Is it possible to divert light to a different part of my eye?

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Offline thedoc

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Paul asked the Naked Scientists:
   Hi Chris,
I now have had cataract ops for both eyes and 2 macular hole ops on my left eye because the 1st one failed. I now have a pair of reading glasses and progressives for general use, but it is still very unsatisfactory because I still have smudges in my sight and missing letters e.g. seeing "Go.d" instead of "Good".
I realise it is because I have missing rods at the back of my eye.
Is it possible to divert light so that it shines on a portion of my eye which is still okay with rods? Would that mean operating of shifting the connection with the optical nerve or might it be possible for me to mentally shift to regard the new point of contact of the light at the back of my eye to be the one to regard as central now? I presume it means making a special lens to divert the light to the right part of the eye,
This is just my idea. I haven't really researched it much but have I explained it to you to make sense? I have recently retired June 2016 and I have a private library of books to read and it is frustrating to have to concentrate on each word until I can see it clearly. On second thoughts, I suppose that is what I am doing now with my progressive lenses.
What do you think?
« Last Edit: 05/09/2016 11:53:01 by _system »


Offline evan_au

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There have been experiments such as you suggest that were conducted in the 1800s, and people adapted fairly quickly.

There have been more extreme experiments with prism glasses that inverted the whole scene, or rotated teh scene by 45 degrees. It was found that people were totally confused for a few days, and they started to get flashes of "right" vision after 4 days. This came about by rewiring the brain, rather than moving the retina.

In your case, a less extreme shift may move the image on the retina - but you would instinctively position the book so the image lands on (what used to be) the highest resolution part of your macula.

Unfortunately, you now have some gaps in this part of your macula. If you can locate these gaps, you could try to consciously read using a different part of your macula - but it will take continual concentration until it becomes natural.

It's really not what you wanted, but you can get quite good electronic book readers now - and eBooks.


Offline alancalverd

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Whilst diverting lenses or prisms might provide a quick resolution to the problem, it may not be optimal for all distances and applications - I doubt, for instance, if you would be allowed to drive with or without the spectacles and the world could look very disturbed if you removed them or woke up without them.

Having missing bits of retina is fairly common and AFAIK the general remedy, if it only affects one eye, is to live with it - the brain will learn to give dominance to the other eye when required. My father had a missing "stripe", probably from birth,  which disqualified him from professional flying (I have uniocular friends who fly privately) but by the time it was discovered at the age of 20 (RAF wartime selection board) he was unaware of it and perfectly able to drive, study, and play ball sports to a reasonable level.   
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