Protective Equipment
Laser Protective Eyewear
Selecting Laser Eyewear
All personnel using Class IIIB and Class IV lasers, whether in the production
facility, research lab, out-patient clinic or surgical environment, must be informed
to make the correct and optimum choice of laser protective eyewear. This means,
in general, the need for a more complete understanding of such topics as:
- The specific wavelength(s) of the laser emission.
- Exposure time of anticipated or "worst case" exposure.
- The output parameters of the laser(s) in use. This includes the average laser
power or pulse energy, pulse lengths, and pulse repetition characteristics (if
applicable).
- Worst case ocular exposure levels - either irradiance (W/cm(2)) or radiant
exposure (J/cm(2)) of the laser beam.
- The "safe" exposure criteria or Maximum Permissible Exposure (MPE) for each
laser.
- In some cases, aspects of the viewing condition (e.g. point source or extended
source).
- Reflection factors from targets at the laser wavelength. . Optical density
(OD) of eyewear at laser output wavelength based above factors.
- Visible light transmission requirements.
- Radiant exposure or irradiance at which laser safety eyewear damage occurs.
- Need for prescription glasses. . Comfort and fit. . Degradation of absorbing
media.
- Strength of materials (resistance to shock).
- Need for peripheral vision.
- Specifications of the protective devices commercially available.
It should be stressed that laser hazards can also include hazards associated
with electrical power supplies, flammable or toxic chemicals and materials, fuel
hazards, respiratory hazards from laser induced fumes and vapors, and noise hazards.
These factors should also be considered in selection of protective equipment;
especially eyewear. These conditions may result in hazards from laser related
operation (flash tubes, chemicals, fumes, etc.). Consult ANSI Z-87.1: The American
National Standard Practice for Occupational and Educational Eye and Face Protection,
as-well-as ANSI Z136.1.
