Dieter Lang of Osram warned of how blue light can damage the retina if it is too intense, and outlined ways for luminaire manufacturers to assess and mitigate these risks.
But the effect of blue light goes further, because of the way it guides our bodily rhythms.
PhotonStar’s Fenella Frost said light is the ultimate ‘zeitgeber’ – the external cue that our bodies use to determine what time of day it is, and whether we need to rest or stay alert.
Frost shared some dramatic examples of the effects of blue light (specifically at 460nm) at the wrong time of day. In studies on mice, the mice gained weight, were more likely to get cancer, and in one study lived for half as under natural daylight.
In a study in a care home for the elderly, amber lighting at night helped people sleep and reduced instances of dementia. In a school, students’ reading speed increased by 35% after the introduction of dynamic lighting. Errors and hyperactivity were also drastically reduced.
But even light sources with a warm colour temperature can include high levels of blue, so using warm light later in the day doesn’t necessarily solve the problem (PhotonStar’s Chromawhite technology, which tunes the colour of light from LEDs, is designed to offer a way around this).
Not all lighting designers are also experts in health and wellbeing, but they increasingly need to take these issues into account in their work.