Anti-blue light glasses are becoming more and more popular these days. Ads will say that the glasses can block the blue light emitted by the computer screen, preventing eye fatigue or a decrease in sleep quality. In recent years, anti-blue light glasses have even become a fashion trend. However, a recent review paper suggests that anti-blue light lenses may not be as effective as people think.
This paper, published in the Cochran Database of Systematic Reviews, summarizes the results of past trials on the effects of blue-light blocking lenses on eye fatigue, sleep quality and eye health. The authors of the paper found that wearing anti-blue light glasses did not relieve eye fatigue caused by computer screens. As for whether wearing special lenses before bed can improve sleep quality, the current evidence is not enough to draw valid conclusions.
"This is a wonderful review," said Mark Rosenfield, a professor at the State University of New York College of Optometry (who was not involved in the study). "This conclusion is not surprising at all... There have been a lot of studies that have "The results were exactly the same - there is no evidence that anti-blue light lenses have any effect on relieving eye fatigue." He also added that the new review once again emphasized the fact that although anti-blue light lenses are sold as relieving eye fatigue, But there is actually no evidence that they do this.
Research shows that some countries, including India, the UK and Australia, have high prescription rates for blue light blocking glasses. In 2019, researchers from the University of Melbourne surveyed Australian optometrists and found that about 75% prescribed blue light blocking glasses in clinical practice. Laura Downie, associate professor of optometry and visual sciences at the University of Melbourne and co-author of the 2019 study, decided to delve into the existing evidence that glasses reduce eye fatigue, poor sleep quality and visual impairment caused by electronic devices. How about the quality.
In this newly published review, Downey and colleagues counted 17 trials of randomized control variables across six countries. These studies ranged in size from 5 to 156 participants and in duration from less than a day to 5 weeks. Analysis of the experimental results showed that wearing anti-blue light glasses did not significantly relieve eye fatigue in the short term compared with standard clear lenses. Additionally, only one study has tested the effect of blue light-blocking glasses on vision—and the result was virtually no effect. Researchers also don't know the effects of blue-light blocking lenses on other aspects of eye health, such as retinal damage, because no trials have examined this.
Although it is widely believed that blue light causes or worsens eye fatigue, Rosenfeld believes that the connection between the two is actually weak. The largest source of blue light is the sun, and the blue light emitted by the screens of electronic products is less than 1% of what the human eye receives from solar radiation. Additionally, there is no known physiological mechanism linking blue light to eye fatigue, he added.
Downey said that after staring at a mobile phone or computer screen for a long time, we may feel that our eyes are tired, which may be caused by a variety of factors, such as poor eye habits or other underlying pathological factors. Both she and Rosenfeld believe the way we interact with electronic devices is more harmful to our eyes than blue light. Downey said that if you want to relieve eye discomfort, it is more important to change the time and frequency of screen use, and adjust the distance between the human eye and the screen. She added that people who frequently experience eye strain should see a doctor to evaluate themselves for underlying health problems, such as farsightedness or dry eye syndrome.
Poor sleep has also been linked to the blue light emitted by screens. Past research has shown that using electronic devices late at night can disrupt sleep patterns, Rosenfeld said. Blue light is known to interfere with the production of melatonin, which sends sleep signals to the brain. This has led many researchers to link disrupted sleep cycles to blue light.
But Downey and his team's analysis shows that wearing blue light-blocking glasses before bed may not be helpful. Although six experiments have examined whether wearing blue light-blocking glasses before bed affects sleep quality, the results have been inconsistent. Three studies reported significant improvements in sleep quality after using blue light-blocking glasses, while three other studies reported no significant differences between the experimental and control groups. Participants in these trials were also mostly people with sleep disorders. Downey and his colleagues couldn't draw any conclusions about whether blue-light-blocking glasses would be useful for the average adult.
Rosenfeld said another way to improve sleep might be to activate the "night mode" or "dark mode" that comes with many smartphones. These modes cause the screen to emit warmer colors, reduce glare and emit less blue light. However, it's still unclear whether this setup is better for sleeping than specialized glasses.
More research is needed on blue light and blue-light blocking lenses to understand the impact on eye protection, Rosenfeld said. For example, more information is needed about whether certain wavelengths of blue light are more harmful than others. Researchers may also consider testing blue-light blocking glasses to block more blue light.
As for using blue light-blocking glasses for eye health, right now, Rosenfeld said, "There's very little reason for people to buy them."