Re: Those who cannot see or enjoy stereo

[P3D Gregory J. Wageman <gjw@xxxxxxxxxx>]

Dr. T. observes:

>One young fellow left in the middle of the
>presentation.  Later he told me that he was getting a
>headache.  I have heard this in the past.  Others have reported
>similar reactions.  Clearly, there are no misalignments in my
>projected images.  Then why are some people reporting such
>reactions?

I'll throw my 2 cents into the stew (add metaphor; mix thoroughly).

At NSA '97 I noticed that after long periods in the Stereo Theatre, my
*neck muscles* were becoming sore.  I commented on this to Susan, and she
said that hers were also.  My theory is that because one must hold one's
head almost perfectly vertical for long periods, one doesn't do the usual,
unconscious head tilts and movements which normally prevent muscle tension.
I further theorize that in some people, this leads to headaches (or
possibly, the muscle tension is mistaken for, or misreported as, a
"headache").

One possible way to obtain evidence to support or discredit this theory
would be to check with long-term users of LC shutter glasses, to see if
they also report headaches.  Of course LCS users have a (hopefully) high-
frequency flicker to contend with that slide viewers don't, but on the
other hand the LCS glasses allow head movement without losing the stereo
effect.

Use of circular rather than linear polarization should be better in this
regard.  I wonder if any studies have been done...?

	-Greg W.


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