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JINS supported a study led by Dr. Seiji Nishino and Dr. Shintaro Chiba, authorities on sleep research World's First*1! Wearing blue light blocking glasses before bedtime may help children sleep and wake up earlier and improve their daytime mood and behavior

JINS HOLDINGS Inc. (Tokyo Head Office: Chiyoda-ku, Tokyo, Founder & CEO: Hitoshi Tanaka, hereinafter “JINS”) has initiated support for a clinical study as part of its new initiative that aims to solve the social issue of declining sleep quality, drawing on the Company’s expertise in light gained through collaborations with industries and academia. With the support of JINS, a study (“Prospective, randomized, cross-over exploratory study on the effects on salivary melatonin concentrations in school children wearing blue light-blocking eyeglasses before bedtime”) was conducted by Dr. Seiji Nishino (Professor, Psychiatry and Behavioral Sciences, Stanford University School of Medicine; Director, Sleep and Circadian Neurobiology Laboratory, Stanford University; MD), Dr. Shintaro Chiba (MD; Director, Ota Memorial Sleep Center, Ota General Hospital), and Dr. Naoya Maeda (Postdoctoral Scholar, Psychiatry and Behavioral Sciences, Stanford University School of Medicine). For the first time in the world,1 the study suggested the effects of wearing blue light blocking glasses (with a 40% blue light reduction*2) before bedtime on children’s sleep. In 2023, the results were presented to the World Sleep Society, the Sleep Research Society and American Academy of Sleep Medicine, and the Japanese Society of Sleep Research.
*1 The world’s first clinical research on the impact on school children wearing blue light blocking eyeglasses before bedtime according to Dr. Nishino, Dr. Chiba, and Dr. Maeda.
*2 Refractive index of 1.60 and central thickness of 2.0 mm based on EN standard EN ISO 12312-1:2022.

Research on children was long awaited as more became known about relationship between sleep and blue light

JINS’ inhouse R&D office has been researching mainly blue light and violet light for many years in collaboration with industries and academia. Our study of blue light began before the word came into widespread use, when the academic research was still in its infancy. JINS is a pioneer in blue light research whose accomplishments include developing eyewear that protects eyes from blue light ahead of other companies.
Blue light and sleep have been subjects of numerous studies, which have found that exposure to blue light before bedtime adversely affects sleep and the circadian rhythm. However, these studies were carried out only on adults. Studies on children had never been conducted and were awaited globally. As a pioneer, JINS decided to support the above study, hoping to help further elucidate the relationship between blue light and sleep.

Research overview and results

This study compared the effects of wearing blue light blocking glasses and regular glasses on the sleep of 39 male elementary school children between ages 10 and 12 who were habitually exposed to blue light before bedtime. The research employed a methodology called crossover design in which participants were divided into two groups and variables were alternated between them. Group A wore blue light blocking glasses (prescription glasses with a 40% blue light reduction lens) provided by JINS for three hours before bedtime for two weeks. After a week of not wearing any glasses, the group wore regular glasses (prescription glasses with no blue light blocking) for three hours before bedtime for two weeks. Group B did the same in reverse order, wearing regular glasses first and then blue light blocking glasses. The researchers measured melatonin levels in saliva and objectively measured sleep onset and wake up times using a wearable acceleration sensor (actigraph). Questionnaires were also administered to survey changes in subjective behavior when children woke up and during daytime.
The findings showed no impact on salivary melatonin levels. On the other hand, wearing blue light blocking glasses for three hours before bedtime made children fall asleep and wake up earlier compared to wearing regular glasses, and the effects were noticeable in the second week. As a result of wearing blue light blocking glasses, wake-up times were earlier in the second week compared to the first week. In addition, daytime irritability and acting out toward siblings and friends scored lower during the second week compared to when regular glasses were worn.

In summary, the study suggested that wearing blue light blocking glasses before bedtime made children sleep and wake up earlier and improved their daytime mood and behavior.

Regarding the findings, Dr. Nishino commented as follows. “Japanese children get the shortest amount of sleep in the world, and their bedtime is getting later. Unlike adults, children rarely verbalize symptoms of poor sleep, such as ‘I couldn’t sleep well last night’ or ‘I feel sleepy during the day.’ Poor sleep often manifests in daytime behavior, such as mood swings, irritability, and difficulty concentrating. In this study, suppressing blue light exposure before bedtime by wearing glasses improved sleep patterns and daytime behavior in children, and these improvement mechanisms did not impact melatonin secretion. This finding is extremely interesting in terms of both social and academic implications. I am very excited about JINS’ future initiatives in the field of sleep sociology.” Dr. Chiba’s comment was as follows. “‘Sleep health’ is drawing attention around the world in recent years. Sleep health involves monitoring and improving routine habits and behaviors related to sleeping and waking up, with the aim of enhancing people’s mental and physical well-being and bringing happiness to all of society. The sleep duration of Japanese children is considered the shortest in the world. Japan’s busy society that prioritizes increasing economic growth and competitiveness has significant impact on the daily lives of children. In particular, this study showed that blue light has considerable effects on children’s sleep. Controlling blue light at the societal level will play an important role in children’s future and promoting child sleep health. I look forward to JINS’ future initiatives.” As a pioneer in blue light research, JINS aspires to continue to support advanced studies on sleep and spread scientifically grounded expertise to the broader society.