BY SUE MacDONALD
The Cincinnati Enquirer
The warning label on laser pointers is self-explanatory: "Caution. Laser light. Avoid direct eye exposure. Keep out of reach of small children."
That's because a laser, basically a concentrated and highly focused light beam, has the potential to damage the retina, the inner surface of the eye that collects and sends visual images to the brain for processing. Too much light can cause the retina to turn cloudy.
But laser pointers tend to be low-level, low-intensity lasers, and Cincinnati ophthalmologist Dr. Andy Aziz said he's read no medical reports of eye damage from them.
"A brief, few-second exposure, or even a minute exposure, is not going to be enough to do any damage," he says. Danger enters the picture "only if you are stupid enough to hold one at your pupil for a long time."
Dr. Lawrence Raymond, ophthalmologist at the University of Cincinnati, says retinal laser burns could occur after 10 seconds of exposure with some kinds of lasers, such as helium-neon lasers. Lasers are classified as hot or cold, depending on their power source and voltage. Laser pointers fall into the category of "cold" lasers, Dr. Aziz said.
One of the nation's largest distributors of laser pointers, MiracleBeam of Dayton, Ohio, uses beryllium oxide (otherwise known as oxide of ruby) to produce the light. "Those lights don't have any heat to them, and it's the heat that causes damage to the retina," Dr. Aziz says.
Commercially, higher-intensity lasers are used for surgery, to cut steel or send communication signals long distances.
Laser pointers use less than 5 milliwatts of energy, comparable to what's used in compact disc players. Eye surgery lasers use up to 1,200 milliwatts.
General advice:
- Don't point the lasers at people's eyes.
- If someone points a laser at your eyes, turn away.
- If you look at a laser, don't look for more than a few seconds.
