> 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.

> 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.
> > > ns666ns[at]yahoo.com 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!
> > > > > > > > > >

> 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.
> ns666ns[at]yahoo.com 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!
> >

> 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!