The Truth Behind Computer Vision

Will your beloved time with your computer, smartphone, and tablets come back to bite you in blurred vision? Learn how to preserve your eyesight in an increasingly digital world

February 2, 2011

If you find yourself looking in the mirror at the end of a long day only to see the bloodshot eyes of a crackhead staring back at you, it may be because you are addicted to something—your digital devices.

A new problem that some eye experts are calling computer vision syndrome (CVS) is sweeping the country; it can affect up to 90 percent of people who spend two or more continuous hours a day with their eyes glued to a screen, whether it's that of a computer, an e-reader, or a smartphone. The symptoms, which can include blurry vision, headaches, dry eyes, or even long-term nearsightedness, may accrue over a period of days or months—but don't wait until you sense something is wrong. Start preventing the problem today.


Troubled Outlook
"Our eyes have evolved for three-dimensional viewing," says New York City–based optometrist Andrea Thau, O.D., of the American Optometric Association, "so we wind up overfocusing as we strain to find a 3-D image on a close-up 2-D screen."

What's more, the eye's natural focal point lies about 20 feet in front of the face. Most people, however, sit less than two feet from their computer screen, forcing a ring of eye muscles to continuously contract in order to redirect focus. If you stare at any sort of digital monitor for hours, those eye muscles can become so overwrought that they can't relax, even after you look away. The resulting blurred vision, a main CVS symptom, often clears up in as little as a few seconds, but if you hit this hazy point a lot—as in several times a day, most days of the week—then the short-term nearsightedness might become permanent. (It's still up for debate whether or not the problem is reversible. The American Optometric Association warns that it might not be, while the American Academy of Ophthalmology, an M.D. association, considers CVS to be a temporary, day-to-day annoyance that improves as soon as you take some time away from staring at a screen.)

One thing that's, er, crystal clear is CVS's other big troubling symptom: dry eyes. Parched, itchy peepers may sound trivial compared with lost vision, but frequent dryness can lead to infection.

The thing is, your eyes can't differentiate between a mind-numbing spreadsheet and a flirty e-mail from the hot guy you've just started dating. To them, any on-screen activity is so captivating that blinking typically becomes an afterthought. Case in point: A recent study found that most people blink an average of 16 times per minute, regularly whisking away debris and keeping their eyeballs well-oiled for optimal function. However, when settled in front of digital screens, those same people blinked fewer than six times per minute, leaving the door open for seriously dry, irritated eyes.

Save Your Sight
Chucking your computer, iPad, or smartphone and taking up an Amish-like 19th-century lifestyle isn't necessary; most CVS symptoms can be controlled. The first step: Start living by a simple 20-20-20 rule, says Thau. Look away from your screen every 20 minutes for 20 seconds and focus on a fixed point 20 feet away. Set an alarm via to remind yourself to get into the habit. Like any exercise, this eye movement works best when practiced regularly, but every little bit will help.

Next, make sure your workstation—at the office or at home—is set up so that your eyes are level with the very top of your monitor, says Louise Sclafani, O.D., director of optometric services at the University of Chicago Medical Center. Your eyes focus best when they're looking downward, she notes, and partially closed lids can combat dry eyes by preventing tears from evaporating. Cutting down on any annoying glare helps too. If you're holding a smartphone or e-reader and have to cup one hand over the screen to read the words on it, you could be straining your eyes and risking CVS, according to the American Academy of Ophthalmology. Close the blinds, adjust your device's contrast or brightness levels, or buy an inexpensive antiglare cover.

Still holding on to your 20/20? Even if your eyesight is top-notch, you may want to consider getting fitted for computer glasses, says Thau.

Unlike corrective lenses for near- or farsightedness, these reduce eyestrain by helping your midrange vision. Your doctor can even prescribe an all-in-one pair of lenses that will correct CVS and any other sight issue. (That said, always make sure the prescription you have is up to date; even a slight uncorrected flaw in your vision can exacerbate the symptoms of CVS.)

Above all, when in doubt, blink it out. Whenever you sit in front of a screen for hours at a time (and for most people that's practically every day), try to remember to combat overly dry eyes by blinking very slowly—as if you're fading off to sleep—every so often. Small breaks and a healthy perspective are the keys to beating CVS. "Yes, computers can be a visual challenge for our eyes," says Thau, "but when used with caution, they won't do permanent damage."

You can do a lot to keep your eyes healthy.