Spend five minutes on any busy street corner and you'll spot people using tablets and smartphones in dangerous ways, whether it's texting behind the wheel or strolling with their eyes on the screen.
But distracted driving and walking aren't the only perils lurking behind touchscreen devices such as iPads, iPhones, BlackBerrys, Windows Phones, and Androids. Although not quite as dramatic, other touchscreen-oriented health hazards are even more insidious because most people aren't even aware that they exist. The potential for injury from using touchscreens will only go up as more people use smartphones and tablets, especially if Microsoft's Windows 8 effort succeeds in popularizing touchscreen PCs and laptops.
Ergonomic risks are not new to computer users. Laptops and netbooks, whose sales now outnumber desktop computers by more than two to one, pose their own health-related problems. But the rise of the touchscreen means both new kinds of health hazards and more usage in risky scenarios.
[ Watch the "Safer Computing" guide to preventing repetitive stress injuries in your workplace: as a video or as a slideshow. | Learn why touch capabilities in Windows 7 failed and what Microsoft has in store for Windows 8's touch plans. ]
After decades of research on machine-human interactions, medical experts have pinpointed three categories of computer-related illnesses, both in traditional PC use and in the new class of touchscreen devices:
Repeated motion injuries. Commonly known as RSIs, for repetitive stress injuries, these ailments result from recurrent large or small movements that affect joints, muscles, tendons, and nerves. For example, people who frequently use their thumbs to type text messages on cellphones sometimes develop de Quervain syndrome, a painful affliction that involves the tendons that move the thumb. Although the causal link isn't as well established as in patients who suffer from pain from prolonged desktop keyboard use, there's little doubt that overzealous texting can cause debilitating pain.
Diseases caused by unnatural postures and forces. Closely related to RSIs, these disorders occur when people use their bodies in ways that induce physical stress, such as tilting their hands too far inward or outward while tapping or putting force on their wrists while typing. Carpal tunnel syndrome, perhaps the best-known disease in this category, results from pressure on the median nerve in the wrist.
Eyestrain. Struggling to read computer monitors, either because the characters and images aren't clear or because the screen is obscured by glare or reflections, may cause problems that range from annoying to incapacitating. Termed "computer vision syndrome" by some ophthalmologists, symptoms include eye pain or redness, blurred or double vision, and headaches.
Many people are also concerned about the radiation emitted by old-style CRT monitors and the cellular radios in smartphones and some tablets, as well as the Wi-Fi radios in various devices. The research here has been contradictory, though the risk is probably low if you follow the manufacturers' guidelines for safe use.
Thanks to efforts by government agencies, trade associations, and professional groups such as the Human Factors and Ergonomics Society, people who use desktop computers are now more familiar with strategies to reduce risk by choosing equipment wisely and using it properly than they were 10 or 15 years ago. Vendors of computers, accessories, and office furniture routinely plug the ergonomic advantages of their products, and manuals often include advice about how to work with them safely.
Regrettably, awareness about risks hasn't trickled down to the world of touchscreen devices and notebooks. Here are some of the ways notebooks and mobile devices can hurt you and what you can do to prevent injury.
First Up: Notebooks' Health Perils
For years, notebook users were forced to trade power for portability. No longer -- recent laptops rival desktop rigs in speed and storage. For many people, laptops pull double duty on the road and in offices and homes. Unfortunately, their design limits them ergonomically. Because the display and keyboard are attached to one another, you can't position them optimally at the same time.
For extended desktop use, an add-on monitor lets you place the keyboard at desktop height, with your elbows bent at a 90-degree angle and the top of the external display at about eye level, as the "Safer computing" video and "Safer computing" slideshow demonstrate. If that's too expensive, get a stand to elevate the laptop's built-in monitor, and buy a separate keyboard and pointing device.
Notebooks pose even more problems when you use them in casual settings or at an office's guest desk or a hotel room's desk, where it's harder to find positions that don't put too much stress on your neck, shoulders, arms, wrists, and hands. If you work on the road a lot, consider carrying a lightweight external keyboard and pointing device, then elevating the laptop with a phone book or other object.
If you insist on using your laptop in bed or while you're watching television on the couch, avoid the temptation to lie on your side with your head propped up on your arm: That puts stress on your neck and makes it nearly impossible to type or use a keyboard or trackpad in anything resembling a natural position. In bed, sit with your back upright, supported by a firm cushion, place a pillow beneath your knees, and angle the screen to minimize reflections from lights behind you. Even if you take these precautions, don't use the computer for more than, say, 5 or 10 minutes at a stretch without taking a break. If you have to work for more than a half-hour or so, move to a desk if you can.
Next Page: the problem with touchscreens...