double image through eyeglass

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!

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.

(E-Mail Removed) wrote:

>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!
>
>
>

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?


William Stacy wrote:
> 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.
>
> (E-Mail Removed) wrote:
>
> >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!
> >
> >
> >

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.

(E-Mail Removed) wrote:

> 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!



--

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...

I meant "I'm not convinced that your original post was incorrect".

Tripped up by the double negative once again...

w.stacy, o.d.

My confusing reply was made worse by my attempted correction. Here, let
me fix it one more time:

William Stacy wrote:

> I'm not convinced that your original post was incorrect, and I do
> think that they are indeed probably ghost images, which are caused by
> internal reflections (light refracted through the front surface,
> reflected off the back surface back toward the front surface, then
> once again reflected back toward the eye off the front surface). You
> can differentiate these ghost images from other sorts of monocular
> diplopia by the fact that if the lens has any power at all, the
> separation between the primary image and the ghost image will change
> as you vary the part of the lens through which you are viewing,
> exactly as you described in the first post. No other kind of
> monocular diplopia behaves like that. Prism simply shifts the ghost
> image away from the base of the prism, but the separation will still
> change as you move your line of fixation. If on the other hand the
> lens has no refractive power, then the ghost will be on the main image
> (not visible to you), or displaced by the amount of prism, and will
> not vary as you use different parts of the lens.
>
> w.stacy, o.d.


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.