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Laser Safety Manual Contents

Scope and Applicability

Overview of Safety Requirements for Lasers

Laser Safety Organization at ASU

Laser and Laser System Classification

Registration and Permits

Laser Hazard Control Requirements

Emergency Procedures

Appendix A:
Laser Hazards

Appendix B:
Controlling "Non-Beam" Hazards

Appendix C:
Exposure Limits and Laser Classification

Appendix D:
Laser Control Area Permit

Appendix E:
Medical Surveillance Form

Appendix F:
Eye Injury Wavelengths Diagram

Appendix G:
Example SOP & Safety Checklist

Appendix H:
Procedures for Establaishing Medical Surveillance

Appendix I:
ASU Radiation Safety Committee Laser Policy

Appendix A - Laser Hazards

    The intensity of laser radiation is often such that exposure can result in serious and permanent injury to skin and eyes. There are also a number of non-beam hazards associated with laser systems. These include electrical shock, exposure to dyes and chemicals, and production of potentially hazardous beam plumes.

    Eye Injury

    The site of injury following laser exposure depends on the wavelength (Figure 1). Ultraviolet with wavelengths from 0.2 to 0.215 mm and infrared with wavelengths of 1.4 mm or greater are absorbed in the cornea. Wavelengths from 0.78 to 3 mm are also partially absorbed in the lens. Visible light 0.4 to 0.78 mm is transmitted to the retina. Some light with wavelengths from 0.78 to 1.4 mm will also be transmitted to the retina.

    Acute exposure of the cornea can cause corneal burns, or photokeratitis (welder's flash). Lens opacities (cataracts) are associated with chronic exposure of the lens. Chronic exposure of the retina may also result in retinal injury.

    All injury described above may be permanent and serious. Exposure of the retina can be particularly hazardous, however, as a result of the focusing effect of the lens. A laser beam originally several mm in diameter may be focused to a spot on the retina of 10 to 20 um diameter. The irradiance of the original beam is intensified in this manner by a factor of 10,000 or more!

    Objects in the center of the field of vision are focused on an area of the retina called the fovea. This area of the retina is the most sensitive and is responsible for most of our visual acuity. Injury of the fovea may result in permanent blindness in the injured eye. If the peripheral areas of the fovea are injured, the effect on vision is less serious. In some cases the effects are not noticeable or distracting. See Appendix F.

    Skin Injury

    Skin burns are caused by radiation from high-powered lasers in the infrared. Exposure to the skin in all wavelengths may result in erythema, skin cancer, skin aging, dry skin effects, and photosensitive reactions in the skin.

 


  
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