Screen Time, Sleep Quality, and Myopia

Article: Sleep and screen time link to myopia
Source: Flinders University (Australia), via ScienceDaily
Published: May 27, 2021

Research led by an optometrist in Australia investigated the link between sleep quality and myopia. The findings indicate that people with near-sightedness have lower production of melatonin and more delayed circadian rhythms, compared to those with normal vision. The study involved a small cohort—18 myopes and 14 emmetropes—of university students, with endogenous melatonin levels measured through saliva and urine samples. The differences in sleep patterns in myopes compared to emmetropes include being more likely to go to bed later (i.e., be "night owls"), taking longer to fall asleep, and sleeping for shorter periods of time. Other research in the field suggest a link between excessive screen use and the onset of the condition in young children, with cases of myopia on the rise globally. As the researcher says, "A lot of digital devices emit blue light, which can suppress the production of melatonin and cause delay in circadian rhythms at night, resulting in delayed and poor sleep...Adequate sleep is critical for learning, memory, sustained attention, academic performance at school, and general wellbeing of children during the early development...It is important to limit the exposure to digital devices in children, particularly at night, for ensuring good sleep and healthy vision." He next plans to study light exposure at night, melatonin production, and circadian rhythms during childhood, when risk of developing myopia is highest.

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Chakraborty R, Micic G, Thorley L, et al. "Myopia, or near-sightedness, is associated with delayed melatonin circadian timing and lower melatonin output in young adult humans." Sleep.  44(3):zsaa208. 12 March 2021. https://doi.org/10.1093/sleep/zsaa208