"Why isn’t he more careful when pointing that laser beam?” I wondered during a recent lecture. The speaker was careless with the red beam, casting it about before pointing it at the screen.
I knew lasers could damage eyes. When used for treating medical problems, protective glasses must be worn, but I had no idea whether the use of a laser pointer was dangerous. Now I know.
Dr. Martin K. Schmid, an ophthalmologist at Lucerne Cantonal Hospital in Lucerne, Switzerland, reports in the New England Journal of Medicine the case of a 15-year-old boy who wanted to have a little fun. So he purchased a laser, thinking he would burn a hole in his sister’s sneakers and pop balloons.
Later, this teenager became more adventuresome. He decided to create a laser show, using it in front of a mirror. It was a dangerous decision. In the process of becoming a movie director, he zapped his eyes several times with the laser beam. He soon discovered he had lost some of his vision and was afraid to tell his parents what had happened.
Two weeks later, Dr. Schmid and his ophthalmology colleagues discovered the boy’s left eye was so badly damaged he could not count fingers more than a meter away (about three feet).
Eye examination showed a dense retinal hemorrhage in the left macula. The macula is the part of the eye that provides central vision and allows you to see another person’s eye at 20 feet. Loss of this vision means you can no longer read. He had also lost some vision in his right eye.
A four months’ healing process had helped the boy regain some of his eyesight. But he continued to have blind spots in his vision due to the destruction of cells in the retina, the back part of the eye. The retina sends visual messages to the brain. This tragedy could have been avoided.
So what should parents and teenagers know about laser pointers that are shaped like pens? Dr. Schmid says that most lasers are not high-powered, having only an output of 5 milliwatts. And that those in the range of one milliwatt are generally considered safe.
But the word “generally” worries me. It should also concern parents. Under ideal circumstances children are saved from laser injury due to a normal reaction to light. If we encounter a bright object, such as a laser beam, we normally blink, saving the eye from damage.
But assuming this will happen is problematic. Young children are curious and may decide to stare at a bright object for a period of time. Their prolonged curiosity could result in loss of vision even from low-power lasers.
Besides, it appears there’s a bit of the Wild West in the lack of government control in the selling of laser devices. For instance, it has been “generally” believed that laser devices powerful enough to damage the eye were only available to the military.
But Dr. Schmid reports that the laser acquired by this 15-year-old boy had a power of 150 milliwatts. And there are even stronger lasers sold on the Internet in the range of 700 milliwatts. Websites also advertise laser swords that are supposed to be fun toys!
I find it ludicrous that laser devices are allowed to be sold without a big red danger sign on them. Surely it’s reasonable to ask, how can a child tell a harmless laser pointer (if there is one) from a dangerous laser?
There are other problems. A U.S. contact told me that since 2004, there have been 2,800 incidents of laser beams being directed at landing aircraft in the United States. This is a senseless act.
The chance of damaging eyesight is minimal, as the speed of the plane and short duration of the beam protects the pilot. But this evil practice can cause sudden “flash blindness” at a critical time during landing.
The constant message is that there are many ways for children to be injured. Some we cannot control, but good sense should be able to stop laser-eye tragedies.
Dr. Gifford-Jones is a medical journalist with a private medical practice in Toronto.