En español | As the coronavirus pandemic has driven many of us online for work, meetings and even socializing, sales of computer glasses are on the rise. But what do these glasses really do? Are they worth buying?
Short answer: probably not. Most computer glasses are designed to filter out blue light — high-energy light rays emitted from the display screens on your computer, tablet and phone. Manufacturers of computer glasses claim that too much exposure to blue light can lead to dry eyes, blurred vision, eye fatigue, headache and other symptoms of digital eyestrain.
While it's true that hours spent staring at your screens can cause all those problems, the blue light isn't to blame, says Anne L. Coleman, M.D., president of the American Academy of Ophthalmology (AAO) and professor of ophthalmology at the University of California, Los Angeles.
"The literature shows there is no evidence of any harm from blue light to the eyes,” Coleman says, “and there's no evidence that shows blue-blocking lenses or filters make any difference at all."
Indeed, a 2019 study published in Optometry and Vision Science found that blue-blocking filters were no more effective in reducing digital eyestrain than neutral light filters that don't block out blue light.
So what is to blame for your tired, bleary eyes? Blinking. Or more specifically, not blinking when you're staring at your screens, Coleman says.
"When you're at the computer, you're focusing, and research shows that your blinking frequency decreases,” she says. “Under normal circumstances, we blink about 15 times a minute, but we blink half of that to one-third of that amount when using digital devices. That's hard on your eyes.”
So instead of buying a special pair of glasses you don't need, follow these steps:
Apply the 20/20/20 rule
You can avoid digital eyestrain by simply giving your eyes a break at regular intervals, Coleman says. “In ophthalmology, we have a rule for computer time that every 20 minutes you should look at something about 20 feet away for 20 seconds. Now it can be hard to remember to do that, but even if you give your eyes a break once or twice an hour, it can really help,” she says.
Lubricate your eyes
As we get older, our tear production declines and increases our risk for dry eyes. Blinking less frequently while on the computer exacerbates the problem, says Timothy G. Murray, M.D., president of the American Society of Retina Specialists. “As your cornea becomes less lubricated, things become blurry, your eyes feel gritty, and your eyelids may droop a little bit as they try to protect against the dryness. You can avoid this by using artificial-tear eye drops to lubricate your eyes.”
If you find yourself needing to use drops more than four times a day, the AAO recommends buying preservative-free drops, as many people find the preservatives can irritate their eyes.
Increase the font size
Another underlying cause of computer-related eyestrain is that your eyes are working hard to focus on words or images at a somewhat odd distance: A computer screen is farther away than you'd hold a book and closer than you'd be from your TV. “You can buy computer glasses for the exact distance you need,” Murray says. “So if you sit 21.5 inches from your screen, you can get glasses that are focused exactly at that distance. But I haven't really found that helpful for my patients."
The problem with that approach is most people are using laptops, tablets and/or auxiliary monitors, so the distances from their screens vary. The easiest solution in such cases is to simply increase the font size to a comfortable reading size on all of your screens, Coleman says. “That way you're not fiddling with glasses every time you want to see what you're working on."
Adjust the contrast
Boosting the contrast on your monitors also can take the strain off your eyes, Coleman says. “More contrast is always good, especially for older adults. As we mature, we all start to develop cataracts — a yellowing or clouding of the lens of the eye. Contrast helps the light go through that yellow filter, so it will be a bit easier to see,” she says.
Too much glare — light that is brighter than the eyes can comfortably handle — from your screens can also lead to eyestrain, Coleman says. “A matte screen filter can help reduce glare and make computer time easier on your eyes."
Buy a better monitor
Finally, a new monitor can do wonders for tired eyes, especially if you're staring at a small laptop screen all day. “You can buy big, high-resolution screens that allow for very easy viewing,” Murray says. “The higher the pixel resolution, the sharper the text and images look, and the easier it is on your eyes to focus.” Many affordable auxiliary monitors are now available in 4K (considered ultra high-definition) resolution.