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Link between screen time, myopia and sleep in Aussie study

Dr Ranjay Chakraborty myopia research Flinders Caring Futures Institute

An optometrist’s research at Flinders University has established a link between myopia and poor sleep quality due to increased screen time.

Dr Ranjay Chakraborty, from the Flinders Caring Futures Institute, led the study that found people with myopia have more delayed circadian rhythms and lower production of melatonin, a hormone secreted in the brain and responsible for regulating sleep at night, compared to people with normal vision.

The findings, published in the journal Sleep, showed participants with myopia took longer to fall asleep, sleep for shorter periods of time at night and were more likely to go to bed later or be ‘night owls’.

These sleeping habits were related to people with myopia spending more time on computers and other digital devices or studying before going to bed.

Chakraborty said the study added to the growing evidence of the potential association between disruption of the circadian rhythm and the development of myopia.

“Disruptions in circadian rhythms and sleep due to the advent of artificial light and the use of light-emitting electronic devices for reading and entertainment has become a recognised health concern in several fields, but its impact on eye health has not been studied extensively,” he said.

“These findings provide important evidence that optimal sleep and circadian rhythms are not only essential for general health, but also for good vision.”

In the study, conducted in collaboration with the Flinders University Adelaide Institute for Sleep Health, the circadian timing and production of melatonin was measured in both people with myopia and people with normal sight. All participants were university students, aged in their twenties.

Their melatonin levels were measured through saliva and urine samples, and those with myopia had significantly delayed circadian rhythms and lower outputs of melatonin compared to normal sighted participants.

Chakraborty said children’s sleeping habits and exposure to screen time must be re-evaluated to reduce the chances of myopia progressing in young people.

“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,” he said.

“It is important to limit the exposure to digital devices in children, particularly at night, for ensuring good sleep and healthy vision.”

Chakraborty hoped to expand his research.

“Because myopia typically develops during childhood, as a next step, we would like to examine circadian rhythm timing, total production of melatonin sleep and light exposure at night in young children – the actual target population for myopia prevention,” he said.

“Such a study will provide novel insights into the biological and environmental factors underlying myopia, which will aid in early diagnosis and treatment of myopia in children.”

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