A comprehensive resource for safe and responsible laser use



Facts and commentary on the Feb. 2012 Winthrop Mass. laser misused at a girls’ hockey game


On Feb. 29 2012, a parent aimed a laser at high school girls during a hockey playoff game in Winthrop, Mass. A goalie said the laser went in her eyes twice, and she had headaches after the game. A summary of the facts is here. The page below gives additional facts and informed commentary relating to this widely-publicized incident.

Laser hazards


It is unlikely that the goalie would have an eye injury (retinal burn or lesion) from the laser exposure. While we don’t know the power of the laser pointer, or the time during which the light was in her eyes, eye injuries from consumer laser misuse are rare. Usually it takes a long and deliberate exposure, such as a 15-year-old boy who bounced the beam off a mirror into his eyes to “make a light show.”

While powerful laser pointers can pop balloons or light cigarettes up close, it is very difficult to hand-hold a laser on a moving target many yards away long enough to raise the retinal temperature enough to cause damage. (By the way, if you are doing a media report on this issue, it would be wrong to show dramatic effects of a laser close up, and then to imply that the same thing would happen in the Winthrop game situation. A more accurate simulation would be to hand-hold a laser on a moving balloon or moving cigarette located 10-20 yards away, and try to pop the balloon or light the cigarette. This is difficult or impossible, even with a powerful handheld laser.)

Many more details about laser pointer accident rates and hazards are discussed at the bottom of this page.

If the goalie has eye health concerns


If the Medway-Ashland goalie is worried, she should look at a blank white wall or a clear blue sky. A laser-caused lesion will show up as a black spot or spots, or a similar loss of vision, in the visual field area where the laser flashes were seen. There could be other causes of such spots, such as floaters in the eyes, so having spots or a vision problem alone does not mean the Winthrop laser is the cause. But it would indicate that the goalie should have an evaluation, preferably by a retinal specialist. Even without the spots, if the goalie or her parents have any concerns -- or perhaps for potential use in a lawsuit -- then it can’t hurt to have a retinal exam, as soon as can be arranged. More information is on the laser treatment page.

UPDATE March 4 2012: The goalie did see a doctor after the game “just to be safe”, according to 7 News WHDH.com.

Arrest the parent?


Should the parent who aimed the laser pointer be charged? In the opinion of LaserPointerSafety.com: Yes, absolutely.

The Winthrop parent deliberately aimed a laser beam at a person’s face. Perhaps if the laser had been shined only on the ice, in order to create a distraction, the incident could be chalked up to ignorance or a “prank.” But deliberate aiming at a person’s face should be treated as assault, and actually having the beam in the eye should be treated as battery.

It does not matter if the beam irradiance was low enough not to cause retinal injury. The general public does not know how to do laser power and divergence measurements, and laser safety calculations. Even if the beam irradiance is accurately known to be eye-safe, that does not make it right or legal, in our opinion, to deliberately aim towards a person’s face without his or her informed consent.

In our view, there is no doubt that the parent should be charged under the appropriate laws involving assault, battery, harassment, etc. Also, the parents of the goalie may wish to consider filling a civil lawsuit as well.

UPDATE March 4 2012: A WHDH news report states that this is the second time the parent has lased a girls hockey game. According to a former coach of the Wilmington High School team, the same man aimed a laser pointer at Wilmington players in a game about one year ago. He was escorted out of the rink on that day. In the opinion of LaserPointerSafety.com, this makes it even more imperative that charges be brought, as the man obviously did not learn his lesson from the earlier incident.

UPDATE March 7 2012: Joseph Cordes, 42, will be charged with disturbing the peace, a criminal charge. If this is the only charge brought against him, this seems inadequate in our opinion. LaserPointerSafety.com believes that Cordes should also be charged with assault, or similar, for aiming the laser at the goalie’s face and eyes. More on this is in our updated news item about the game.

Was the game fair?


Can lasers distract players enough to affect the outcome of a game? In many cases of laser misuse against professional athletes, there does not seem to have been a direct or significant effect on the game. In a recent U.K. case, a soccer captain scored the winning goal just after having a laser pointer shined in his face. In a 2011 soccer game, a German player was lased before a penalty kick that he missed, but he later denied that the pointer caused the miss. (We have a selected list of these and other laser incidents during soccer games here.)

In the Winthrop hockey game, news reports indicate that the laser was used for perhaps a few minutes during the third period. There was one goal scored by Winthrop at about the time that the Medway-Ashland goalie had laser light in her eyes. The final score was 3-1 in favor of Winthrop, indicating Winthrop made two laser-less goals. According to the Massachusetts Interscholastic Athletic Association, referees felt the laser did not affect the play. Apparently there were no complaints during the game that anyone’s play had been affected by the laser beam. The MIAA said, in a letter denying an appeal, that the decision of the referees was final. Based on the Division 1 tournament seeding, Winthrop as the number 8 seed may have been more likely to win than 25th-seeded Medway-Ashland. (Info on game conditions and tournament seeding from MetroWest Daily News.)

But every situation is different. Seeding does not determine outcome; otherwise, there would be no point in playing a tournament. Certainly, distraction either by a moving green laser dot, or much more directly by laser flashes in the eye, does not help an athlete’s performance. The effect of a parent lasing on high school girl athletes could be more severe than the effect of an anonymous fan lasing a professional athlete.

