Green lasers can harm the eyes

Laser pointers can be more dangerous in green than in red. A woman damaged her eye after looking directly at a green laser pointer for seconds. Portions of her retina had changed colour after she looked directly at the green laser at different periods of time for less than a minute. This is a sign of damage. The woman did not experience any loss of vision, and in 3 weeks, the damage started healing. Researchers from the Mayo Clinic in Rochester, Minnesota found that if the woman had spent longer looking at the laser, she could have suffered visual loss. Previous studies have shown that looking directly at a red laser pointer for 15 minutes cannot produce the same damage, which the woman experienced after 60 seconds. The eye is much more vulnerable to damage from the green laser pointer than the red laser pointer. Green is made up of shorter wavelengths than red, and the retina is more sensitive to shorter wavelengths. People think of the green laser as they do of the sun, which is okay to glance at occasionally, but dangerous if looked at for too long. To investigate how the green laser might damage eyes, researchers asked a 55 year-old woman with cancer in her eye, for which the only treatment was removal of the eye to look directly at a class 3A green laser pointer for different stretches of time, before she underwent surgery to remove the eye. After the experiment, the researchers saw that a portion of her retina had changed from its normal colour of orange-red to yellow, a sign the laser had damaged the retina. The damage matched what people can do to their eyes after staring at a solar eclipse. People use laser pointers for many reasons, such as giving lectures. Green lasers are less popular than red lasers, but green is easier to see in the night sky, and is therefore often preferred by amateur astronomers.