You know that UV-blocking sunglasses protect your eyes when you’re outdoors, but there’s another part of the light spectrum—blue light, part of the visible light spectrum—that is getting a lot of bad press lately as being harmful. And blue light can be shining in your eyes during every waking hour, because besides being a part of sunlight, there’s also the manmade version of blue light emitted by LED lighting, flat-screen TVs and screens on computers, phones and tablets.

Blue light has the shortest wavelength and the highest energy on the visible light spectrum (only UV light, the invisible part of the light spectrum, is stronger), said Bottom Line expert Marc Grossman, OD, LAc, a holistic eye doctor in New Paltz, New York.

Laboratory studies have shown that too much exposure to blue light can damage the light-sensitive cells in the retina. This causes changes that resemble those of macular degeneration, which can lead to permanent vision loss, Dr. Grossman said.

Research still needs to determine how much natural and manmade blue light is too much for the retina, Dr. Grossman said, but eye care providers are already concerned that the amount of time patients spend looking at screens now may increase the risk of macular degeneration later in life. And in fact, studies have shown that people with macular degeneration tend to have had more exposure to blue light during their lifetimes. That’s a scary thought, but research done on mice and published in PLoS One found that blocking blue light significantly reduced damage to their retinas. So, it makes sense to take steps to reduce your exposure, certainly until we learn more.

There are a variety of ways you can filter blue light at work and home, notably device settings, apps and screen protectors. Some of these options reduce blue light 24/7, while others can be set to automatically turn on in the evening—this is especially helpful for getting better quality sleep because blue light interferes with sleep cycles (that’s one reason many sleep experts suggest turning off all devices one to two hours before you turn in).

FOR EVENING WEB SURFERS: CHANGE YOUR SETTINGS

If most of your screen time takes place in the hours before bed, enabling the “night mode” setting on your device in the early evening should be enough for you. This changes the colors on your screen to reduce blue light. Many phones and tablets have this as a built-in function, easily found under “settings” and/or “display and brightness.” For example, Apple offers Night Shift on the iPhone and iPad, which changes the color temperature of your screen from blue to yellow in the evening and back again in the morning. You can pick a set time for the change or allow it to change automatically at sunset and sunrise. On an Amazon Fire tablet, as another example, simply enable the Blue Shade setting to block blue light. If you use Windows on a PC, Night Light for Windows let you change your screens to warmer colors in the evening.

If your device doesn’t have built-in night mode settings, consider an app. The free Twilight app for Android phones filters blue light according to sunset and sunrise. It can be downloaded from Google Play.

FOR ROUND-THE-CLOCK USERS: CONSIDER APPS OR SOFTWARE

f.lux. is free software that filters blue light from evening to early morning on your computer whether you have a Mac or PC.  The limitation of using this software is that you can’t control when it kicks in—it does so automatically when the sun sets, and then changes again at sunrise. If you want more control, the free SunsetScreen for Windows app allows you to set the time at which the screen loses its blue and choose the amount of reduction.

If you’re on the computer day and night—at work and play—Iris software, created by a video game developer who spent long hours looking at screens, may be a big help.  It manipulates the blue light on your screen without the typical loss of brightness that comes from changing screen color and changes the screen’s “flicker rate.” It also reminds you to take breaks—all that helps you avoid eye discomfort. You can try it for free for one week and buy a lifetime license for $15.

If you just can’t seem to put your phone down—perhaps you’re scrolling through social media nearly 24/7—the free My Eyes Protection for Androids app will give your eyes a break in more ways than one. It has an “electronic paper” mode that makes your screen look more like paper, which is easier on your eyes. It also blocks blue light. And it reminds you to take breaks from your screen and do eye exercises. It can be downloaded from Google Play.

PHYSICAL FILTERS: PUT UP A BLUE-LIGHT BARRIER

There are two other options for filtering blue light: screen protectors and special blue-blocking glasses.

The advantage to screen protectors is that they filter blue light all the time—a good option if you’re on the computer well over eight hours a day.

Dr. Grossman recommends the screen protectors from Reticare. They adhere to your screen almost like a magnet and come sized for most electronics brands and models. Protector prices are $19.99 for a smartphone, $34.99 for a tablet, $49.99 for laptop and $69.99 for a computer monitor. They’re also made from material that doesn’t significantly change how you see the colors on your screen.

Blue-light filtering glasses, often called blue blockers, are an especially good option for people who are at a computer all day at an office—many glasses will also filter blue light from fluorescent lights. The model that Consumer Reports found blocks the most blue light is the Uvex Skyper, which costs under $10. If you wear prescription eyeglasses, talk to your eyecare doctor about having your next pair treated to block blue light.

AND ONE SUPPLEMENT…

Some nutrients help our eyes naturally filter blue light, said Dr. Grossman, who recommends taking eye-health supplements with…

  • Lutein, 6 to 20 mg
  • Zeaxanthin, 2 to 12 mg
  • Vitamin C, 2,000 to 3,000 mg
  • Astaxanthin, 6 to 12 mg