47) (spheric) [4]
    * Essilor Thin, Rodenstock & Zeiss [5]
    * Seiko's 1.67 & Silor's Thin and Light

    * Optima's Resolution poly (atoric)
    * Multigressiv atoric, possibly intended for progressive.
    * Sola ViZio 1.66 atoric, possibly for progressive.
    I noticed the Sola ViZio marketing promotes giving improved field of
    view, however Darryl's article uses an example astigmatism with a
    convenient 90deg cyl.. Is this specsmanship, or is the same improvement
    in field of view seen at 'real world' astigs which don't follow the
    horizontal lens axis (ie, 70-75 like I have?)? [6]

    Questions that can help me make an informed decision
    Which lens cut (spheric/aspheric/atoric), if any, improve
    lens-oblique-astigmatism over others?
    Which types of lens material (high/low index, high/low ABBE) improve
    In addition to ABBE, is high/low index or spheric/aspheric/atoric cut
    better for chromatic aberration?
    Is there a chart that discribes the tradeoffs of 'when' a certain
    combination makes sense?

    [1] http://www.laramyk.com/learn/aspherics_1.html
    [3] As an aside: I did some other rough calculations and experiments on
    the chromatic aberration. Maybe I'll post that tidbit after I figure
    out what lens to have made.
    [4] "Best Glasses: Abbe value and optics", 1999,
    [5] http://www.eyecarecontacts.com/thin_light_lenses.html
    eekthorp, Jan 4, 2007
    1. Advertisements

Ask a Question

Want to reply to this thread or ask your own question?

You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.