From: uselton@nas.nasa.gov (Samuel P. Uselton)
Subject: Re: VR hardware safety response
Date: Wed, 5 Jun 91 16:51:31 GMT
Organization: NAS Program, NASA Ames Research Center, Moffett Field, CA



In article <1991Jun5.031158.15999@milton.u.washington.edu> kilian@poplar.cray.com (Alan Kilian) writes:

>galt@hellgate.utah.edu (Greg Alt) Says:
>
>> It seems that CRT's are a possible health risk and should not be used 
>> right up against your eyes for a long time.
>
>That debate rages on and until I see some more articles I am not going
>to put any CRT based displays right in front of my eyes. The "Light valve"
>designs seem much safer in the mean time.

Just a quick comment on this discussion.  I don't claim to be a medical
expert OR to play one on TV, however, we (NASA Ames Research Center,
NAS Systems Division, Applied Research Branch) commissioned Mark Bolas
of Fake Space Labs to do some digging on this topic.  Bottom line:
Exactly what Alan says, IF you are discussing COLOR CRT's: no conclusive
results, lots of opinions, better wait until good studies are complete.
However, black & white CRT systems are MUCH lower voltage, lower radiation
and EM fields, etc, so no responsible eye researcher seems to claim terrible 
things about having them close to your face.  We are investigating ways of
putting color into our boom mounted viewing/tracking system.  Mark, Steve
Bryson and Creon Levit (our two main VR guys) seem to have a plan for at
least some color while still using B&W CRTs.  I'll wait until I see details
or a demo before I promulgate those rumors further.  If you really want to
know soon, ask them.

>
>                  -Alan Kilian
>
> -Alan Kilian kilian@cray.com                  612.683.5499
>  Cray Research, Inc.           | "The Fragile X Syndrome may me the most
>  655 F Lone Oak Drive          | frequent cause of inherited mental
>  Eagan  MN,     55121          | retardation". Science 24-May-1991 PP1097

Sam Uselton		uselton@nas.nasa.gov
employed by CSC		working for NASA (Ames)		speaking for myself