Who among us hasn’t looked up after hours of work—or a session of scrolling Instagram—with a pair of dry, strained, bloodshot eyes? Naturally, computer vision syndrome has become a simmering anxiety for many who rely on screens for a paycheck and a bogeyman for parents of digital-native children. We’ve now arrived at the commercial opportunism phase. Blue light blocking glasses promise to protect us from possible macular degeneration and eye strain, and they come in all the usual flavors of branding from fancy (Felix Gray) to scammy Amazon alphabet-soup—TIJN, FEYOLD, and ANRRI?

We’ll save you the $100 or so: “There's no evidence whatsoever that these blue blocking lenses reduce eye strain at all,” says Mark Rosenfield, a professor at the SUNY College of Optometry. “It was a question of people putting two and two together and making five.” Screens do give off blue light, and people do get eye strain from screens. But… there’s no evidence that it’s the blue light causing it.

There are more misconceptions where that came from. In fact, if you’re at all nervous that regular laptop use will make your precious 20/20 eyeballs leak from your sockets (not speaking from personal experience or anything), you’d be better off staring at your screen right now to learn how your eyes actually work.

As far as research has shown, digital eye strain is nothing more than a set of short-term symptoms. “There's no evidence that it causes either long term damage to the eyes or a change in prescription,” Rosenfield says. Still, hours of computer use definitely tires out eyes. It just has less to do with technology itself than the kind of work we do on screens.

Looking at something up close is known as near work: our eyes turn inward in order to focus. So reading or focusing on something in front of us, printed or digital, taxes our eyes. We also tend to blink less when doing that kind of work, which dries our eyes. The problem is we tend to look at screens for way longer than printed materials—like, hours longer. So the discomfort we feel is probably the same kind we’d feel if we read Moby Dick in one sitting. It just seems like it’s our computer’s fault.

So maybe you still feel tethered to reading a Moby Dick’s worth of emails and hot takes every day. Fine! You’re still not cursed to a lifetime of desperate Visine overuse, but you need to find ways to give your eyes a break. Follow the 20-20-20 rule: every 20 minutes, stare at something at least 20 feet away for at least 20 seconds. It works!

While you’re doing that, take note of the window situation in your office. Does your computer screen face a bright window and bounce glare into your face? That makes it harder for your eyes to focus. So does any great difference between your office’s and computer’s brightness. The problem is less if your screen is too bright on its own—you’ll immediately feel uncomfortable staring at it, if so—but how much your eyes have to adjust looking back and forth between the two. “We generally recommend the difference between the brightest and darkest area of the room shouldn't be more than a three to one ratio,” Rosenfield says. Raise those blinds or turn on some lamps.

Consider, too, how close your screens get to your face. Our eyes have to focus harder on things closer to them, and of course on smaller text. That’s why looking at a phone for hours probably feels more tiring than looking at a desktop for the same amount of time—with computers, the text is probably bigger and the screen farther away (the ideal distance is about 16 inches).