AUSTIN, Texas, June 15, 2021 /PRNewswire/ -- A new study has found that many blue light blocking glasses on the market do not filter enough sleep-disrupting light.
The research conducted by sleep scientists at the University of Arizona found that effectiveness varied greatly among products on the market, with some offering almost no protection against the colors of light that can disrupt sleep.
Dr Michael Grandner, Director of the University's Sleep and Health Research Program, along with Brooke Mason, a graduate student, put a total of 50 lenses from a variety of brands to the test to determine their effectiveness at filtering out short wavelength light, the part of the spectrum shown to suppress the body's natural release of sleep hormone melatonin.
They found that 23 of the tested brands blocked less than 50% of sleep-disrupting light.
"While blue light blocking can be an effective sleep aid, it's important to know that not all blue light blocking glasses are created equal," Dr Grandner said.
"Lenses that appeared mostly clear, for example, filtered very little of the sleep-disrupting light. Other lenses blocked a lot of the correct wavelengths of light but were so dark that they may be more difficult to wear. Some, though, struck a balance between performance and wearability at night."
Dr Grandner said that Swannies Blue Light Blocking Glasses, by Austin-based company Swanwick, were among the top performers in effectiveness at blocking sleep-disrupting wavelengths as well as in wearability.
"Among the 50 brands we put to the test, Swannies scored consistently well in all aspects that we tested.
"They have managed to combine effectiveness at filtering sleep-disrupting light while also allowing in non-sleep disrupting light, striking the right balance between sleep benefits and wearability and thus allowing for comfortable reading, screen viewing and night time activities without appearing too dark.
Tristan Swanwick, CEO and co-founder of Swanwick, advised customers to check if a brand publishes independent data on lens transmission and efficacy before purchasing.
Last year a study published in the Journal of Applied Psychology showed that people who wore Swannies in the evening before bed recorded longer and better quality sleep, as well as significant improvements in task performance the following day.
Dr Grandner and his team published their initial results at SLEEP 2021, the annual meeting of the Associated Professional Sleep Societies, LLC (APSS), which is a joint venture of the American Academy of Sleep Medicine (AASM) and the Sleep Research Society (SRS).
The University of Arizona did not receive any external funding for their research and Swanwick did not contribute financially to the independent study.
Dr Michael Grandner and Tristan Swanwick are available for interview. Photos and video are available upon request.