double image through eyeglass

Discussion in 'Glasses' started by ns666ns, Nov 9, 2006.

  1. ns666ns

    ns666ns Guest

    Hi, I got my new pair of eyeglasses, but my left eye see double images
    slightly off each other. for example, look at 2 neon horizontal line
    lights (one about 1 inch above the other) especially in green color,
    from a distance about 15feet, my left eye through eyeglasses will see
    "3" lines of neon lights, the "ghost image" is higher than the 2 real
    image, if I raise my head backward such that I see the neon lights
    through lower part of my eyeglasses, the "ghost image" will disappear
    and I see clearly. if I walk closer to about a few feet, double image
    will disappear, this is left eye only, same with and without my right
    eye open.

    I wonder is this due to the not so good prescription of the eyeglasses?
    what could cause such problem from eyeglasses optically? or is it my
    left eye that's the cause? (I can't tell since if I look at things with
    naked left eye everything so burry hard to tell if there's a slightly
    offset ghost image) another pair of glasses with similar prescription
    except axis 8 degrees different has the same problem.

    thanks a lot!
     
    ns666ns, Nov 9, 2006
    #1
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  2. ghost images as you describe are pretty normal, esp. from strong
    emitters like fluor. tubes. The blur is not normal, and means something
    is wrong with your eye or the lens. AR coating will help minimize
    ghosting. Since the ghosts merge with the main image in the lower part,
    that means your lens might also have some unwanted vertical prism.
    Removing the prism will help the ghosts merge closer to the part of the
    lens you mostly use (usually a bit above center).

    w.stacy, o.d.
     
    William Stacy, Nov 9, 2006
    #2
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  3. ns666ns

    ns666ns Guest

    thanks for the reply,

    the "ghost" image I don't mean the ghost image caused by multiple
    reflection on the lens surface which as you said can be reduced by AR
    coding, I see those but those are lower than the real image and pretty
    far apart, the ghost image I mentioned is just slightly (like shadow)
    above the real image which I can't understand the mechanism by light
    tracing through the lens. the "unwanted vertical prism" sounds
    interesting but this zeiss lens is made with prescription for
    nearsightness only without any "prism" spec, do you mean they can make
    different lens while maintain the same prescription?
     
    ns666ns, Nov 10, 2006
    #3
  4. ns666ns

    Charles Guest

    I'm no eye doc, but this sounds similar to how my astigmatism manifests
    itself uncorrected. Rather than smearing, I get fairly distinct
    doubling. Maybe your prescription isn't fully correcting.



    --
     
    Charles, Nov 11, 2006
    #4
  5. ns666ns

    ns666ns Guest

    I found the official name for this: Monocular diplopia, the question
    is, is it caused by my eyeglass or my eye itself? if it's my eye, I
    would imagine I will see the same double when looking through lower
    half of my eyeglass, but no double in that case...
     
    ns666ns, Nov 11, 2006
    #5
  6. I meant "I'm not convinced that your original post was incorrect".

    Tripped up by the double negative once again...

    w.stacy, o.d.
     
    William Stacy, Nov 13, 2006
    #6
  7. My confusing reply was made worse by my attempted correction. Here, let
    me fix it one more time:


    oh and yes, they can grind prism independently of the spherocylindrical
    Rx, and it can be as ordered (prescribed) or accidental (inadvertent).
    If it's enough, you can get binocular diplopia and other binocularity
    symptoms from it.
     
    William Stacy, Nov 13, 2006
    #7
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