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Further visual problems

I posted recently about eye problems I was having, which were down to ON.

I am also experiencing 2 further very odd symptoms, and again I'm not sure if these are ON or even MS related. One is "macropsia", where objects "feel" larger than they are in my minds eye. The second is a loss of visual memory - when I try to visualise, for instance, something simple like a "green apple", I cannot bring the image together in my consciousness despite of course knowing what a green apple is.

Any ideas? Is this a wholly different field of neurology here?!

Sorry, I can't be of any help but my wife is an Optometrist and she 'may be' able to help?

Visual imagery uses exactly the same brain areas as proper vision. (This was the original topic for my PhD so I have read extensively on this topic!)

The information from the eyes goes via the optic nerves to the lateral geniculate nucleus of the thalamus, deep in the brain, and then onto the visual cortex (also known as the occipital cortex) which is right at the back of the brain. From there, the information feeds forward to lots of parts of the brain, initially through the temporal and parietal lobes. Visual information relating to objects (e.g. colour and shape) is processed in the occipital and temporal lobes. Information relating to actions (e.g. how far away something that you want to reach for is) is processed in the occipital and parietal lobes.

If you are not having any difficulty with reaching and grasping or other visually guided actions then I would guess that you have something going wrong in the occipital-temporal pathway (also known as the ventral pathway of vision): an MRI might show a new lesion along that route, I would guess in the early part of the temporal lobe.

The fact that you have lost your ability to do visual imagery is actually fascinating for anyone studying visual imagery! I wish I was still researching - I'd have you in the scanner in a shot!!!

Unfortunately, I can't think of any treatment for it - sorry. Hopefully time will do the trick - practice might be a good idea too - teaching the brain how to do it again. It can work!

Karen x

That's really interesting, thank you so much for such a considered reply. I wondered if I had a new lesion - I'm trying to see a nuero-opthamologist to see if they can shed any light on it. I'm not having any trouble with locating objects in space, just (just!) the very odd macropsia (much more troublesome when my eyes are closed, so when not receiving any visual stimuli), and the visual imagery (which is intermittent).

Hey ho! I'll see what happens, thanks to everyone for their replies.

Sarah

Hi,

My first bout of ON was in '97 and I remember that during that time,I was once on a train journey.During this journey,I was alarmed to notice that,looking out the window,a lot of objects were disproportionately large.It was very weird.It only happened this one time and I never thought to say anything to a neurologist.I might mention this to my neuro.

Can't help you otherwise,but I hope that it clears up soon.Take care,Brenda x