The Vital Daylight

Russell Foster Portrait

Research and Innovation

Russell Foster

24 Feb 2021


Prof. Russell Foster, 2020 Laureate of The Daylight Award for Research was filmed in his study at Oxford University. In the documentary “The Vital Daylight” he explains his research on the eye’s ability to keep track of our circadian rhythm, using receptors unknown to us 20 years ago – a discovery with a wide-reaching impact.

After years of research, Prof. Russell Foster and his team of scientists discovered that the eye contains a third light sensor, beside rods and cones which are the photo receptors in human retina. It was discovered that there’s another light sensor within the eye that is used to lock the body clock and the sleep–wake cycle on to the external world; without which people would drift out of cue.

The rods and cones of the retina provide us with our sense of space or vision, but a small number of photosensitive retinal ganglion cells detect the overall amount of light in the environment and then align the body clock – providing us with our sense of time.

This discovery meant that people without the ability to see, are still able to regulate their internal clock.

The Vital Daylight featuring Russell Foster

Photosensitive Retinal Ganglion Cells (pRGCs)

In his interview held at the University of Oxford prof. Foster says: “What I’m excited about and trying to understand is how the core mechanisms of sleep and 24-hour circadian rhythms are generated and regulated within the central nervous system, and then use this fundamental knowledge for translational studies – to inform therapeutic approaches that will improve the quality of life for individuals and their family across a broad spectrum of health conditions where sleep is severely disrupted, from eye disease to mental illness.”

The jury of The Daylight Award 2020 stated: “Some researchers are laboratory scientists; others are clinical investigators. Professor Foster is both. His clinical studies in humans address important questions regarding light. How does morning light influence sleep? Why is light at night bad for health? And ultimately the answers to such questions have impacted the medical world in a variety of domains including sleep medicine, psychiatry, neurology, geriatrics, ophthalmology, immunology and even cancer medicine.”

Find out more about Russell Foster and his work at