Posted by Larry Hoover on May 2, 2005, at 12:03:13
In reply to Re: Morontin.....anybody using it? (gabapentin) » Larry Hoover, posted by ed_uk on May 2, 2005, at 11:15:29
> Hi Lar,
>
> It looks like you're gonna need to get a prescription for the 100mg capsules.Ya, looks like it. I pretty much had concluded that already. I'm going to have to use this stuff almost PRN. I use the opiate PRN, but absent the gabapentin, PRN still led to routine daily use.....as needed can still be pretty consistent over time.
> Quite a few visual disturbances have been reported with gabapentin in the UK.........
Ya.
> Click on gabapentin at this website........
>
> http://www.yellowcard.gov.uk/daps.htmlThanks very much. That is a very useful summary. Weight gain, noted. Sheesh.
Re: visual disturbance. I had a visual field disturbance, and there is not one single case noted. There was, however, a fairly frequently reported symptom, hallucination. If one is to be pedantic (and I can be), I'd suspect that a goodly number of those hallucinations have been misreported.
<pedantic mode on>
Vision is processed in three concentric fields. In the center, you've got foveal vision. You use that for reading, as an example. It doesn't even cover whole words, despite your brain's ability to make you think that it does. Surrounding foveal vision is macular vision....these together are sometimes called the central visual field, or central vision. That's where you store and process all the detail....things like recognizing faces, and so on. As you're reading, the macular vision retains the beginning of the word, while you read the next individual letter groupings with the foveal field, for example. The processing is so seemless, you don't even know how much eye movement is involved during reading. (Saccades....yet another potential realm of visual disturbance.)
Outside the central field is peripheral vision, which really is only sensitive to changes. Light intensity, colour change, movement....those register in peripheral processing. In low light intensities, you lose central vision altogether. Night vision is peripheral vision (in effect), with very low central sensitivity. That's why we need flashlights/streetlights at night. Depth perception is a central field function, exclusively.
The amazing thing about the brain's processing of visual data is that it blends the fields seemlessly. You have no idea that vision is processed in three separate streams, and integrated after the fact.
Hold your finger in front of one eye, to block out a part of the computer screen. If you look only with the blocked eye (just close the other), there is a lot of data missing from the computer screen behind. Open the other eye, and look past the finger to the screen, and the blocked information is pasted in behind your finger.....it almost disappears. Your brain does that, all the time. Missing details are filled in. What exactly gets pasted into the visual gaps is a matter of some intellectual interest. Differences in eye-witness accounts? You can't verify detail from visual memories, despite our legal reliance on that. Your brain does not record pasting events. Visual memories are probably rewritten with each recall. But I digress.
Central vision data is pasted into the peripheral field, too, to blend the edges. The peripheral field takes on some of the characteristics of the central field, towards the boundary, to promote that blending effect. That accounts for the accentuated ring of disturbance that I reported.
Anyway, I had a peripheral visual field disturbance, which could have been interpreted as an hallucination. I know better than to call it that, though. I didn't see something that wasn't there, a definitional requirement for the term hallucination. I saw true visual data, in an impaired way.
<pedantic mode off>
I wonder if my reinterpretation of the reports of hallucination is valid.
> (sorry about the lack of detail)
>
> Regards,
> Ed.Thanks very much for the link. It's exactly what I needed to see.
Lar
poster:Larry Hoover
thread:492394
URL: http://www.dr-bob.org/babble/20050428/msgs/492649.html