Mark Halper has an interesting article in LED’s Magazine interviewing Russell Foster, the scientist who predicted the non-visual receptors in the eye that are involved in the circadian response to light (pRGCs / ipRGCs). He says circadian lighting science isn’t ready yet, and there are too many unknowns.

“We’re not ready yet,” said Foster, professor of circadian neuroscience at the University of Oxford. “We’re shuffling closely toward it, but there are major questions that remain unresolved. Yes, the toolkit is better than anything we’ve had before, but it is not the complete answer yet. We haven’t got the data to plugin.”

This is hardly what you’d expect from someone who, in the 1990s, posited the notion that certain cells in the eye’s retina receive light that has nothing to do with processing vision but has everything to do with maintaining the circadian rhythm.

Foster’s pioneering, decadelong hunch proved correct in 2002 when Brown University professor David Berson uncovered nonvisual photoreceptors, known as photosensitive retinal ganglion cells (pRGCs). Foster himself also found them soon thereafter.

“There are many critical factors — intensity, duration wavelength, time of day, task, a person’s light history, their age,” Foster pointed out. “All are really important. There’s this level of complexity, and we don’t know the answers to many of the important questions” that need answering in order to develop truly effective circadian lighting.

Read the full article here.