New research from Flinders University in Australia indicates people
with myopia are more likely to experience poorer sleep quality than
people with normal vision.
The study indicates that people with short-sightedness 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.
People affected by myopia or short-sightedness are familiar with the
frustration of only being able to clearly see objects up close, but not
a far distance.
Optometrist Dr. Ranjay Chakraborty , from the Flinders University
Caring Futures Institute, says the study adds 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 recognized health concern in
several fields, but its impact on eye health has not been studied
extensively," he says.
"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 Sleep Institute, 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
Melatonin is a hormone secreted by brain's pineal gland to maintain
the body's sleep-wake cycle and circadian rhythms. We produce melatonin
soon after the onset of darkness, peaking our secretion between 2 am to 4 am.
Dr. Chakraborty says the levels of melatonin were measured in
participants through saliva and urine samples, and that the young adults
with myopia had significantly delayed circadian rhythms and lower
outputs of melatonin compared to normal sighted participants.
Myopia is the most common vision disorder among children and
young adults and in severe cases predisposes them to several blinding
diseases in adulthood such as retinal tear and detachment, glaucoma, and
People with myopia can see objects near to them clearly, but objects
far away - like road signs - are blurry. The condition is caused by
excessive elongation of the eye in childhood. As a result the rays of
light entering the eye focus in front of the retina instead of directly
on the retina, causing blurriness.
Myopia generally occurs in children around the stage of puberty but
can also appear at any age in early childhood. Global cases of myopia
are on the rise, with some research indicating a link between excessive
screen use and on the onset of the condition.
Dr. Chakraborty says children's sleeping habits and exposure to
screen time must be re-evaluated to reduce the chances of myopia
progressing in young people.
Adequate sleep is critical for learning, memory, sustained
attention, academic performance at school, and general wellbeing of
children during the early development," he 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.
"It is important to limit the exposure to digital devices in
children, particularly at night, for ensuring good sleep and healthy
In terms of next steps from this research, there are a few options, says Dr. Chakraborty.
"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 says.
"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."
Source: News Release
May 23, 2021