New from Scientific American科學人一分鐘聽力又來了！雷射筆傷眼，別直射眼睛！
Most Laser Pointers Are Too Strong
Federal researchers美國聯邦政府研究員 find that most green laser pointers and half of red ones are stronger than safety standards permit安全標準許可, creating an eye hazard雙眼的危害.
Laser pointers雷射筆 are helpful when giving a presentation提案. Just don’t let the beam光束 hit you in the eye—especially when it’s green. The National Institute of Standards and Technology美國國家標準技術研究所 says that nearly 90 percent of commercially available商用型 green pointers and about half of red pointers they tested are too strong and violate違反 federal safety regulations聯邦安全規範.
Green lasers use a shorter wavelength較短波 of light than red ones, making them brighter and more dangerous. The darker part of the retina 視網膜heats up灼傷 from the green laser’s intense強烈, yet invisible隱形的, infrared紅外線 light, which can cause retinal scarring視網膜灼傷 and even blind spots(導致)視力出現中央盲點. Because the damaging wavelengths are invisible, the eye’s natural defense mechanism—its eyelid—doesn’t close to provide protection.
Airline pilots are well aware of these dangers: in 2011 alone there were more than 3,500 cases of lasers being pointed at aircraft. In July 2012 one unfortunate JetBlue 美國廉價航空捷藍pilot suffered an eye injury when someone on the ground shined a green laser through his cockpit飛機駕駛艙 window. Luckily, the flight landed safely. Unluckily, it didn’t land on the person pointing the laser.