EYES aren’t just for seeing, they also help set our body clock. And new
evidence for how this happens suggests that our eyes have a previously unknown
type of light-sensitive cell.
Light regulates our natural cycle of sleep and wakefulness, partly by
switching off the brain’s production of the sleep-inducing hormone melatonin
during the day. Debra Skene and her colleagues from the University of Surrey,
Guildford, wanted to find out whether some wavelengths of light were better than
others at suppressing melatonin. They shone light into 22 people’s eyes in the
middle of the night, when melatonin levels are naturally…
