Use of Laser Pointers

STATEMENT ON THE USE OF LASER POINTERS

Laser pointers have been used in lecture theatres for a number of years and when used in a responsible manner they can be an effective tool. Recently, due to price reductions, these devices have been marketed widely as novelty items and complaints have been received of their inappropriate use by some attendees during lectures.

Laser Hazards

Lasers, an acronym for Light Amplification by Stimulated Emission of Radiation are an extremely bright source of light. A 1 mW visible laser is about one million times more brilliant than a 100 watt light bulb and such light can, under certain conditions, cause damage to the eye. Lasers are classified into four main classes to identify the risk associated with them. Class 1 represents the least hazardous where exposure of the eye to direct or reflected beams is not expected to produce any damage. Class 2 lasers have an output of up to 1 mW and do not damage the eye when the exposure to the eye does not exceed 250 milliseconds. This is normally the time that it takes to react to a bright source of light and close one’s eye (the blink reflex). Class 3 lasers are subdivided into Class 3A (output < 5mW) and Class 3B (output > 5mW). Class 3 and 4 lasers can damage the eye in a time less than the blink reflex and because of this Class 3B and 4 lasers are subject to strict controls under the University’s laser safety program.

Class 1 lasers are not sufficiently bright to be of use as pointers and therefore laser pointers are Class 2 or Class 3A. The latter emit up to 5 milliwatts and they will produce exposures that can damage the eye faster than one can blink. The United Kingdom has banned the sale of Class 3A laser pointers although they are legal in Canada and the United States. A number of State and local governments in the U.S. have enacted regulations to limit the use of Class 3A pointers.

Exposure of a person’s eyes to a momentary sweep of a Class 2 or Class 3 laser beam can result in temporary flash blindness, afterimage and glare which can be particularly dangerous if the individual is engaged in a vision-critical activity. There are documented cases of retinal damage following multi-second exposures to Class 3A laser pointers.

Safety Precautions

  • Recognize that Class 2 and Class 3A laser pointers are not toys and that Class 3A lasers in particular can cause damage to the eye;
  • Only purchase pointers where the output power, laser hazard classification and a warning about potential eye hazard are shown on a label or included in the instructions for use;
  • Unless needed for a specific purpose, avoid the purchase of Class 3A laser pointers;
  • It is recommended that only pointers which have a maximum Class 2 labeling (less than 1 mW) be used with wavelength between 630 and 680 nm; purchase a shorter wavelength laser if given the choice: a 1 mW laser at 630 nm will appear much brighter than a 5 mW laser at 670 nm;
  • Never look directly into the laser beam;
  • Never aim the pointer at people or at reflective surfaces;
  • Only purchase pointers that stay on only while you apply pressure to it with your fingers;

Misuse

Improper use of a laser pointer by failing to follow the safety precautions can cause eye damage and such practice is not acceptable. Improper use may create conditions that endanger the health or safety of others, and includes disruption of classes through playful scanning of beams, even though no injury results. Those misusing laser pointers may be subject to disciplinary procedures under the Code of Student Conduct or the appropriate staff policies or be subject to possible legal action if injury results.