Protective Equipment
Laser Protective Eyewear
Plastic - Versus - Glass
The concern of plastic versus glass must be considered. This is essentially
the question of determining the conditions in which the eyewear is to be used.
Namely, is the user to be located in an area where the exposure could exceed the
damage threshold (PTL) of the eyewear or is it to be used by ancillary personnel
typically at a sufficient distance from the beam interaction site that the PTL
requirement is lower.
Obviously cost can play a major role. Laser protective eyewear is not inexpensive.
Units can range from about $90.00 for some plastic "goggle" units to over $500.00
for some special coated glass units. Many laser medical facilities purchase a
"mix" of units. It should be stressed that the choice of which eyewear to provide
should not be based only upon the cost but upon the Protection Requirement of
the individual considering the possibilities for worst case exposure.
The more laser resistant units are normally provided to those regular laser
personnel who work close to the beam and the less laser resistant are supplied
to those who normally work at a distance from the interaction site. Laser service
personnel are usually supplied the more laser resistant eye protection since their
activity will bring them in regular close proximity with the beam.
The final choice in the selection process will be the choice in filter types.
In some instances there will be a number of possibilities available. In these
cases, factors such as room light transmission (luminous transmission) may be
the deciding factor. Obviously the higher the luminous transmission the better
one can see to do the task.
Many times the final choice will be a trade off between all of the above factors.
One may be willing to accept lower luminous transmission but purchase a less expensive
eye protector while maintaining the required optical density level. It should
go without saying that one should never choose a filter with an inadequate OD
rating but one could choose a filter with less white light transmission and have
a functional protector.
