Blue light is just a frequency, and it’s always been an essential part of the human visual experience. In fact, it has health benefits. According to Raj K. Maturi, a professor at the Indiana University School of Medicine and a clinical spokesperson for the American Academy of Ophthalmology, exposure to blue light via the sun helps prevent nearsightedness, especially in kids. Blue frequencies also help regulate humans’ daily wake-sleep cycles by preventing our bodies from producing melatonin during the daytime, which is a hormone that makes people sleepy at night.
Because blue light blocks melatonin production, Maturi did see one potentially smart use for the new crop of fashion glasses proliferating on Instagram: to block blue light in the evening hours, when exposure to it might make it harder for your body to fall asleep. “If you’re looking at your screens late at night, there’s a lot of blue in there, and then your body doesn’t adequately produce melatonin,” he says. Still, Maturi could find no justification for wearing the glasses during the daytime, and the problem of melatonin production can also be addressed via devices’ built-in night modes.
Nevertheless, some consumers swear by their new glasses, even if they don’t do anything to directly affect how their eyes and devices interact. The writer Gina Tomaine wore a pair for a week to document her experience for Good Housekeeping, and although she recommends the glasses, she admits that they functioned mainly as an awareness tool. “Since the glasses made me more aware of blue light, I tried remedying the issue further with small fixes,” she wrote. Those small fixes included avoiding excess screen time and changing the contrast on her devices to be more sleep friendly before bed.
Those changes were what probably made a difference in how Tomaine’s eyes felt, not the glasses—the extra steps she took are what all of the medical professionals I spoke with recommended for consumers whose eyes feel tired, no new products required. Maturi also mentioned a piece of advice that eye doctors commonly give to patients: the 20/20/20 method. To do it, all you have to do is look up from what you’re doing every 20 minutes and switch your focus to something 20 feet away, for 20 seconds. That lets the muscles in and around your eyes relax, and it costs nothing.
Read: How to keep computer screens from destroying your eyes
If you follow lifestyle bloggers on Instagram, you know that a largely unspoken part of their job is to look like they’ve defeated the vague anxieties of modern life, and many make a living by selling you products and experiences that promise to draw you closer to that ideal. Some of those products, like swan-shaped pool floats or artisanal home textiles, are harmless and fun. Others, like flat-tummy laxative teas and junk-science juice trends, can exploit the difficult and sometimes dark relationship many young people have with their body and the realities of modern American culture. Blue-light blockers provide a quick, fashionable fix to a looming anxiety, and they hit a gap in pop-cultural medical knowledge where people might be inclined to take brands or influencers at their word.