UV exposure (was: EtBr safety procedures)

[Paul N Hengen]

pnh at fcs260c2.ncifcrf.gov (Paul N Hengen) writes:

>>>>How dangerous is it to have your light source briefly being exposed
>>>>to the naked eyes of passersby?

>>The glance will probably not expose you any more than a full day at the
>>beach with your eyes closed,

mbrgw at s-crim1.dl.ac.uk (R.G. Walters) writes:
 
>Not true. The levels of 254nm (the most damaging) UV at ground level (even
>with ozone depletion) are virtually undetectable.  Transilluminators are
>VERY strong sources, and even at a distance of several feet are not something
>I would want to be in the way of, let alone be looking at.  

Robin: Since you know quite a bit about this, I'll ask you my questions...

1. Is 254nm UV detectable by the same procedure at say 10-15 feet from
   a shortwave transilluminator?

2. How much exposure would you expect for say 3 seconds?

3. Is the same level detectable from the mid-range (300nm) or longwave (366nm)
   transilluminator at this distance?

4. What damage is done to the cornea at this level?

5. What is the source of the "sandy-eye" feeling from mild UV exposure?

Paul N. Hengen
National Cancer Institute
Frederick Cancer Research and Development Center
Frederick, Maryland 21702-1201 USA