The proposal of blue light filter glasses is attractive: an easy way to neutralize that feeling of tired eyes that arises after hours of browsing on your cell phone or looking at a laptop.
The evidence in favor of them, however, is not much. And a new review of 17 studies adds to a growing consensus that they probably don’t prevent or alleviate eye strain.
The term “blue light” refers to a range of wavelengths of light that are all around us — it’s emitted by the sun, and by screens too. In recent decades, some experts have wondered whether blue light is to blame for “computer vision syndrome” — a condition involving eye irritation and other problems, including headaches and blurred vision, that many people experience after a long time of use. screen. But blaming blue light for this is controversial, said Laura Downie, associate professor of optometry and vision sciences at the University of Melbourne (Australia) and author of the new review.
She and her team found that there seemed to be no benefit to wearing blue-light-filtering glasses, compared to standard lenses, in reducing eye strain. The trials included in the review were relatively small—the largest had 156 participants.
Researchers have long been skeptical that blue light glasses can reduce eye strain, said Mark Rosenfield, a professor at the State University of New York College of Optometry. Previous studies have also generally been small, but several found that the lenses didn’t keep people’s eyes from getting tired or irritated, and didn’t appear to improve vision.
The new review found mixed results for blue light-filtering glasses and sleep: some studies showed better sleep scores among wearers, while others gave the opposite result. There is evidence that blue light can also impair sleep by inhibiting the brain’s ability to secrete melatonin, the hormone that prepares us to rest, said Dr. Raj Maturi, a spokesman for the American Academy of Ophthalmology and a retinal expert at the Institute. of Olhos do Centro-Oeste.
The amount of blue light a phone or computer emits is actually quite low, Dr. Downie said, which may be why blocking it doesn’t do much to improve eye strain. But if you spend four or more hours a day on a computer, you’re still at risk for screen-induced eye irritation, she added. The way we use our eyes when looking at a screen for long periods of time, especially close to our face, can cause discomfort.
Dr Downie and other experts have recommended some tips that may help.
Lubricate your eyes
Part of the reason your eyes may hurt is that you blink a lot less when you’re glued to a screen, said Dr. Craig See, an ophthalmologist at the Cole Eye Institute at the Cleveland Clinic. This means your eyes dry out more easily. If you regularly experience eye strain, consider using eye drops three to four times a day, Dr. Maturi recommended.
“I often tell people that if you know your eyes tend to get gritty, almost like something has gotten into them, after using the computer, you can even put artificial tears in before you sit down,” said Dr. Ehrlich, assistant professor. of ophthalmology and visual sciences at the University of Michigan.
Eye health experts often recommend the “20-20-20” rule: every 20 minutes, take a 20-second break and look at something 20 feet (6 meters) away. This exercise helps to relax the eye muscles, said Dr. Maturi. However, some researchers have suggested that 20-second intervals may not be long enough.
It’s important to consider the light in the entire room, not just that coming from the computer. Reflections and glare on the screen can strain your eyes, Dr. Downie said. Make sure your computer is positioned to minimize reflections from light sources and reflective surfaces, such as windows and glass doors.
Position is everything
Keep the center of the screen just below eye level and, if you have eye strain, try moving the computer away from you — the ideal distance is generally 50 to 70 centimeters from your head, said the doctor.
The same advice goes for your phone: Your eyes have to work harder when you hold the phone up to your face, Dr. Rosenfield said. Try to hold it at least 15 inches away, he suggested.
Ask for help
If you experience constant eye strain and none of these solutions work after three or four weeks, see an ophthalmologist, advised Dr. Maturi.
There are some tools that can be equally effective in helping you sleep, such as special glasses, Dr. Rosenfield said. For example, some smartphones automatically change the screen to warmer tones (“night light”) after a set time. The American Academy of Ophthalmology recommends that people use apps like f.lux to change the color of their screens at night, which can help emit less blue light.
Translated by Luiz Roberto M. Gonçalves