Table of Contents Does "Eyesafe" really mean "eye safe"? Are lasers hazardous if they only emit invisible light? Who do I call if I need technical help for laser safety? Are classroom laser pointers and laser key chains safe? What do the laser classes mean? Does "Eyesafe" really mean "eye safe"? NO! More and more manufacturers of lasers are reporting that their laser is "eye safe" because it emits laser radiation somewhere between 1500 nm and 1800 nm (mid-IR). Although the eye is much less susceptible to damage from these wavelengths, a damage threshold does exist. If a person is exposed to enough Erbium:YAG (1540 nm) laser energy, they WILL receive eye damage. This is not a hypothetical argument. Most mid-IR lasers can exceed safe limits for both the eye and the skin. A better term for this wavelength range would be "eye safer". Are lasers hazardous if they only emit invisible light? Actually, this is not a logical question. "Light" typically refers to the visible radiation portion of the electromagnetic spectrum. However, laser emissions can be (and often are) not visible to the human eye. Laser radiation does not need to be visible to cause damage. Most lasers used by the Navy & Marine Corps emit non-visible energy. Both visible and invisible laser emissions can produce damage to the eye, skin, or both. Who do I call if I need technical help for laser safety? The list of contacts is available here. For technical assistance with laser safety, contact the LNTL. Are classroom laser pointers and laser key chains safe? Classroom laser pointers are safe when used properly. It is recommended that whenever possible, Class 2 laser pointers should be used in lieu of Class 3a laser pointers. The Laser Institute of America has published a paper on the safety of handheld laser devices. What do the laser classes mean ? Laser classes are a means of categorizing lasers into groups based on the appropriate safety control measures needed for those lasers. Although most lasers will have the same classification based on the FDA regulations as they do based on the ANSI Z136.1, there are some exceptions. Most notable of those exceptions is that the FDA requires class IIIa lasers to be visible only (400-700 nm), while the ANSI Z136.1 allows invisible class 3a lasers. Another difference (although less dramatic) is that the FDA uses Roman numerals and the ANSI standard uses Arabic. The following is a list of current ANSI laser classes: ANSI Z136.1 Classification Description Class 1 Class 1 lasers are lasers that inherently cannot emit radiation in excess of the Accessible Emission Limit (AEL). This does not, however, mean that the system is incapable of doing harm. ANSI classification is based only on unaided and 5-cm aided viewing conditions. Therefore, skin hazards and aided viewing with a greater optical gain than 7.14 (5-cm optics) can still pose hazards. Class 2 Class 2 lasers are low power visible (400- to 700-nm wavelength) lasers and laser systems which cannot emit radiation in excess of the AEL based on a 0.25 second exposure. These lasers are not considered hazardous for momentary unintentional exposure. Invisible lasers and single pulse lasers cannot be class 2 lasers. Class 3a - Caution Label Class 3a lasers include lasers with an output between 1 and 5 times the class 1 (class 2 for visible lasers) AEL. Maximum beam irradiance or radiant exposure must not exceed the MPE to have a "Caution" label. Class 3a - Danger Label Class 3a lasers include lasers with an output between 1 and 5 times the class 1 (class 2 for visible lasers) AEL. Maximum beam irradiance or radiant exposure exceeds the MPE to have a "Danger" label. Class 3b Class 3b lasers are medium power lasers. All lasers not defined by a lower classification and with an average power less than 500 mW and unable to produce more than 125 mJ in 0.25 seconds are defined as class 3b. (other limitations apply, see ANSI Z136.1 for complete details.) Class 4 Class 4 lasers are high power lasers including all lasers in excess of class 3 limitations. These lasers can often be fire hazards.