Laser pointers can be a fun tool for highlighting stars in the sky or for entertaining your cat, but misuse of green laser pointers may be dangerous. New research shows that shining a green laser pointer directly into the eye can cause long-lasting damage.
Green laser pointers have become increasingly popular because of their brightness -- they can penetrate into the night sky and point to a faraway building during daylight hours. But they may also be more dangerous than the red variety.
"We found that unlike a red laser pointer, a green laser pointer does cause visible damage to the retina and the pigment layer behind the retina," says Dennis Robertson, an ophthalmologist at the Mayo Clinic in Rochester, Minn.
He shined a green laser pointer into the eye of a patient who was going to have his eye removed because of a tumor. Sixty seconds was enough to damage eye tissue, leaving a scar later. Although the exposure did not damage the patient's vision, Robertson says that higher-powered lasers -- those greater than 5 milliwatts -- could cause functional damage within seconds.
Green lasers use a shorter wavelength of light than red ones, making them brighter and more dangerous.
Robertson doesn't think the tools should be banned, but he says people should be cautious when using them.
The findings were published in the May issue of Archives of Ophthalmology.