Eyeglasses with a filter designed to block blue light emitted from computer screens have almost no effect, according to an analysis of more than a dozen studies.
Researchers working with the Cochrane Database of Systematic Reviews poured over 17 studies published in medical journals and found almost no evidence that the glasses reduced eyestrain or helped people sleep better.
Of the 17 studies they reviewed, just three showed evidence that the blue-light filter reduced eye strain. However, those studies were short-term and only found a slight reduction in eyestrain.
"We found there may be no short-term advantages with using blue-light filtering spectacle lenses to reduce visual fatigue associated with computer use, compared to non-blue-light filtering lenses. It is also currently unclear whether these lenses affect vision quality or sleep-related outcomes, and no conclusions could be drawn about any potential effects on retinal health in the longer term. People should be aware of these findings when deciding whether to purchase these spectacles," senior study author Laura Downie said in a statement.
Study author Dr. Sumeer Singh noted that blue-light filtering lenses filter between 10% and 25% of blue light from computer screens or cell phones. Since most of the blue light comes from the sun, Singh said that glasses would need to be tinted to block out most of the blue light.
"Filtering out higher levels of blue light would require the lenses to have an obvious amber tint, which would have a substantial effect on color perception," he said in a statement.