Will Staring at Guidance and Crane Lasers Cause Permanent Blindness?|
Article - May 18, 2017 By LarsonElectronics.com
Will Staring at Guidance and Crane Lasers Cause Permanent Blindness?
Most people assume that mainstream, low intensity lasers are capable of severely disrupting vision and causing permanent blindness. Reports from the Federal Aviation Administration (FAA) of pilots being affected by culprits shining laser pointers in cockpits (along with imaginary thoughts of planes crashing due to pilots going blind from lasers) have amplified such assumptions.
The truth is, most commercial lasers, including crane laser lights, laser pens and some medical-grade lasers used in outpatient procedures, are not capable of inducing permanent blindness. If this were the case, then people attending concerts with laser light shows would all come out blind after the event!
However, this does not mean that all lasers are safe to stare at for long periods of time. Some laser types and classes may cause injury – but these lasers are rarely encountered by civilians and are mostly used for scientific testing and military applications.
Laser Injury Statistics and Safety
To give you a better idea of how safe mainstream lasers are, we turn to statistics from the International Laser Display Association (ILDA). According to the organization, in 40 years of laser shows with over 140 million people exposed to over 14 billion laser lights, only a handful have reported injuries – even though most exposure levels were staggeringly above the Maximum Permissible Exposure thresholds set forth by experts.
In most cases reported, the company responsible for administering lasers in locations with high human activity used the wrong type of laser. Pulsed lasers are known to be more dangerous than continuous wave lasers, because of large amounts of energy that comes out of the unit. Hence, pulsed lasers should never be applied in facilities with busy workers. This is why guidance and crane lasers use continuous wave lasers during operation.
Dealing with Flash Blindness
In the worst case scenario, individuals may succumb to flash-blindness or see after-images due to direct exposure from a commercial, continuous wave laser beam. Such effects are temporary and normal vision should normalize after 15 minutes. According to the US Air Force, in order to receive direct exposure from a laser, the central component in a person’s eye, that is the size of a pinhead, must be lined up directly with the laser, which is almost impossible to accomplish at far distances. Even at close distances, damage is considered to be insignificant and virtually non-existent.
The US Air Force suggests that the reason why people think their eye was injured is due to the reaction that takes place after laser exposure. Most individuals start rubbing their eyes, irritating the organ and causing after-images to appear. Moreover, discomfort from seeing a laser (note: not direct exposure) is not classified as an eye injury.
Retinal damage can occur if the wrong laser type was administered. Such injuries typically heal after 3-7 days; and in most cases, vision is fully restored. An example of this comes from a 2008 Aquamarine Open Air Festival event that took place in Moscow, Russia. Event organizers unintentionally pointed a pulsed laser light machine at the audience instead of the sky, as a way to avoid rainy weather conditions. As a result, digital camera sensors were damaged and people reported eye injuries with partial vision loss. This event is the third mass injury reported arising out of incorrectly applied, pulsed laser beams. A characteristic of pulsed lasers is dotted patterns, appearing in short bursts. Continuous wave lasers appear solid and are not harmful to humans. Pulsed lasers are safe when they are pointed at the sky or scanned above the heads of crowds.
In the Army, non-foveal retinal lesion injuries related to laser exposure are considered minor (classified as “Minor Injury”). A solider diagnosed with such injuries are allowed to commence duty without further consultation from a doctor. It is expected that the injury will heal on its own over time. For commercial pilots that report visionary obstruction from low-grade laser pointers to the FAA, the level of harm or danger is much lower than “Minor Injury” and is classified simply as “Bright Light or Glare”.
Laws and Regulations
Despite mainstream lasers being harmless, pointing laser pointer beams at aircrafts, including their flight path, is considered to be illegal. The prohibition on such activities was signed into law by ex-President Obama in 2012 (CDRH: 21 CFR 1040.10/11). Failure to abide by this ruling will result in a maximum prison sentence of five years and fines up to $250,000. Authorized groups by the FAA, members of the Department of Defense or the Department of Homeland Security are exempted from this law. Furthermore, people using laser emergency signaling devices to issue a distress signal or warning will not get penalized under this ruling.
The FAA also governs the use of laser pointers, which is subject to civil penalties (up to $25,000). Surprisingly, the Food and Drug Administration (FDA) regulates the application and use of specific lasers in the US. In October 2016, the group issued a proposal to label all laser colors that are not red to be defective. This would ban the selling of green, blue and other non-red laser pointers in the country by manufacturers and importers of such products. It is important to note that laser beams used for “surveying, leveling and alignment” (SLA) control are not part of this proposal. Hence, crane laser lights and other laser products used for industrial applications would still be useable, regardless of the final ruling of the proposal.