Double vision

[geoffito123]

Hello everyone, this is my first post.

I've been diagnosed with keratoconus for a few years now. Over the last year I've been trying different hard contact lenses. It has been relatively successful as I notice a definite improvement in vision, especially when reading and looking at faces. I study Chinese, which obviously requires sharpness when reading.

However, despite sharpness with the lenses, I have a problem with double vision. Images, especially words and lights are doubled and hover above the actual image. This is a problem without the lenses but persists with all the lenses I've tried.

Does anyone else suffer from this and if so, could you offer some advice.
Also, can anyone recommend a specialist in or around London?

Thanks in advance,

Geoff

[GarethB]

Hi Geoff

Welcome to the forum.

I have what you descibe regarding words hovering about. For me this was diagnosed as dyslexia and having a slightly different tint to each lens has made the difference. The words no longer float about, just shimmer slightly and the dyslexia is not as bad.

[StuUK]

Hi Geoff

I suffer from the same problem. Without lenses in I get ghosted vision which causes lights to streak in a kind of oval down from the ligh source. This also happens when reading and words seem to overlap each other.

I have been trying out contact lenses and with the RGP ones I have I experience the same problem in that they bring the remaining ghosted image in to focus (down from about 10) so that images float over the top of each other and are more opaque than without the lens in. The strangest experience I have had with this is when being driven, if I look at a number plate one image is ghosted and the other is in focus, as I get closer to the number place the two images flip so they are the other way around, this is very disorientating.

I have a pair of glasses which move the ghosting around and makes it less opaque such that it causes less problems as words do not overlap and light sources streak straight down so are not so much a problem except for at night (cannot drive at night at all). I don't know whether this would work for you but could be worth a try.

I am currently trying different lenses to try and remove the final ghosted image but its proving frustrating for both me and the fitter at the moment! Really good vision in the fitting room but then ghosting hell once I get outside.

Hope this helps

Stuart

[Lynn White]

Okay.. we are talking two different types of ghosting here I think.

People with KC often get ghosting as its caused by the distortion in the optics of the eye. Although contacts can remove this to a certain extent, they cannot entirely as the optics of contacts and specs deal mainly with "normal" aberrations in the optical system and doubling and ghosting is caused by "higher order" aberrations, such as coma. Sorry to get technical but this is actually what it is!!

This is why intacs can "work" even though they don't appear to "improve" things prescription wise, They help to reduce the effect of these higher order aberrations by pulling or pushing the cone into a better shape so you get less ghosting. This was talked about at the recent conference and you will be able to see what was said from the DVD when It comes out.

Now what Gareth is talking about is that some dyslexics suffer doubling of letters and do quite often benefit from coloured lenses, often for one eye only.

The visual system can be quite complicated!!

LYnn

[Pat A]

Lynn
Sorry for being thick - but what do you mean by "Coma" in this context? It was mentioned at conference too but I didn't pick up on the meaning - can't see that you mean unconsciousness which is what coma is generally..

Thanks

[Lynn White]

Hehe... I was afraid you might ask!

It is hard to explain in non technical terms, but let me try....

If light from an object enters your eye "on axis" ie along the line perpendicular to your eye, its not really disturbed by any distortions in your optics. However, if light enters your eye at an angle ("off axis"), some will pas through the optical centre of your eye and some light will pass through peripheral areas. The light gets bent differently in each case and can end up giving you multiple images, especially if you have a large pupil because light going through the middle of your pupil will be affected differently than light passing through the edge of your pupil.

Look at this link here... http://en.wikipedia.org/wiki/Coma_%28optics%29

again its a bit techo but you can look at the diagrams.

If you have a cone that is displaced from the centre then you can see that light passing through the cone will be bent (ie refracted) differently than light NOT passing through the cone.

Its a hard fact of life that people with KC run into problems optically that are usually only dealt with in physical optics labs in relation to optical instruments. It is this that makes fitting contact lenses so challenging!

Get straight back to me if you want things explaining more!

Lynn

[Pat A]

Lynn
Thanks - and actually that's really helpful - especially the diagrams! I always prefer pictures to words - (especially since I've developed my KC & cataracts and can't read very well!!)

[rosemary johnson]

Hi, and welcome.
Yes, I get multiple ghost images too.
One main image, then several faitner ones.
WIth my elft eye, the llens more or less takes the multiples out - there is one main image, and if I look carefully, one fainter one vertically above it. Tipping my head back slightly and looking slightly down at things helps, as does (oooh! horror!) screwing myeye up slightly, which effectivey removes it).
WIth my right eye, I get lots of ghost images - one main one, and several more, in different directions, in varying degrees of faintness compared to the main image.
Read with my right eye takes a LOT!!! of concentrationa nd is pathetically slow, because of all the ghost images.
I once tried to draw what I could see on my computer screen, from having a single "o" on its own inthe middle of a dark area (I have light letters and black achground). I think there were 7 of them.

What to do about it? - in my earlier years with the elnses, we (me and my then-practitioner) discovered that I got better vision if there was less of a central clearance zone and the lens was closer to the cornea - these were sclerals I'm talking about here; I've always worn sclerals and not the corneal lenses.
What's more, the closer fit was ore comfortable - because I wasn't screwing myeyes up so much to try and make the multiple images go away.
Practitioner reconed I was going against every text book ever written.

I remember one of the speakers at the conference saying they'd sometimes meet a new patient, take one look and thnk their previous practitioner must have been crazy, as their lens fit looked so awful! I rather suspect that when I first went to Moorfields, I must have been put in that category. ANd it took .... oooh, how manyyears was it now??!!! - for them to come round to the conclusion that, it may go against every text book ever written, but the previous guy knew what he was doing because it seemed to work.

Of course, in those long-ago days (!), all the lenses were made out of PMMA (brand name Perspex). Now they are made out of one of the range of Rigid Gas Permeable (RGP) plastics, and the trade off between comfort, fit and vision is very different with PMMA and RGP materials. uge great central contact zones that did fine for me in PMMA give awful problems of comfort in RGP. Hence the piggybacking....... which does great things for the comfort, but still leaves lost of multiple ghost images.
One street light looks like a whole Christmas tree - and that from the far side of the car park. Hey ho.
Rosemary

[John Smith]

Of course, Dan Erlich at the conference also made the point that just because a lens is comfortable doesn't mean that it's good for you. It could be damaging your eye much more than an uncomfortable lens!