Unfortunately, the outcome of this game -- for both sides -- will be forever tainted because of the parent’s inexcusable actions. Even if part or all of the game should be replayed, another level of arguments would ensue over whether that result reflected the “right”, laserless outcome. Ultimately it is an unanswerable question whether the outcome of the Winthrop game would be different if the laser had not been used.

Helpful pages


Here is a list of pages here at LaserPointerSafety.com which may be useful:




More details about laser pointer safety


How many people have been harmed by consumer lasers?

One blogger commenting on the Winthrop case quoted a Princeton University web page as saying that more powerful laser pointers “present a significant potential for eye damage.” This is partially true. Certainly, the more power a laser has, the higher the potential for eye damage, all other factors being equal. But do laser pointers cause such damage in the real world?

It turns out that cases of accidental (non-deliberate exposure) eye damage from consumer lasers are very rare. On average, there are 1.7 complaints each year of laser-caused eye effects (discomfort or pain) or damage (retinal lesion or burn) that are reported to the U.S. Consumer Product Safety Commission, based on 2000-2010 incident monitoring.

Even the most powerful consumer lasers sold appear to not be causing significant numbers of injuries. In June 2010, the first consumer lasers with a power of around 1 watt (1000 milliwatts) were introduced. These are 200 times more powerful than the U.S. legal limit for a laser to be sold as a pointer. They can definitely cause instant retinal burns at a close distance. Yet from June 2010 to Feb. 2012, there have been no reported injuries from commercially sold 1 watt consumer lasers that LaserPointerSafety.com has been able to find. There have been two reports of hobbyists who made their own 1-watt lasers accidentally injuring themselves. In one case there was no long-term effect; in the other case the person will have a small off-center blind spot.

Of course, laser pointers need to be used responsibly. One important reason is the risk of causing eye effects (temporary discomfort) or in extreme cases eye damage (retinal lesion or burn). Other reasons include avoiding dangerous distractions such as to drivers and pilots, and also the simple courtesy of not annoying or harassing other persons. In the Winthrop case, the parent aiming the laser pointer was unsportsmanlike as well.

We have compiled some news reports of claimed and actual laser pointer eye effects and injuries. As you read these, keep in mind the difference between eye effects such as temporary pain and watering eyes, and actual eye injuries such as a retinal lesion or burn.

How much eye damage can a laser pointer cause?

In the U.S., lasers must be under 5 milliwatts to be legally sold or marketed as a laser “pointer”. (Higher powered lasers can legally be sold if they meet U.S. FDA product requirements and if they are not sold as “pointers” or for pointing applications. More details are here.)

So let’s say a person has a laser pointer that is just under 5 milliwatts. We’ll also assume the pointer has a tight, 1 milliradian beam divergence. Such a laser has a Nominal Ocular Hazard Distance (NOHD) of 52 feet. This means that laser experts say it is safe for the direct beam to enter a person’s eyes if he or she is farther than 52 feet from the laser.

A very important point is that this does NOT mean that the laser will cause eye damage at 51 feet, or even at 40 or 30 feet.

The reason is that there is a safety factor built into the concept of NOHD. Scientists first determined what laser power it took to cause the smallest detectable change to the retina in 50% of test subjects. They then set the Maximum Permissible Exposure to be 10 times lower (e.g., 10 times safer) than this level.

For the NOHD, this translates into a safety factor of 3.16. If you have a 5 mW pointer with an NOHD of 52 feet, there is a 50% chance of having a minimally medically detectable retinal lesion if you are within 16.5 feet (52 divided by 3.16). Further, this is under laboratory conditions, where the laser and the eye are both fixed in position relative to each other. Such a minimally detectable lesion may not cause a visible change to a person’s everyday vision, and the lesion may heal in the same way that cuts and burns on the skin heal.

What all this means in the real world is that it is difficult to use a laser pointer to deliberately cause an eye injury to another person. The laser light has to be on the eye long enough to heat up the retina. But it is hard to keep a beam on target when hand-holding it at any significant distance. Normally, the person hit by the beam will involuntarily close their eyes and turn away. (That’s why documented laser pointer injuries often turn out to be self-inflicted by persons who deliberately kept their eyes open.)

Our goal: more accurate laser safety knowledge


Again, we are not saying that laser pointers are always safe, or can be misused with impunity. We fully support safe, responsible use of reasonably powered lasers. We fully support laser safety concepts such as the Maximum Permissible Exposure limits, and the Nominal Ocular Hazard Distance.

Our goal is to accurately describe laser safety facts. Unfortunately, may people misunderstand or oversimplify the potential hazards of consumer lasers.

  • The most egregious error is to think that effects seen within a few inches or feet of the laser -- such as popping balloons or burning cigarettes -- will also happen at distances of many yards or miles.
  • The second most common error is to think that a laser will definitely cause a serious eye injury if a person is closer than the hazard distance (e.g., NOHD). As explained above, there is a safety factor in the NOHD calculations, plus they are based on an “injury” as being the smallest medically detectable retinal lesion. For a laser pointer to cause a permanent lesion or a noticeable visual spot usually means the laser was close to the eye and almost always involves a deliberate exposure where a person overcomes their aversion to bright light.