The marketing around blue-light filtering or blocking lenses have been gaining popularity in recent years – with claims that they can boost visual performance while using devices like a smartphone or computer, protect your eyes from fatigue, and even improve sleep quality (because blue light is meant to suppress melatonin). A recent Cochrane review from researchers at the University of Melbourne and in the UK examined clinical trials to filter these claims.
Researchers scanned multiple databases, including Cochrane and Medline, focusing on randomised controlled trials of adults where the blue-light filtering glasses were compared to regular lenses. The outcomes they looked at included visual fatigue, visual performance, macular protection and sleep quality. The final review included 17 RCTs, though the typical sample size of the included studies was very small. The largest trial only had 156 participants.
The evidence suggested no noticeable difference in visual fatigue between users of blue-light filtering lenses and those of regular lenses. There was no difference in critical flicker-fusion frequency (a test where people record when they can no longer detect whether a light is flashing or steady, to measure of visual fatigue) or visual performance. They couldn’t say with any certainty that the blue-tinted glasses helped with sleep or not, because studies were too varied in the outcomes they reported. Some users of blue-light glasses reported side effects (though reports were rare). These included increased depressive symptoms, headaches, and general discomfort related to the use of the lenses.
While blue-light filtering lenses might seem promising based on marketing claims, this systematic review suggests they may not alleviate eye strain from computer or mobile use and don’t help with visual performance. The potential benefits on sleep quality remain unclear, and there is zero evidence they help to protect macular health. For consumers considering such glasses, better studies are needed to show that the benefits match the marketing claims.