Eye contact with Class 3B laser beam

A graduate student and research assistant were assembling optical components for a Class 3B laser with a beam that had been split into two by an acousto-optical device. The process involved inserting a power meter, used to measure the optical intensity of the beams, into the laser path. The student did not realize that the meter had a highly reflective surface, which was different from the previous meter he had used in the past. As he inserted the power meter into the path of the laser, the beams reflected off of the surface of the detector and into the left eye of the research assistant. Neither individual was wearing laser protective eyewear at the time of the incident, despite the open laser beam. 

The laser power of both beams together was approximately 77 mW. The power of the reflected beams, combined, was approximately 3 mW, which is nearly three times the maximum permissible ocular exposure. 

On the advice of the U of A Radiation and Laser Safety Officer, the research assistant went to the emergency department for an eye examination. Fortunately, the eye was not damaged. 

Following the incident, an administrative review of records revealed that the lab was not authorized for laser use due to outstanding corrective actions related to a laser safety inspection performed a few months earlier. 

Hazards and Controls

Class 3B and 4 lasers are commonly used for research purposes at the U of A. These classes of lasers, which may also be part of confocal microscopes, imaging systems, and other equipment, are hazardous for skin or eye exposure and may cause burns and other eye damage, such as the development of cataracts.

Research groups that wish to operate Class 3B and 4 lasers at the University of Alberta must follow the instructions and safe operating guidelines below:

1. The Principal Investigator (PI) who will be leading the research must apply for authorization to use the equipment in a specific location. This step is to ensure that the space and equipment are suitable for the proposed use. 
2. The application must include all Class 3B and 4 lasers intended for use in that space; only the lasers and labs listed on page 1 and 2 of the valid registration certificate may be used.
3. The PI is responsible for ensuring that all authorized users are familiar with and comply with the terms and conditions of the registration certificate.
4. All prospective users of class 3B or 4 lasers must complete the Laser Safety eLearning course and be approved by the Registration Certificate Holder or designate.
5. All authorized users, including the PI, must wear proper personal protective equipment including  laser protective eyewear when working with open beam Class 3B and 4 lasers.

Users must introduce optical objects into the beam path in a safe manner by switching off or blocking the beam before introducing the object into the beamline. A shutter, beam block, or the laser power off button may be used to stop the beam. This process will minimize the risk of stray beams reflecting off the object(s) being introduced into the beamline.

Learn more about safe use of lasers at the University of Alberta.