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The Tested Demonstrations Editor replies to Ibanez:
The concerns expressed by Jorge G. Ibanez are real, according to an apparently
authoritative and very informative essay, “Safety Recommendations of Laser
Pointers” by R. J. Rockwell, Jr., W. J. Ertle, and C. Eugene Moss, available
on the Web (1). This article notes that Class IIIA
laser pointers are available in the U.S., even though they are banned in the UK.
These lasers may be hazardous even if viewed for a very short time, and little
research has been done on the chronic exposures like those reported by Ibanez.
Lasers are classified from I (least dangerous) to IV, which requires strict control
measures. Up to class II are allowed as laser pointers in the UK. According to
the Laser Institute of America cited by Metrologic (2),
a Class II laser is defined as follows:
A Class II laser or laser system must emit a visible laser beam. Because of
its brightness, Class II laser light will be too dazzling to stare into for extended
periods. Momentary viewing is not considered hazardous since the upper radiant
power limit on this type of device is less than the MPE (Maximum Permissible Exposure)
for momentary exposure of 0.25 second or less. Intentional extended viewing, however,
is considered hazardous.
Literature Cited
- Rockwell
Laser Industries: Safety Recommendations. (accessed Oct 2002).
- Metrologic
Instruments Inc.,Technical FAQs (accessed Oct 2002).
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