Scientists from the University of Melbourne have found that blue light-blocking glasses do not affect sleep quality or eye strain while working at a computer. Study published in Systematic Review Database Cochrane Library.
Manufacturers of lenses that block blue light promise their wearers to reduce eye strain associated with the use of digital devices, improve sleep quality, and protect the retina from damage.
In the new review, the scientists analyzed data from 17 high-quality trials from six countries. The number of participants in individual studies ranged from five to 156, and the time the lenses were tested ranged from one day to five weeks.
Scientists have not found any short-term benefit to wearing glasses that block blue light. They did not affect the participants’ visual fatigue or sleep quality.
The state of the retina, the light-sensitive tissue at the back of the eye, has not been evaluated in high-quality studies, so the effectiveness of glasses in this regard has also not been proven.
“The results of our review, based on the best available evidence, show that the efficacy of the lenses is inadequate and uncertain. Our findings do not support the prescription of blue-light filter lenses for the general population,” explained the authors.
The mechanisms by which lenses that filter blue light can help with eyestrain, poor sleep quality, and retinal protection are unclear. One reason to claim the benefits of these lenses is that computer and smartphone screens emit more blue light than traditional light sources.
The short follow-up period prevented the authors from assessing the long-term benefits of the lenses. But the authors of the new review cautioned that the amount of blue light our eyes receive from artificial sources is only one-thousandth of natural daylight. Additionally, glasses that filter blue light typically block about 10-25% of blue light. For best performance, the lenses should be amber, which significantly affects color perception.
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