The major health risk for personnel working with lasers is the potential for eye injury. Electromagnetic radiation above X-ray spectrum penetrates the ocular structures to varying degrees, depending on wavelength, maximizing in the visible spectrum:
- <315 nm (far UV) -cornea
- 315-400 nm (near UV) -lens
- 400-1400 nm (visible and near IR) -retina
- 1400-3000 nm (far IR and microwave) -lens
- >3000 nm - cornea
The risk also depends on the power of the laser, and for lasers of medium power or greater, on the potential for possible reflections of surrounding surfaces. Lasers are classified as Class 1, 2, 3a, 3b, or 4 according to output (beam intensity in Watts/cm2 or radiation dose in joule/cm2 at specific wavelengths). High power lasers may produce additional risk to skin and associated hazards primarily related to the generating equipment, such as electrical shock and ionizing radiation.
Laser radiation should be discharged in a non-reflective and fire resistant background. All personnel should be cleared for a reasonable distance on all sides of the laser beam. A warning sign should be attached to the laser device in a conspicuous location to indicate the potential eye hazard associated with the laser. The correct safety goggles for the Laser class should be used in order to filter out the specific laser wavelength. All workers should have a pre-employment eye examination as well as a final eye examination. Contact the Faculty Safety Officer for advice on laser and licencing matters. Application forms for operator licence can be obtained at the Health Sciences Authority website at http://www.hsa.gov.sg/html/business/eforms.html.