Brendan:
I read the response from John OHagan and Bill Davies and agree, but I
might add two things.
1) Perhaps it is not a big problem in the UK, but in many warm US
locations, lens fogging is a major cause of non-compliance when eye
protection is recommended. For that reason, we do not even recommend a
"tight fit." Of course 1 cm might be a bit wide!
2) The vulnerability of the eye from extreme angles to the optic axis is
low, so the gap is probably not as dangerous as some might expect. We even
had a case some years ago in the US where a laser worker received a macular
burn from a laser exposure that he said resulted from a beam entering this
gap from below. Of course this was ludicrous to anyone familiar with ocular
anatomy and physiology. In order for this exposure geometry to be true, the
eyeball would have had to come out of its "socket" and turn down nearly to
point at his feet.
Dave Sliney
================================================
David H. Sliney, Ph.D.
Manager, Laser/Optical Radiation Program
US Army Center for Health Promotion
and Preventive Medicine
ATTN: MCHB-TS-OLO (Bldg. E-1950)
Aberdeen Proving Ground, MD 21010-5422
USA
Phone: 1(410)436-3002
FAX: 1(410)436-5054
e-mail: [log in to unmask]
<mailto:[log in to unmask]>
-----Original Message-----
From: Tuohy, Brendan, UCHG [mailto:[log in to unmask]]
Sent: Tuesday, July 16, 2002 8:25 AM
To: [log in to unmask]
Subject: Laser safety glasses
Hi,
A pair of laser safety glasses manufactured by lasermet Ltd.(USA), have been
sent by a member of staff for my attention. They are concerned that there
is an opening between 0.5 and 1 cm, at the bottom of the glasses between the
frame and the contour of the face. Would you consider this to be a cause
for concern?
Thank you,
Brendan
___________________________________________________
Brendan Tuohy, Principal Physicist, Dept. of Medical Physics and
Bioengineering, University College Hospital, Newcastle Rd., Galway, Ireland
Tel: +353-91-544769/544770; Fax: +353-91-583017
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