By Johnson, Douglas A.
The FBI Law Enforcement Bulletin , Vol. 68, No. 5
Over the past year, police in Europe and the United States have received reports of juveniles temporarily blinding subway drivers with laser lights. Also, reports of British sports fans aiming laser pointers at soccer players and American basketball spectators shooting lasers at the eyes of opposing players on the free throw line have surfaced.
Law enforcement officers in the United States have begun experiencing similar situations. Low-power, visible-light lasers, whether designed for use in the classroom, laboratory, or on the battlefield, are the easiest to obtain, detect, and most likely to be used by low-tech hooligans. They also may be used as an alternative to firearms because of favorable laws that do not define possession of a laser as a deadly weapon.
Law enforcement officers could encounter low-power lasers during routine operations, such as traffic stops, or in special operations, such as hostage situations. In most instances, light from this type of laser would not, for the reasons of power and length of time on the eye, cause actual eye damage. However, the laser's incredible brilliance could surprise and functionally disable officers. Also, ungrounded fear of permanent blindness could further impair their judgment. The susceptibility of officers to this type of debilitation remains largely psychological and would depend on their preparedness, training, and the conditions at the time of the incident. What is this new threat, and what can officers do to protect themselves?
Lasers and the Human Response
In simplest terms, a laser is an intensely bright light.(1) Unlike conventional light, however, laser light travels out from the laser device in a narrow beam maintaining its brightness at long distances. Some high-power laser beams can vaporize steel or other materials. Also, laser beams are not only visible (colors that range from red to violet within the visible color spectrum) but also invisible at both the infrared and ultraviolet ends of the color spectrum.
Although invented over 30 years ago, in the past decade, medical researchers, military authorities, and even criminals have found multiple applications for laser devices. Like computers and digital cameras, lasers also have become smaller, more powerful, less costly, and more available than ever before. Annual sales now exceed $1 billion.
Military uses of these lasers include range finding, target designation, and live-fire training (laser tag). Medical lasers, visible and invisible, are powerful and now as small as a suitcase but remain expensive and require line voltage as opposed to batteries. These uses represent some of the positive purposes of the technical advances in laser manufacturing. However, world arms merchants openly advertise invisible-beam laser weapons, notably of Chinese manufacture, which criminals obtain to use in such illegal activities as terrorist attacks and narcotics operations.(2)
While most lasers found outside of research laboratories or medical/industrial facilities cannot penetrate metal or even damage skin, the eye remains vulnerable. As laser light passes into the eye, it becomes focused by the cornea onto the retina. Located at the back of the eye, the retina is a layer of living cells that intense light (by causing highly localized heating of the area) can damage or permanently destroy. The actual effect on the eye will vary with the power of the laser, the length of time the laser remains trained on the eye, and the portion of the retina that the focused light impacts. The effect of looking into a laser beam can range from true blindness, to dazzling (similar to closely viewing a camera flash), to annoyance. In many cases, the effects will not last long, perhaps only several seconds to some minutes. Also, temporary irritation or the presence of afterimages (visual sensations occurring after the external cause has ceased) could last several days but eventually should disappear and cause no further problems. …