Why screen time can disrupt sleep

For most, the time spent staring at screens – on computers, phones, iPads – constitutes many hours and can often disrupt sleep. Now, researchers have pinpointed how certain cells in the eye process ambient light and reset our internal clocks, the daily cycles of physiological processes known as the circadian rhythm. When these cells are exposed to artificial light late into the night, our internal clocks can get confused, resulting in a host of health issues.