NEW YORK – The pitch for blue light-filtering glasses is compelling: an easy way to counteract that bleary-eyed feeling that sets in after hours of scrolling on your mobile phone or staring at a laptop.
The evidence for them, though, has largely been lacking. And a new review of 17 studies adds to a growing consensus that they probably do not prevent or relieve eye strain.
The phrase blue light refers to a range of wavelengths of light around people – the sun emits it, and so do screens.
Some experts have wondered whether blue light could be behind “computer vision syndrome” – a condition that encompasses the eye irritation and other issues, including headaches and blurred vision, that many people experience after extended screen time.
But blaming blue light for this is contentious, said Associate Professor Laura Downie of optometry and vision sciences at the University of Melbourne and an author on the new review.
She and the team found that there appeared to be no benefit to using blue light-filtering glasses, compared with just standard lenses, to reduce eye strain. The trials included in the review were relatively small – the largest had 156 participants.
Researchers have long been sceptical that blue-light glasses can curb eye strain, said Professor Mark Rosenfield at the State University of New York College of Optometry.
Previous studies have also typically been small, but several have found that the lenses did not prevent people’s eyes from tiring or getting irritated, and did not appear to improve vision.
The new review found mixed results for blue light-filtering glasses and sleep. Some studies showed improved sleep scores among wearers, while others showed the opposite.
There is evidence that blue light may also take a toll on sleep by inhibiting the brain’s ability to secrete melatonin, the hormone that gets people ready to rest, said Dr Raj Maturi, a spokesman for the American Academy of Ophthalmology.
The amount of blue light that a phone or computer emits is actually quite low, Prof Downie said, which might be why blocking it does not do much to ameliorate eye strain.
But if you spend four or more hours a day on a computer, you are nonetheless at risk for screen-induced eye irritation, she added.
The way people use their eyes when they stare at a screen for long periods of time, especially close up to their faces, can cause discomfort.
Prof Downie and other experts recommend a few tips that may help.
- Lubricate your eyes: Part of the reason your eyes might ache is that you blink far less when glued to a screen, said Dr Craig See, an ophthalmologist at Cleveland Clinic’s Cole Eye Institute. 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.
- Give yourself a break: Eye health experts often recommend the “20-20-20” rule: Every 20 minutes, take a 20-second break to look at something 20 feet, or 6m, away. This exercise helps the eye muscles relax, Dr Maturi said. However, some researchers have suggested that 20-second breaks may not be long enough.
- Reduce glare: It is important to consider the light in your entire room, not just the kind coming from your computer. Reflections and glares on your screen can strain your eyes, Prof Downie said. Make sure your computer is positioned to minimise reflections from light sources and reflective surfaces like windows and glass doors.
- Placement is everything: Keep the centre of your screen just below eye level, and if you are experiencing eye strain, try moving your computer farther away. The ideal range is generally 50 to 75cm away from your head, Prof Downie said. The same advice goes for your phone. Your eyes have to work harder when you hold your phone close to your face, Prof Rosenfield said. Try to hold it at least 40cm away, he suggested.
- Get help: If you are consistently feeling eye strain, and none of these solutions are working after three or four weeks, seek an eye specialist, Dr Maturi advised. NYTIMES