WEDNESDAY, Sept. 8 (HealthDay News) -- A 15-year-old Swiss boy attempted to create his own laser show using a laser pointer he bought on the Internet and a mirror. Instead, he inadvertently beamed the laser into his eyes, creating permanent damage to his vision.

"These high-power laser products are very dangerous," said Dr. Martin Schmid, head of the retina unit in the department of ophthalmology at Lucerne Cantonal Hospital in Switzerland. Schmid is also one of the authors of the case report detailing the young boy's eye damage in a letter in the Sept. 9 issue of the New England Journal of Medicine.

Schmid said that part of the problem is that not all laser pointers are labeled properly, so it's not always easy to know if you have a pointer that could create serious damage. One sure way to know if you have a potentially dangerous laser pointer is if the laser can burn through paper, explained Schmid.

"Every laser pointer which is capable of burning holes into paper or of lighting matches or of popping balloons is highly dangerous for the eye and must not be used by non-professionals," he cautioned.

Those are exactly some of the uses the Swiss youngster was planning for his laser pointer. He told doctors that he purchased the laser pointer so that he could pop balloons from a distance, burn holes in paper cards and burn holes in his sister's sneakers.

While he was attempting his "laser light show," the teen said that the laser beam hit his eyes several times. Although he immediately noticed that his vision was blurry, he was afraid to tell his parents what had happened. He waited two weeks before letting them know that he was still experiencing blurred vision.

The vision in his left eye was so damaged that he couldn't count how many fingers a doctor was holding up until they were just three feet away. His visual acuity in his right eye was 20/50.

Schmid said the boy wasn't sure if the laser was dangerous, and he definitely didn't know it could cause immediate eye injury.

When the teenager's eyes were examined, doctors discovered that there had been significant internal bleeding in the left eye and that there were several small scars in the right eye. Even with treatment, there's still a scar that diminished the boy's vision in his left eye. However, his visual acuity has returned to near normal, according to the report.

The laser used by the boy produced an output of 150 milliwatts (mW), far above the maximal output of 5 mW that's expected from a laser pointer sold to the public. The authors point out that it's possible to purchase laser pointers as strong as 700 mW, although such a device may not look any different than a lower-powered device.

Additionally, Schmid said there are instructions available over the Internet for turning low-power devices into high-powered ones.

And, the authors pointed out, high-powered laser pointers can produce immediate and severe retinal injury -- so severe that even blindness can occur.

Dr. Roy Chuck, chair of ophthalmology and visual sciences at Montefiore Medical Center and the Albert Einstein College of Medicine in New York City, said, "We've seen lots of cases of laser burns, usually from researchers giving presentations, but now we're seeing more cases of people ordering these products over the Internet, though eye injuries in lay people are still pretty rare."

Chuck said that children shouldn't have access to laser pointers. "They're not giving presentations, so why would they need to have them?" He said that when it comes to laser toys -- like those used for laser tag -- buying a well-known name brand may be helpful in this case. "When you're buying off the Internet, it's not as regulated and you just can't tell what the strength of the laser is," noted Chuck.

Schmid added that lasers used in toys will generally be labeled as Class 1, although he said that products aren't always labeled properly.

And, even if you've purchased a "safe" laser toy, it's possible that creative children may turn to the Internet and figure out ways to boost the power of the laser. "By searching YouTube for 'burning laser pointers,' you will find a huge amount of videos showing such dangerous experiments. Moreover, there is an increasing number of homepages and videos demonstrating how to turn legal low-power lasers into burning, high-power lasers," said Schmid.

More information

Learn more about laser pointer safety from the Laser Institute of America.