Call it the law of unintended application: No matter one’s objective in developing a new technology, no matter how much the technology promises to address an important, heretofore unmet need in society, somebody will come up with an entirely inane — or at least unexpected — use for it. And soon enough no one will remember it ever having any other purpose. Here are five optics- and light-based technologies that have suffered such a fate. Videophones/Webcams On April 7, 1927, Herbert Hoover, then Secretary of Commerce, demonstrated the videophone — for the first time publicly — when he addressed a Bell Labs audience in New York from a video booth in Washington, D.C. He anticipated a wonderful future for the technology, noting, “every great and fundamental discovery of the past has been followed by use far beyond the vision of its creator.” He didn’t add: “I can only hope that, decades from now, videophones – or ‘webcams’ — will be wielded by amateur pole dancers and others who truly understand the sexy potential of the technology. Only then will all your work be worth it.” Laser pointers The price of the laser pointer dropped considerably in the late 1990s, finally making it accessible to the masses. Overnight, the device went from being a plaything of executives and academics giving presentations to becoming the bane of cats and moviegoers everywhere. Laser pointer abuse in theaters — with people shining the devices at screens, sending other patrons into fits of apoplexy — reached epidemic proportions. The sitcom Seinfeld famously riffed on this in a 1998 episode. In more recent years laser pointers have become a serious safety concern as nitwits everywhere have taken to shining them at airplanes and helicopters, distracting the pilots and potentially even blinding them (see: Blinded by the Light).Some 3,500 incidents were reported to the FAA in 2012 alone, including incidents involving dummies like this: Glow sticks Did you know that some of the earliest patents for glow stick-like devices were assigned to the U.S. Navy, who used the technology for emergency lighting, helicopter landing zone marking and other such applications? I didn’t. LEDs I wouldn’t call this one inane or unwelcome, but we definitely didn’t see it coming. When LEDs first appeared on the scene in the 1960s, they were largely used for indicators and displays in research and electronics test equipment and later in TVs, radios, telephones and those big, chunky calculators we had as kids. Hardly glamorous stuff. In recent years, though, LEDs have started running with a different crowd, in the world of haute couture. Several fashion designers have begun to incorporate LEDs into their work. These include Hussein Chalayan, who in early 2008 showed a series of LED dresses, each with 15,000 individually controlled LEDs allowing display of video imagery on the dresses. Cameras and sensors for autonomous driving Safety first, David Hasselhoff!