Scientists at the Salk Institute have observed how certain cells in the eye process ambient light and reset the body’s circadian rhythm, meaning that screen time can disturb your sleep and lead to health issues.
The research on screen time and the affect on sleep was published in Cell Reports and may help lead to new treatments for migraines, insomnia, jet lag and circadian rhythm disorders. These disorders have been linked to other health issues such as cognitive dysfunction, cancer, obesity, insulin resistance, and metabolic syndrome.
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The impact of screen time on your sleep
The sensory membrane called the retina which is located at the backs of our eyes have a layer containing a tiny subpopulation of light-sensitive cells. The light-sensitive cells operate like the pixels in a digital camera.
When they are exposed to ongoing light, such as that caused by screen time on your smartphone or laptop, a protein called melanopsin continually regenerates within them.
The regeneration of melanopsin signals levels of ambient light to the brain to regulate consciousness, sleep, and alertness. Melanopsin plays a significant role in synchronising the body’s circadian rhythm after ten minutes of illumination.
Professor Satchin Panda, senior author of the study, said: “We are continuously exposed to artificial light, whether from screen time, spending the day indoors or staying awake late at night. This lifestyle causes disruptions to our circadian rhythms and has deleterious consequences on health.”
Ludovic Mure, staff scientist and first author of the paper, added: “Compared to other light-sensing cells in the eye, melanopsin cells respond as long as the light lasts, or even a few seconds longer. That’s critical, because our circadian clocks are designed to respond only to prolonged illumination.”
Previously Panda’s research team discovered that chemicals called opsinamides can lock melanopsin’s activity in mice without affecting vision, a potential avenue for therapies to address light hypersensitivity in migraine sufferers. The researchers aim to find ways to influence melanopsin to help with insomnia in future research.